CVE-2024-49869
📋 TL;DR
This CVE describes a buffer overflow detection issue in the Linux kernel's btrfs send functionality. The vulnerability occurs when copying path names to cache entries, where incorrect array size annotations cause false positive overflow warnings. This affects systems using btrfs filesystems with the send feature enabled.
💻 Affected Systems
- Linux kernel
📦 What is this software?
Linux Kernel by Linux
The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...
Learn more about Linux Kernel →⚠️ Risk & Real-World Impact
Worst Case
Kernel panic or system crash due to false positive overflow detection, leading to denial of service and potential data corruption in btrfs operations.
Likely Case
System instability with kernel warnings and potential crashes during btrfs send operations, disrupting backup and snapshot operations.
If Mitigated
Minor performance impact with proper kernel configuration and monitoring.
🎯 Exploit Status
This is a detection logic issue causing false positives, not a traditional buffer overflow vulnerability. Exploitation would require triggering specific btrfs send operations.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Linux kernel with commits 843738ede6cb8b959fb22591fcbabe8b456d7216 and 96c6ca71572a3556ed0c37237305657ff47174b7
Vendor Advisory: https://git.kernel.org/stable/c/843738ede6cb8b959fb22591fcbabe8b456d7216
Restart Required: Yes
Instructions:
1. Update Linux kernel to version containing the fix commits. 2. For distributions: Use package manager (apt/yum/dnf) to update kernel. 3. Reboot system to load new kernel.
🔧 Temporary Workarounds
Disable btrfs send operations
linuxPrevent use of btrfs send functionality to avoid triggering the issue
# Monitor and restrict btrfs send usage
# Consider alternative backup methods
Disable kernel fortification warnings
linuxSuppress the false positive warnings (not recommended for production)
# Add kernel parameter: fortify_source=0
# Edit /etc/default/grub and add to GRUB_CMDLINE_LINUX
🧯 If You Can't Patch
- Monitor system logs for btrfs-related warnings and crashes
- Implement strict access controls to limit btrfs send operations to trusted users only
🔍 How to Verify
Check if Vulnerable:
Check kernel version and if btrfs send operations trigger warnings: dmesg | grep -i 'strcpy.*detected buffer overflow'Check Version:
uname -rVerify Fix Applied:
After patching, verify no warnings appear during btrfs send operations and check kernel contains fix commits📡 Detection & Monitoring
Log Indicators:
- Kernel warnings about strcpy buffer overflow
- btrfs-related crash reports in system logs
- WARNING: CPU: ... at __fortify_report+0x45/0x50
Network Indicators:
- None - this is a local filesystem issue
SIEM Query:
source="kernel" AND "strcpy: detected buffer overflow" AND "btrfs"