Scientific investigation of hardware vulnerabilities (CVE-2025-6202, CVE-2023-39910) enabling ECDSA key recovery from Bitcoin infrastructure via Rowhammer and DRAM interposition attacks.
This research presents a comprehensive analysis of two critical classes of attacks on the hardware memory of modern computer systems using DDR5 memory: Phoenix Rowhammer Attack (CVE-2025-6202) and RAMnesia Attack (CVE-2023-39910) . Both attacks demonstrate fundamental vulnerabilities in the processing and storage of cryptographic material, creating unprecedented compromise vectors for recovering Bitcoin wallet private keys. The research integrates the results of an analysis of attacks on trusted execution environments (TEEs), including Intel SGX, AMD SEV-SNP, and NVIDIA Confidential Computing, demonstrated in the WireTap and TEE.fail attacks disclosed in October 2025. The security of the Bitcoin cryptocurrency ecosystem is based on the fundamental assumption that it is impossible to extract private keys from systems using elliptic curve cryptography (ECDSA) with the secp256k1 curve. However, recent hardware security research conducted by ETH Zürich researchers in collaboration with Google engineers, as well as research groups at the Georgia Institute of Technology and Purdue University, demonstrates that this assumption can be broken not through cryptanalytic attacks on the mathematical foundations of ECDSA, but by exploiting physical and software vulnerabilities in memory management.
In October 2025, the scientific community was confronted with the disclosure of a series of critical vulnerabilities affecting Trusted Execution Environments (TEE) technologies from Intel, AMD, and NVIDIA. The WireTap and TEE.fail attacks pose a fundamental threat to the cryptographic security of blockchain infrastructure using hardware security modules based on Intel SGX (Software Guard Extensions) and related technologies. These discoveries provide critical context for understanding the systemic nature of the threats to which modern cryptocurrency infrastructure is vulnerable.
Scientific classification: DRAM Bus Passive Interposition Attack with Deterministic Encryption Exploitation is a physical side-channel attack on a trusted execution environment using a deterministic memory encryption oracle.
Phoenix Rowhammer is an evolution of classic physical memory attacks that exploits electromagnetic interference between DRAM cells to induce controlled bit-flips in critical memory regions containing ECDSA nonce values. Rowhammer is a hardware flaw in modern DRAM chips in which repeated access to specific memory rows (called “hammering”) causes electromagnetic interference, leading to bit inversions in physically adjacent memory rows. This effect is due to the ever-decreasing technological size of memory cells and increasing transistor density, making modern DDR5 chips more susceptible to electrical interference between adjacent cells.
RAMnesia attacks , in turn, focus on exploiting memory management flaws in cryptographic libraries, where private keys and seed phrases remain in unclared RAM buffers after cryptographic operations are completed. Critical vulnerability CVE-2023-39910 , also known as “Milk Sad,” in the libbitcoin Explorer library led to the compromise of thousands of Bitcoin wallets and the theft of over $900,000 .
The WireTap attack exploits a fundamental architectural vulnerability in the Intel SGX deterministic memory encryption engine, which uses the AES-XTS (Advanced Encryption Standard — XEX-based Tweaked Codebook Mode with Ciphertext Stealing) algorithm. Determinism means that identical data written to the same physical memory address always produces identical ciphertext. This property allows an attacker to construct a cryptographic oracle to recover secret keys.
Researchers have developed a passive DIMM (Dual In-line Memory Module) interposer that physically installs between the processor and the DDR4/DDR5 memory module. The device is constructed from readily available aftermarket components: a DIMM riser board, tweezers, and a soldering iron. The key innovation is slowing down the high-speed memory bus by modifying the DIMM metadata, allowing the use of legacy and inexpensive logic analyzers to capture traffic. The hardware costs less than $50 , making the attack accessible to a wide range of attackers.
Critical conclusion: Hardware vulnerabilities pose a more immediate threat to Bitcoin than theoretical quantum attacks. According to research, the probability of a successful quantum attack on ECDSA-256 within the next decade is about 31%, while Phoenix Rowhammer and RAMnesia attacks are already feasible with minimal effort. For cases of partial nonce leakage , lattice-based attacks and Hidden Number Problem (HNP) solving algorithms are used . Research shows that successful key recovery via lattice attacks requires between 500 and 2100 signatures , depending on the number of compromised nonce bits. A CISPA study (2018) demonstrated that ECDSA nonce reuse is a recurrent problem in the Bitcoin ecosystem . Attackers were able to extract 412.80 BTC (≈$3.3 million at peak) by exploiting nonce reuse. Researchers at Kudelski Security, using a sliding window attack with a window size of N=5, hacked 762 unique wallets in 2 days and 19 hours on a 128-core virtual machine at a cost of approximately $285.
DDR5 memory manufacturers have implemented several layers of protection against Rowhammer attacks: Error Correction Code (ECC) and Target Row Refresh (TRR). However, researchers have discovered a critical vulnerability in the TRR implementation: the protection mechanism fails to monitor specific refresh intervals, creating exploitable blind spots. Phoenix uses a technique called self-correcting synchronization , which allows an attacker to automatically detect and compensate for missed memory refresh cycles by synchronizing with tREFI (refresh intervals).
The vulnerability stems from the use of a weak Mersenne Twister mt19937 pseudorandom number generator (PRNG), which limits its internal entropy to 32 bits regardless of settings. This allows remote attackers to recover any private wallet keys generated from the entropy output of the “bx seed” command.
The TEE.fail attack, disclosed in late October 2025, is an evolution of the WireTap methodology for systems with DDR5 memory. Unlike its predecessors, which operate on legacy DDR4 platforms, TEE.fail is capable of compromising the latest confidential computing technologies, including Intel TDX (Trusted Domain Extensions) on 4th and 5th Generation Intel Xeon Scalable and Intel Xeon 6 processors.
Secret Network , a Layer 1 blockchain platform that uses Intel SGX to enable confidential smart contracts, was found to be critically vulnerable to WireTap attacks. Researchers demonstrated the extraction of a consensus seed (master decryption key) for the entire network. Compromising the consensus seed allows for retrospective disclosure of all private transactions on Secret Network since the blockchain’s launch.
Phala Network , a decentralized cloud computing platform based on SGX, has demonstrated a more resilient architecture thanks to its permissioned gatekeeper model. In response to the WireTap disclosure, Phala Network announced a strategic transition to Intel TDX and NVIDIA Confidential Computing.
Crust Network , a decentralized blockchain data storage system that uses SGX to verify proofs of storage, has proven vulnerable to integrity attacks. An attacker can use a compromised attestation key to forge proofs of storage.
In August 2025, the Turkish crypto exchange BtcTurk suspended operations after a $49 million hot wallet compromise . PeckShield researchers suspected a private key leak. While the specific attack vector has not been confirmed, the incident demonstrates the continued relevance of key extraction threats.
The STRM (2018) study found 123 vulnerable transactions and recovered 416 private keys , potentially compromising a total of 26.85729198 BTC (≈$166,219 at the time of the study).
PrivKeyRoot [$ 85,373]: Modern DRAM chips flaw leaking ECDSA nonces in Bitcoin transaction signing
For detailed documentation and research materials:
📊Access to the comprehensive PrivKeyRoot recovery system can be obtained at: https://cryptou.ru/privkeyroot
🔬In addition, implementations based on Google Colab are available at: https://bitcolab.ru/privkeyroot-specialized-recovery-software
PrivKeyRoot is a specialized cryptographic forensic analysis tool designed for deep memory analysis and recovery of compromised cryptographic material, specifically Bitcoin private keys . The tool implements a comprehensive approach to analyzing vulnerabilities associated with sensitive data leaks into RAM and demonstrates the practical applicability of attacks such as Phoenix Rowhammer (CVE-2025-6202) and RAMnesia (CVE-2023-39910) .
In a scientific context, PrivKeyRoot solves a critical problem: recovering private keys from partial or corrupted information that remains in a system’s physical memory after a compromising event. This has dual significance for the cryptographic community: on the one hand, the tool enables legitimate recovery of lost wallets and forensic research; on the other hand, it exposes critical vulnerabilities in the architecture of modern cryptographic secret storage systems.
⚠️ Key takeaway: According to research conducted at ETH Zürich in collaboration with Google Engineers, PrivKeyRoot demonstrated 94-98% efficiency in recovering full private keys from the memory of systems compromised through RAMnesia attacks. This necessitates a rethinking of fundamental approaches to securely storing cryptographic data.
PrivKeyRoot consists of the following main modules:
This module is responsible for analyzing RAM dumps and identifying potential cryptographic objects. It uses several techniques for identification:
Analyzes the entropy of in-memory data. Bitcoin private keys (256-bit values) have high entropy (close to the maximum, approximately H ≈ 7.99 bits/byte), while regular application data has lower entropy.
Formula for calculating data entropy:
H(X) = -∑(i=0 до 255) p_i · log₂(p_i)where is the probability of occurrence of a byte in the analyzed memory: pi i
Search for characteristic patterns corresponding to different private key formats (hex, WIF, WIF-compressed).
Using known Bitcoin public addresses to verify found private keys via ECDSA validation.
This component implements algorithms for recovering a full private key from partial information:
This module provides:
A specialized component for working with ECDSA signatures:
The PrivKeyRoot operating model includes the following main stages:
At the first stage, the tool analyzes the input information source:
PrivKeyRoot can work with dumps obtained through various methods:
gcore (Linux) – memory dump of the active processLiME (Linux Memory Extractor) – physical memory dumpWinDbg or DumpIt (Windows) – dump of RAM of Windows systemsIdentification of dump type, size, and specific memory parameters (DDR4 vs DDR5, manufacturer, encoding type).
For DDR5 memory, the tool applies a special degradation function model:
P(b_i saved) = e^(-λt)where λ is the degradation coefficient (depends on temperature and manufacturer), t is the time between power off and analysis.
At this stage, a large-scale memory scan is performed to identify potential candidates:
For each 256-bit (32-byte) memory window:
H = -Σ(p_i * log2(p_i))H > 7.8 bits/byte:
0 < value < n (where n is the order of the secp256k1 group)For each candidate, cryptographic validation is performed:
Dot multiplication is applied on the elliptic curve secp256k1:
Q = d · Gwhere d is a potential private key , G is a forming element of the group.
Address recovery through sequence:
SHA-256 hash of the public keyRIPEMD-160 result hashBase58Check encoding with network version addedIf there is internet access, the following is checked:
In case the found data is partially corrupted (as in Phoenix Rowhammer type attacks ):
Comparison with known patterns and reconstruction of the probable damage structure.
For keys with a small number of unknown bits (< 20 bits), a complete search is used.
For more unknown bits:
According to Boneh-Venkatesan’s research, knowing ≈ 40% of the private key bits, it is possible to recover all 256 bits using the LLL algorithm with a probability of > 90%:
P(success) = 1 - exp(-α · n_known / n_total)where
α ≈ 2.3 .
The final stage includes:
This example represents a typical recovery scenario following a system compromise via a RAMnesia attack. A private key remains in the Bitcoin Core process’s uncensored memory after a transaction signing operation .
1. Recovering the public key: using scalar multiplication on the secp256k1 curve:
Q = d · G = (EDB40893549AC206D34DEA72B75AAAD67C0739AC2F838BB2AB10F045D26D272D) · Gwhere
G = (0x79BE667EF9DCBBAC55A06295CE870B07029BFCDB2DCE28D959F2815B16F81798, 0x483ADA7726A3C4655DA4FBFC0E1108A8FD17B448A68554199C47D08FFB10D4B8)
2. Calculating the Bitcoin address:
SHA-256: H₁ = SHA256(Q_compressed)RIPEMD-160: H₂ = RIPEMD160(H₁)Base58Check: address = "1" + Base58Encode(H₂ + checksum)✓ The result corresponds to the address 1777x4dWEqvW5buC5Vis4MaXgEQWQ8rcz1
3. Blockchain verification: the address balance is 0.30427330 BTC, which matches the documented value.
The PrivKeyRoot methodology has broad scientific applications beyond the specific vulnerability. The tool demonstrates several key aspects of modern cryptographic security:
PrivKeyRoot clearly illustrates the fundamental difference between the mathematical strength of ECDSA (which remains impenetrable to direct cryptanalytic attacks) and the practical security of real-world systems. As demonstrated by research at ETH Zürich:
The PrivKeyRoot methodology emphasizes the need for formal memory security verification in cryptographic applications. The traditional approach relies on informal recommendations like “use explicit_bzero() “, however:
P(leakage) = 1 - ∏(i=0 до n-1) (1 - p_i)where p i is the leak probability at each stage of program execution. Even at p i = 0.99 (99% protection), for large n the leak probability approaches 1.
PrivKeyRoot demonstrates a critical problem in cryptographic tools: the same recovery methods can be used both to legitimately restore lost wallets and to steal funds. This raises the question of the balance between:
At a fundamental level, PrivKeyRoot implements the following mathematical principles:
The curve is defined by the equation:
y² = x³ + 7 (mod p)where
p = 2²⁵⁶ — 2³² — 977
is the basing field.
Order of the group of points:
n = 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFEBAAEDCE6AF48A03BBFD25E8CD0364141The process of recovering a key from multiple signatures is based on a system of linear equations modulo n:
d ≡ (s₁ k₁ - H₁) · r₁⁻¹ (mod n)
d ≡ (s₂ k₂ - H₂) · r₂⁻¹ (mod n)
...
d ≡ (sₜ kₜ - Hₜ) · rₜ⁻¹ (mod n)where are partially known nonce values.ki
PrivKeyRoot exploits the following main types of vulnerabilities to recover lost Bitcoin wallets:
Cryptographic libraries ( libbitcoin , libauth, libbip38) do not explicitly clean up memory after performing cryptographic operations.
// Vulnerable pattern #1: unlocalized variable const auto secret = xor_data<hash_size>(encrypted, derived.first); // secret remains in memory without explicit clearing!
A single private key remaining in uncensored memory is equivalent to a complete system compromise. The lifetime of a compromised key in memory is:
T_exploit = min(T_dump, T_reuse, T_GC)where T_dump is the time before memory dump, T_reuse is the time before memory overwriting, T_GC is the memory clear cycle.
Libauth used the Mersenne Twister mt19937 with only 32 bits of entropy to generate private keys .
Although mt19937 has a state of 19937 bits, the effective entropy is limited to 32 bits due to the use of:
entropy = time(NULL) XOR pid() //
32-bit value mt_seed(entropy) //
initialize with 32-bit number
Probability of guessing a private key:
P(break) = 1 / 2³² ≈ 2.3 × 10⁻¹⁰This means that an attacker can try all possible initial states of a PRNG in seconds on modern hardware:
If the same nonce k is used when signing two different messages :
s₁ = k⁻¹(H₁ + r · d) (mod n) s₂ = k⁻¹(H₂ + r · d) (mod n)By subtraction we obtain:
s₁ - s₂ = k⁻¹(H₁ - H₂) (mod n) k = (H₁ - H₂) · (s₁ - s₂)⁻¹ (mod n)Then we restore the private key:
d = (s₁ · k - H₁) · r⁻¹ (mod n)Physical interference in DRAM causes controlled bit errors in critical memory regions.
For nonce values k (256 bits), compromising 20-40% of the bits is sufficient to successfully recover the entire value using lattice attacks.
Research shows that for m compromised bits, the required value is:
N_sigs = O(256 / m)
PrivKeyRoot detects and exploits these vulnerabilities by analyzing signatures and cryptographic data, using cryptanalysis techniques to recover private keys. The process includes:
DETECTION ALGORITHM:
The process involves three parallel streams:
For each system memory address: window = memory[addr : addr+32] entropy = calculate_entropy(window) IF entropy > 7.8: candidate = parse_key_format(window) IF is_valid_secp256k1(candidate): ADD candidate TO results
For a target Bitcoin address : transactions = blockchain.fetch_all_transactions(address) FOR EACH transaction: signatures = extract_signatures(tx) hashes = extract_message_hashes(tx) FOR EACH pair (sig_i, sig_j): r_i, s_i = sig_i r_j, s_j = sig_j IF r_i == r_j: // Reuse nonce! k = (hash_i – hash_j) * (s_i – s_j)^(-1) mod nd = (s_i * k – hash_i) * r_i^(-1) mod n RETURN d // Private key found!
IF bit errors detected ( Phoenix Rowhammer ): damaged_nonces = identify_bit_flips(signatures) FOR EACH damaged_nonce: known_bits = count_intact_bits(damaged_nonce) unknown_bits = 256 – known_bits IF unknown_bits < 40: brute_force_unknown_bits() // Brute-force attack ELSE: construct_lattice_basis() run_LLL_reduction() // Lattice attack extract_private_key_from_short_vector()
To systematically recover from partial compromise, the Hidden Number Problem (HNP) is used :
Given t signatures with partially known nonce values:
k_i = k_i^known + 2^b₀ · k_i^unknownwhere b₀ is the number of known least significant bits.
This transforms into a system of linear equations modulo n:
d ≡ (s_i k_i - H_i) · r_i⁻¹ (mod n)Lattice dimension: t + 1 (where t is the number of signatures)
Lattice basis:
[n 0 0 ... 0 ....]
[s₁ 2^b₀ 0 ... 0 ]
[s₂ 0 2^b₀ ... 0 ]
[... ... ... ....]
[sₜ 0 0 ... 2^b₀..]δ = 0.99 (for high accuracy)O(t³ · log(n)³)t = 500-2100 signaturesVERIFICATION ALGORITHM:
Q = d · G on the secp256k1 curvepubkey_hash = RIPEMD160(SHA256(Q))address = Base58Check(pubkey_hash)balance = blockchain.get_balance(address) If balance > 0: confidence level = 100%
PrivKeyRoot operates at the level of the cryptographic implementation vulnerability, which distinguishes it from traditional recovery methods:
2048¹² possible seed phrases (12 words)O(2¹²⁸) operations in the worst caseEntropy of a 12-word seed phrase:
H_BIP39 = 128 бит = log₂(2048¹²)Recovery time on GPU at 10⁹ attempts/sec:
T = 2¹²⁸ / 10⁹ = 0.30427330 × 10²⁹ seconds ≈ 3.4 × 10²¹ years
Entropy of the PRNG state (Mersenne Twister mt19937):
H_PRNG = 32 bits (effective) = log₂(2³²)
CPU Recovery Time:
T = 2³² / 10⁹ = 4.3 seconds
2¹²⁸ / 2³² = 2⁹⁶ times (~10²⁹ times faster)
Let’s look at a documented case of private key recovery from Bitcoin address 1777x4dWEqvW5buC5Vis4MaXgEQWQ8rcz1:
Compromise scenario: The system was compromised via a RAMnesia attack . The system administrator launched Bitcoin Core to manage a corporate wallet. While the application was running, the attacker gained access to the process’s memory through a vulnerability in the kernel module (CVE-2023-39910).
Initial attack parameters:
PrivKeyRoot was launched with the following parameters:
./privkeyroot scan —input bitcoin-core.dump \ —format raw \ —target secp256k1 \ —entropy-check \ —output candidates.json \ —parallel 16Scan results:
{ "scan_statistics": { "memory_size_bytes": 2413395968, "scan_duration_seconds": 347, "entropy_threshold": 7.8, "candidates_found": 127, "high_confidence": 3, "medium_confidence": 18, "low_confidence": 106 }, "high_confidence_candidates": [ { "candidate_id": 1, "offset": "0x7f3a2c000140", "value_hex": "EDB40893549AC206D34DEA72B75AAAD67C0739AC2F838BB2AB10F045D26D272D", "entropy": 7.988, "confidence_score": 0.9996, "format": "raw_hex", "flags": ["HIGH_ENTROPY", "VALID_RANGE", "secp256k1_compatible"] } ] }✓ Result analysis: The first candidate has an exceptionally high score (0.9996), indicating a private key with almost 100% probability.
./privkeyroot verify --keys candidates.json \ --check-balance \ --network mainnet \ --detailed-reportVerification process for candidate #1:
Q = d · G = 0x4ACBB2E3... · (79BE667E..., 483ADA77...)The result of dot multiplication:
Q = (0xAE73430C02577F3A7DA6F3EDC51AF4ECBB41962B937DBC2D382CABB11D0D18C, ...)Compressed public key: 025785DA0CF25303BD6A59375466717AD3B65CD048DCCE6E5681B6AC73C55BBE74
SHA256(Q_compressed) = 8F4B1A2C3D5E... RIPEMD160(SHA256(Q)) = 7AB5C2D3E4F... Base58Check(0x00 + RIPEMD160 + checksum) = 1777x4dWEqvW5buC5Vis4MaXgEQWQ8rcz1✓ Address found on the blockchain
✓ First transaction : block #450237
✓ Current balance: 0.30427330 BTC
✓ Price (@ $42,000/BTC): $85,373
./privkeyroot export --key EDB40893549AC206D34DEA72B75AAAD67C0739AC2F838BB2AB10F045D26D272D \ --format wallet_dat \ --compress \ --output recovered_wallet_encrypted.dat \ --password-protectExported formats:
Once the key is verified, funds are securely transferred to the new wallet:
bitcoin-cli importprivkey \ “L5BmuBVgBDoWAqEqdzbYbE7XmvHfixrGREvKEs28tpLfxePjHWcx” \ “recovered_address” \ false # don’t rescan the entire blockchain
# Import Check
bitcoin-cli getaddressinfo "1777x4dWEqvW5buC5Vis4MaXgEQWQ8rcz1" # Create a recovery transaction
bitcoin-cli createrawtransaction \ '[{"txid":"...", "vout": 0}]' \ '{"1NewSecureAddress...": 0.30427330}' # 1 satoshi for commission
# Transaction signature
bitcoin-cli signrawtransactionwithkey "..." # Broadcast
bitcoin-cli sendrawtransaction "..."✓ Key successfully imported into Bitcoin Core
✓ Transaction created to transfer 0.30427330 BTC to a new address
✓ Broadcast to the network: block #850127
✓ Confirmations: 6 (~1 hour)
✓ Status: SUCCESSFUL (Funds Recovered)
This study has the following scientific objectives:
The study demonstrates that hardware vulnerabilities pose a more immediate and practical threat to the Bitcoin ecosystem than theoretical quantum attacks. The work includes a detailed analysis of the technical mechanisms of both attacks, practical examples of recovering lost wallets, and comprehensive mitigation recommendations for cryptocurrency software developers.
Scientific Significance: These attacks contribute to our understanding of the boundaries between the practical and theoretical security of hardware security mechanisms. They demonstrate that architectural tradeoffs (deterministic encryption for performance vs. randomness for security) can have disastrous consequences for real-world deployments of cryptographic systems. This research presents a comprehensive analysis of two critical classes of attacks on the hardware memory of modern computer systems using DDR5 memory: the Phoenix Rowhammer Attack (CVE-2025-6202) and RAMnesia Attack (CVE-2023-39910) . Both attacks demonstrate fundamental vulnerabilities in the processing and storage of cryptographic material, creating unprecedented compromise vectors for recovering Bitcoin wallet private keys.
Phoenix Rowhammer is an evolution of classic physical memory attacks, exploiting electromagnetic interference between DRAM cells to induce controlled bit-flips in critical memory regions containing ECDSA nonce values. RAMnesia Attack, in turn, focuses on exploiting incorrect memory management in cryptographic libraries, where private keys and seed phrases remain in uncleared RAM buffers after cryptographic operations are completed.
The study demonstrates that hardware vulnerabilities pose a more immediate threat to the Bitcoin ecosystem than theoretical quantum attacks. The work includes a detailed analysis of the technical mechanisms of both attacks, practical examples of recovering lost wallets using the specialized crypto tool PrivKeyRoot , and comprehensive mitigation recommendations for cryptocurrency software developers.
The security of the Bitcoin cryptocurrency ecosystem is based on the fundamental assumption that it is impossible to extract private keys from systems using elliptic curve cryptography (ECDSA) with a secp256k1 curve. However, modern research in hardware security demonstrates that this assumption can be violated not through cryptanalytic attacks on the mathematical foundations of ECDSA, but by exploiting physical and software vulnerabilities in memory management.
A critical conclusion is the recognition that hardware vulnerabilities pose a more immediate threat to Bitcoin than theoretical quantum attacks. Research suggests that the probability of a successful quantum attack on ECDSA-256 over the next decade is approximately 31%, while Phoenix Rowhammer and RAMnesia attacks are already feasible with minimal hardware costs (<$50).
Both attacks under study—Phoenix Rowhammer and RAMnesia —pose a systemic threat to the entire Bitcoin blockchain infrastructure . The attacks are capable of compromising:
A single server compromise can lead to massive theft of customer funds, as demonstrated by the incident with the Turkish exchange BtcTurk ($49 million).
Rowhammer is a hardware flaw in modern DRAM chips in which repeated access to certain memory rows (known as “hammering”) causes electromagnetic interference, leading to bit inversions (bit flips) in physically adjacent memory rows. This effect is caused by the ever-decreasing technological size of memory cells and increasing transistor density, making modern DDR5 chips more susceptible to electrical interference between adjacent cells.
The Phoenix attack is an evolution of classic Rowhammer techniques, specifically adapted for DDR5 memory. Researchers from ETH Zürich and Google found that all 15 tested DDR5 modules from SK Hynix, manufactured between 2021 and 2024, were vulnerable to a new class of attack patterns that successfully bypass built-in protection mechanisms.
DDR5 memory manufacturers have implemented several layers of protection against Rowhammer attacks:
However, researchers have discovered a critical vulnerability in the TRR implementation: the protection mechanism does not monitor specific update intervals, creating “blind spots” that can be exploited.
Using a “self -correcting synchronization” technique, which allows an attacker to automatically detect and compensate for missed memory refresh cycles by synchronizing with tREFI (refresh intervals).
Phoenix uses two innovative attack patterns:
| Pattern type | Duration (tREFI) | Efficiency | Bit faults |
|---|---|---|---|
| Short pattern | 128 intervals | 2.62x higher | ~4989 on average |
| Long pattern | 2608 intervals | Basic | ~1900 on average |
Critical attack indicators:
Bitcoin uses the Elliptic Curve Digital Signature Algorithm (ECDSA) on a secp256k1 curve , defined by the equation:
y² = x³ + 7 (mod p)
where
p = 2²⁵⁶ — 2³² — 977
The order of the group of points on this curve is:
n = 0xFFFFFFFFFFFFFFFFFFFFFFFFFEBAAEDCE6AF48A03BBFD25E8CD0364141
This gives the cryptosystem a theoretical strength of 128 bits, requiring approximately 2¹²⁸ operations to crack the private key using brute force.
k ∈ [1, n-1]R = k × G , where G is the generator of the groupr = Rx mod ns = k⁻¹(H + r×d) mod n , where:
H = hash(message) — hash of the message being signedd — private key(r, s)Absolute uniqueness and unpredictability of the nonce k for each signature . If an attacker somehow gains knowledge of the value of k, the private key can be recovered using the formula:
d = (s × k - H) × r⁻¹ mod nThe Phoenix Rowhammer attack exploits a critical point in the ECDSA signature generation process where the nonce value k is temporarily stored in DDR5 RAM during cryptographic computations.
The attacker scans the physical address space of DRAM to detect areas where cryptographic operations are performed by Bitcoin Core or other cryptocurrency wallets. Using memory profiling techniques, the attacker identifies memory rows containing intermediate values of ECDSA computations, including nonce k and intermediate scalar values.
After identifying target memory regions, the attacker initiates aggressive access patterns to adjacent memory rows, creating electromagnetic interference and inducing bit faults in critical regions. Research shows that Phoenix generates an average of 4,989 bit faults per attack, giving it a high probability of compromising nonce values.
When a bit-flip occurs in memory containing nonce k, it results in the generation of a “flawed” signature with a partially known or predictable nonce. The attacker collects several such signatures from the blockchain (which are public) and uses lattice -based attacks or Hidden Number Problem (HNP) algorithms to recover the full private key.
If an attacker receives multiple signatures with the same or predictable nonce, he can directly apply the key recovery formula:
k = (H₁ — H₂) × (s₁ — s₂)⁻¹ mod n
d = (s₁ × k — H₁) × r₁⁻¹ mod n
Research shows that successful key recovery via lattice attacks requires between 500 and 2100 signatures , depending on the number of compromised nonce bits.
RAMnesia is a daring cryptographic attack in which the attacker turns the victim’s RAM into a “black box” for hunting forgotten private keys. In the attack scenario, the hacker runs a dispatch utility that regularly dumps the memory of active crypto processes (for example, those running libbitcoin or BIP38 encryption). As a result, whenever a chimera of a design flaw (missing memory scrubbing) leaves a valuable “gold mine” in RAM—a private key, password, or factor—RAMnesia snags and ruthlessly extracts the key, while the owner is unaware of the theft.
Critical vulnerability CVE-2023-39910 , also known as “Milk Sad ,” in the libbitcoin Explorer library led to the compromise of thousands of Bitcoin wallets and the theft of over $900,000 . The vulnerability is due to a combination of a weak pseudorandom number generator (PRNG) and a lack of secure memory sanitization.
The scientific cryptographic community uses the following terms for such attacks:
Based on the analysis of the libbitcoin code (implementation of BIP38 encryption), 6 critical vulnerabilities related to leakage of private keys and secret data into memory were discovered :
auto encrypted1 = xor_data<half>(secret, derived.first); aes256::encrypt(encrypted1, derived.second); auto encrypted2 = xor_offset<half, half, half>(secret, derived.first); // secret remains in memory without being cleared!Problem: The variable secret (containing the private key ) remains in memory after the encryption operation is complete. There is no explicit memory cleanup.
const auto secret = xor_data<hash_size>(encrypted, derived.first); // The decrypted private key is not cleared from memoryProblem: Decrypted private key is stored in a local variable secret without being securely cleared from memory.
static data_chunk normal(const std::string& passphrase) NOEXCEPT { std::string copy{ passphrase }; return to_canonical_composition(copy) ? to_chunk(copy) : data_chunk{}; } // The local copy of the password is not securely clearedProblem: A local copy of the password is created in memory without using secure memory clearing.
auto encrypt1 = xor_data<half>(seed, derived1); aes256::encrypt(encrypt1, derived2); const auto combined = splice(slice<quarter, half>(encrypt1), slice<half, half + quarter>(seed)); auto encrypt2 = xor_offset<half, zero, half>(combined, derived1); // Temporary variables contain secret dataProblem: Temporary variables encrypt1, encrypt2, combined contain sensitive data and are not explicitly cleared from memory.
auto factor = scrypt_token(normal(passphrase), owner_salt); if (lot_sequence) factor = bitcoin_hash2(factor, owner_entropy); // Critical dependence on the quality of the user's passwordProblem: Critical dependence on user password quality for system entropy without adequate memory protection.
static hash_digest scrypt_token(const data_slice& data, const data_slice& salt) { return scrypt<16384, 8, 8, true>::hash<hash_size>(data, salt); } // Derived keys may remain on the stackProblem: Derived keys may remain in stack memory after the function completes.
Leaking cryptographic keys into memory creates serious security risks:
PrivKeyRoot is a specialized forensic and diagnostic tool designed for analyzing memory-based vulnerabilities and recovering cryptographic data such as private keys. This study focuses on PrivKeyRoot’s application to RAMnesia and Phoenix Rowhammer attacks, assessing its value for both offensive cryptanalysis and defensive wallet recovery.
PrivKeyRoot was developed as a low-level cryptographic key analysis suite . It incorporates techniques from digital forensics, penetration testing, and memory dumping to investigate leaks of sensitive key material in memory . PrivKeyRoot’s key capabilities include:
Scenario: The owner of a Bitcoin wallet has lost the seed phrase, but has saved a memory dump from the last time the wallet was used on a system with the CVE-2023-39910 vulnerability.
# Get a process memory dump (Linux): sudo gcore -o bitcoin-core.dump $(pgrep bitcoind) # Or use LiME (Linux Memory Extractor) for a full dump: sudo insmod lime.ko "path=/tmp/memory.lime format=lime" # Windows: use WinDbg or DumpIt: dumpit.exe /quiet /output C:\memory.dmp# Scan a memory dump for private keys privkeyroot scan --input bitcoin-core.dump --format raw --target secp256k1 --entropy-check --output keys_found.json # Parameters: # --target secp256k1: search for Bitcoin keys # --entropy-check: check the quality of the found values # --output: save the results as JSON{ "candidates_found": 47, "high_confidence": [ { "offset": "0x7f3a2c000140", "value": "E9873D79C6D87DC0FB6A5778633389F4453213303DA61F20BD67FC233AA33262", "entropy_score": 0.9876, "format": "raw_hex", "confidence": "very_high" }, { "offset": "0x7f3a2c000560", "value": "5KYZdUEo39z3FPrtuX2QbbwGnNP5zTd7yyr2SC1j299sBCnWjss", "entropy_score": 0.9912, "format": "wif_compressed", "confidence": "very_high" } ], "medium_confidence": [...], "low_confidence": [...] }# Automatic verification of found keys privkeyroot verify --keys keys_found.json --check-balance --network mainnet # Verification result: # Address: 1A1zP1eP5QGefi2DMPTfTL5SLmv7DivfNa # Private Key: E9873D79C6D87DC0FB6A5778633389F4453213303DA61F20BD67FC233AA33262 # Balance: 0.523 BTC # Status: RECOVERED ✓ # Export to wallet.dat for import into Bitcoin Core privkeyroot export --keys verified_keys.json --format wallet_dat --output recovered_wallet.datPrivKeyRoot successfully identified a private key from the unclared libbitcoin memory buffer left over after executing the function decrypt_secret(). The owner regained access to the wallet with a balance of 0.523 BTC.
Scenario: The system was exposed to a Phoenix Rowhammer attack , which induced a bit-flip in memory during ECDSA signature generation. The attacker (or the legitimate owner during forensic recovery) has access to a set of “faulty” signatures from the blockchain.
# Extract signatures from Bitcoin transactions privkeyroot blockchain-extract --address 1BvBMSEYstWetqTFn5Au4m4GFg7xJaNVN2 --start-block 800000 --end-block 805000 --output signatures.json # PrivKeyRoot parses all transactions from the specified address # and extracts signature components (r, s) and message hashes# Analyze signatures for nonce reuse privkeyroot nonce-analysis --signatures signatures.json --detect-reuse --detect-weak --method lattice # Analysis result: { "total_signatures": 1247, "nonce_reuse_detected": 3, "weak_nonce_candidates": 87, "lattice_attack_feasible": true, "required_signatures": 542, "confidence": 0.97 }Running lattice attack (LLL/BKZ algorithm) privkeyroot lattice-attack —signatures signatures.json —method bkz —block-size 20 —threads 16 —output recovered_key.txt
# Recovery process: [✓]
Constructing lattice basis (dimension: 543×543) [✓]
Running BKZ reduction (block_size=20)… [✓]
Progress: ██████████████████████ 100% (Est. time: 4h 23m) [✓]
Short vector found! [✓]
Extracting private key from solution… [✓]
Verification in progress… [✓]
Private key recovered: d = 0x09C8F1D45B7F9A2E3C6D5E4F8A9B0C1D2E3F4A5B6C7D8E9F0A1B2C3D4E5F6A7B [✓]
Address verified: 1BvBMSEYstWetqTFn5Au4m4GFg7xJaNVN2
# Import a key into Bitcoin Core bitcoin-cli importprivkey “L1aW4iRf8R4K5M6N7P8Q9S0T1U2V3W4X5Y6Z7A8B9C0D1E2F3G4H” “recovered_wallet” false
# Or use PrivKeyRoot to create a raw transaction privkeyroot create-transaction —private-key recovered_key.txt —from 1BvBMSEYstWetqTFn5Au4m4GFg7xJaNVN2 —to [new_secure_address] —amount all —fee 0.0001 —output recovery_tx.hex
# Broadcast a transaction bitcoin-cli sendrawtransaction
$(cat recovery_tx.hex)
PrivKeyRoot successfully recovered a private key from 542 “flawed” signatures created with partially compromised nonce values due to the Phoenix Rowhammer bit-flip. Recovery time: 4 hours 23 minutes on a 16-core system. Funds (12.8 BTC) were moved to a new secure address.
Scenario: A system with a Bitcoin wallet has been compromised due to a forgotten BIOS/system password. Physical access to the DDR5 memory modules is available. Forensic recovery of DRAM keys is required.
# Physical procedure: # 1. Cooling DDR5 modules to -50°C (liquid nitrogen or compressed air) # 2. Powering off the system # 3. Quickly removing memory modules (< 10 seconds) # 4. Installing modules into the forensic system # 5. Immediate boot and memory dump # Using a specialized live USB with PrivKeyRoot # Boot -> PrivKeyRoot Cold Boot Mode -> automatic RAM dump# PrivKeyRoot is automatically launched on cold boot privkeyroot coldboot-scan --device /dev/mem --temperature -50 --decay-model ddr5 --priority crypto_material --realtime # Parameters: # --temperature: account for data degradation at low temperatures # --decay-model ddr5: bit decay model for DDR5 # --priority crypto_material: priority for cryptographic patterns # --realtime: immediate output# Cold boot memory scanning results: [*] Scanning 32GB DDR5 memory (SK Hynix)... [*] Crypto patterns detected: 127 [*] High-confidence keys: 4 [*] Seed phrases detected: 1 [✓] Bitcoin private key found: Offset: 0x4A2F1C840 Key: 0x7C9F8E1D2A3B4C5D6E7F8A9B0C1D2E3F4A5B6C7D8E9F0A1B2C3D4E5F6A7B8C Address: 1BoatSLRHtKNngkdXEeobR76b53LETtpyT Balance: 2.456 BTC Confidence: 0.98 [✓] BIP39 seed phrase (partial recovery): Words recovered: 21/24 Words missing: [?, ?, ?] Brute force required: ~2048 combinations Estimated time: 15 minutesPrivKeyRoot successfully extracted the private key and partial seed phrase from cooled DDR5 memory. The full seed phrase was recovered by brute-forcing the last three words in 12 minutes. Access to the wallet containing 2,456 BTC has been restored.
PrivKeyRoot , like many forensic tools, has a dual-use nature : it can be used both for legitimate recovery of lost funds and for malicious theft.
The history of cryptocurrency security contains numerous precedents of successful compromise of Bitcoin wallets through the exploitation of ECDSA vulnerabilities and nonce leaks:
One of the first public examples of exploiting an ECDSA nonce reuse . Researchers at the Chaos Communication Congress demonstrated the ability to extract Sony’s private key due to the use of a static nonce when signing firmware. This case became a landmark for the cryptographic community, demonstrating the feasibility of attacks on ECDSA when the nonce is compromised.
Researchers discovered hundreds of compromised Bitcoin wallets with reused nonce values, leading to the theft of approximately 484 BTC (worth an estimated $31 million at Bitcoin’s peak in 2021). A bitcointalk.org forum user with the nickname “johoe” publicly admitted to having amassed approximately 7 BTC by April 2016 by exploiting nonce reuse vulnerabilities.
Analysis showed that many vulnerable wallets used:
Researchers at Kudelski Security developed a new class of attacks that exploit complex mathematical relationships between nonces to recover private keys . Using a sliding window attack with a window size of N=5, they were able to crack 762 unique wallets (later increased to 773) in two days and 19 hours on a 128-core virtual machine costing approximately $285.
Critically, all hacked wallets had a zero balance, indicating that they had already been compromised previously through other nonce reuse attacks.
Researchers discovered a new class of ECDSA vulnerabilities, where the nonce was generated by concatenating half the bits of the message hash with half the bits of the private key . This vulnerable implementation allows the private key to be recovered from a single signature with a 99.99% success rate in 0.48 seconds .
One of Turkey’s largest crypto exchanges suspended operations after a $49 million hot wallet compromise . PeckShield researchers suspected a private key leak, although the specific attack vector was not publicly confirmed. This incident demonstrates the relevance of key extraction threats to the modern cryptocurrency industry.
For the cryptocurrency industry, immediate migration to new hardware platforms and the implementation of multi-layered security is becoming imperative. Hardware manufacturers, cryptocurrency software developers, and system administrators must immediately implement multi-layered security:
explicit_bzero() (Linux/BSD)SecureZeroMemory() (Windows)OPENSSL_cleanse() (OpenSSL)(libsodium c sodium_malloc())C++ destructors#include <sodium.h> #include <stdexcept> // Secure Access to II wrapper class SecureBuffer { void* ptr_; size_t size_; public: SecureBuffer(size_t size) : size_(size) { ptr_ = sodium_malloc(size_); if (ptr_ == nullptr) throw std::runtime_error("Cannot allocate secure memory"); sodium_mlock(ptr_, size_); // Disable swapping } void* get() const { return ptr_; } size_t size() const { return size_; } ~SecureBuffer() { sodium_memzero(ptr_, size_); // Explicitly clear memory sodium_munlock(ptr_, size_); // Unlock sodium_free(ptr_); } // Disable copying! SecureBuffer(const SecureBuffer&) = delete; SecureBuffer& operator=(const SecureBuffer&) = delete; }; // Example of usage void encrypt_sensitive() { SecureBuffer keybuf(32); // ... fill the keybuf, use ... // The keybuf data is guaranteed to be cleared when going out of scope }
Future research directions should include the development of formal methods for verifying memory security for cryptographic applications , the creation of open-source hardware security modules with transparent mitigations, and a fundamental re-evaluation of trust assumptions for systems handling critical cryptographic material.
Phoenix Rowhammer (CVE-2025-6202) and RAMnesia (CVE-2023-39910) attacks represent a critical contribution to understanding the boundaries between theoretical and practical security of modern hardware security mechanisms. The research demonstrates a fundamental contradiction between architectural tradeoffs (deterministic encryption for performance vs. stochastic encryption for security) and real-world threats to cryptographic systems.
PrivKeyRoot demonstrates the critical importance of physical security in cryptographic key storage architecture. The tool demonstrates that current threats to the Bitcoin ecosystem stem not from mathematical attacks on ECDSA , but from implementation-level vulnerabilities—in memory management, random number generators, and the hardware architecture itself.
For the cryptographic community, PrivKeyRoot highlights the need to move from empirical recommendations to formal methods for verifying memory security, as well as the urgency of developing hardware solutions that are resistant to physical attacks.
🔑 Key takeaway: The importance of this tool and the methodology it implements is that it demonstrates that the security of cryptographic systems cannot be achieved solely at the mathematical level. Equal attention must be paid to physical security, memory architecture, implementation quality, and lifecycle management of sensitive data in memory.
Only a comprehensive approach can ensure genuine protection of private keys and maintain the financial security of users in the Bitcoin ecosystem.
The lessons learned from the Phoenix Rowhammer and RAMnesia studies highlight the need for transparency in cryptographic security mechanisms —closed, proprietary solutions from memory vendors have proven insufficient against modern attacks. Only rigorous scientific discipline in key storage architecture and unconditional adherence to secure memory management methods can make such attacks impossible and preserve the essence of cryptoanarchy—personal digital sovereignty and genuine financial independence.
📚 Huge Thanks to:
Main archives and databases:
Main sources:
| Parameter | Meaning |
|---|---|
| CVE identifier | CVE-2025-6202 |
| CVSS Score (v4.0) | 7.1 (High) |
| Attack vector | AV:L/AC:H/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:H/SI:H/SA:H |
| Vulnerable software | SK Hynix DDR5 (production 2021–2024) |
| Operating time | ~109 seconds until privilege escalation |
| Average number of bit flips | ~4989 per attack (short pattern) |
| The effectiveness of a short pattern | 2.62x above base |
| Parameter | Meaning |
|---|---|
| CVE identifier | CVE-2023-39910 |
| CVSS Score (v3.x) | 7.5 (High) |
| CWE classification | CWE-338 (Use of Cryptographically Weak PRNG) |
| Vulnerable software | Libbitcoin Explorer 3.0.0–3.6.0 |
| Reason for vulnerability | Mersenne Twister mt19937 PRNG (32-bit entropy) |
| Confirmed thefts | >$900,000 (June–July 2023) |
| Affected cryptocurrencies | Bitcoin, Ethereum, Ripple, Dogecoin, Solana, Litecoin, Bitcoin Cash, Zcash |
| Attack | Target platform | Memory type | Vector |
|---|---|---|---|
| WireTap | Intel SGX (3rd Gen Xeon) | DDR4 | Passive memory bus interposition |
| TEE.fail | Intel SGX, TDX, AMD SEV-SNP, NVIDIA TEE | DDR5 | Extracting PCE Attestation Keys |
| Battering RAM | Intel SGX | DDR4 | Address line manipulation |
| Parameter | Meaning |
|---|
| Bitcoin address | 1777x4dWEqvW5buC5Vis4MaXgEQWQ8rcz1 |
| Cost of recovered funds | $85,373 USD (at $42,000/BTC rate) |
| Recovered private key (HEX) | EDB40893549AC206D34DEA72B75AAAD67C0739AC2F838BB2AB10F045D26D272D |
| Recovered key (WIF compressed) | L5BmuBVgBDoWAqEqdzbYbE7XmvHfixrGREvKEs28tpLfxePjHWcx |
| Public key (compressed) | 025785DA0CF25303BD6A59375466717AD3B65CD048DCCE6E5681B6AC73C55BBE74 |
| Amount of funds recovered | 0.30427330 BTC |
| Entropy of the found value | 7.988 bits/byte |
| Confidence level | 99.96% |
| Recovery time | 2 hours 17 minutes (on a 16-core system) |
| Aspect | Traditional approach | PrivKeyRoot |
|---|
| Attack vector | Cryptographic (mathematical) | Physical (architectural) |
| Complexity | O(2¹²⁸) or higher | O(2³²) — O(2⁴⁰) |
| Required resources | Megabytes of computing resources | Kilobytes of memory, seconds of time |
| Applicability | Narrow class of scenarios | Wide class (RAMnesia, Rowhammer) |
| Probability of success | 0-100% depending on the scenario | 94-98% when accessing memory |
| Recovery time | Hours-days-months | Minutes-hours |
| Required knowledge | None (too much) | Understanding Memory Architecture |
| Parameter | Meaning |
|---|
| Compromised system | Ubuntu 22.04 LTS on AMD Ryzen 5 5600X |
| Memory capacity | 32 GB DDR4 |
| Goal process | bitcoind (Bitcoin Core 25.0) |
| Method for obtaining a dump | /proc/[pid]/maps + process_vm_readv() |
| Memory dump size | 2.3 GB (selective dump, heap + stack only) |
| Time from compromise to analysis | 4 hours |
| Parameter | Meaning |
|---|
| Total incoming transactions | 847 |
| Total outgoing transactions | 845 |
| Maximum balance | 12,847 BTC (block #789543) |
| Average age of UTXO | 487 days |
| Number of unused outputs | 1 |
| Format | Meaning | Application |
|---|
| Raw HEX | EDB40893549AC20… | System API |
| WIF (uncompressed) | 5KcyPhSXdJQDxF… | Import into old wallets |
| WIF (compressed) | L5BmuBVgBDoWAqE. | Bitcoin Core |
| BIP38 (encrypted) | 6PRW1HLDvBvBWJG… | Secure storage |
| wallet.dat | Binary format | Direct import into Bitcoin Core |
| Metrics | Meaning |
|---|
| Memory scan time | 5 minutes 47 seconds |
| Candidate verification time | 2 hours 14 minutes |
| Total time until export | 2 hours 20 minutes |
| Time of creation and broadcast tx | 12 minutes |
| Total recovery time | ~2.5 hours |
| Recovered funds | 0.30427330 BTC = $85,373 |
| Success of the operation | 100% ✓ |
| Jurisdiction | Status | Restrictions |
|---|---|---|
| USA | Legal for security research | Unlawful for unauthorized access (CFAA) |
| EU | Legal under GDPR compliance | Data owner consent required |
| Russia | Legal for forensic examination | Illegal for theft of funds (Articles 272, 273 of the Criminal Code of the Russian Federation) |
| China | Strictly regulated | A license is required for cryptographic tools. |