CVE-2019-19378
📋 TL;DR
This vulnerability in the Linux kernel allows an attacker to cause a slab-out-of-bounds write by mounting a specially crafted btrfs filesystem image. This can lead to kernel memory corruption, potentially resulting in system crashes or privilege escalation. Systems running affected Linux kernel versions with btrfs support are vulnerable.
💻 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 leading to denial of service, or privilege escalation to root if memory corruption is exploited for arbitrary code execution.
Likely Case
System crash or kernel panic causing denial of service when mounting malicious btrfs images.
If Mitigated
No impact if systems don't mount untrusted btrfs filesystem images or have patched kernels.
🎯 Exploit Status
Exploit requires ability to mount crafted btrfs filesystem image on target system.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Linux kernel 5.0.22 and later
Vendor Advisory: https://security.netapp.com/advisory/ntap-20200103-0001/
Restart Required: Yes
Instructions:
1. Update Linux kernel to version 5.0.22 or later. 2. Use distribution package manager: 'sudo apt update && sudo apt upgrade' (Debian/Ubuntu) or 'sudo yum update kernel' (RHEL/CentOS). 3. Reboot system after update.
🔧 Temporary Workarounds
Disable btrfs module
linuxPrevent loading of btrfs kernel module to block exploitation
echo 'blacklist btrfs' | sudo tee /etc/modprobe.d/blacklist-btrfs.conf
sudo rmmod btrfs
Restrict filesystem mounting
linuxLimit who can mount filesystems using mount permissions
sudo chmod 700 /bin/mount
sudo chown root:root /bin/mount
🧯 If You Can't Patch
- Restrict access to mount command and prevent mounting of untrusted filesystem images
- Implement strict access controls on systems that must mount btrfs filesystems
🔍 How to Verify
Check if Vulnerable:
Check kernel version: 'uname -r' and verify if it's 5.0.21 or other vulnerable version with btrfs supportCheck Version:
uname -rVerify Fix Applied:
Check kernel version after update: 'uname -r' should show 5.0.22 or later📡 Detection & Monitoring
Log Indicators:
- Kernel panic messages in /var/log/kern.log or dmesg
- Filesystem mount failures for btrfs
Network Indicators:
- Unusual network transfers of filesystem image files
SIEM Query:
source="kern.log" AND "kernel panic" OR "btrfs" AND "mount"