CVE-2024-49988
📋 TL;DR
This is a use-after-free vulnerability in the Linux kernel's ksmbd SMB server module. Attackers could potentially exploit this to cause kernel crashes (denial of service) or possibly execute arbitrary code. Systems running affected Linux kernel versions with ksmbd enabled 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 →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 →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 system crash and denial of service, with potential for arbitrary code execution in kernel context.
Likely Case
System instability, kernel crashes, and denial of service affecting SMB file sharing functionality.
If Mitigated
Limited impact if ksmbd is disabled or not in use, with potential for isolated crashes in SMB service.
🎯 Exploit Status
Exploitation requires sending specific SMB oplock break requests to trigger the use-after-free condition.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Patches available in kernel stable branches via provided git commits
Vendor Advisory: https://git.kernel.org/stable/c/18f06bacc197d4ac9b518ad1c69999bc3d83e7aa
Restart Required: Yes
Instructions:
1. Update Linux kernel to patched version from distribution vendor. 2. Rebuild kernel if using custom kernel with patches from provided git commits. 3. Reboot system to load new kernel.
🔧 Temporary Workarounds
Disable ksmbd module
linuxPrevent loading of vulnerable ksmbd kernel module
echo 'blacklist ksmbd' >> /etc/modprobe.d/blacklist-ksmbd.conf
rmmod ksmbd
Restrict SMB network access
linuxLimit exposure by restricting network access to SMB ports
iptables -A INPUT -p tcp --dport 445 -j DROP
iptables -A INPUT -p tcp --dport 139 -j DROP
🧯 If You Can't Patch
- Disable ksmbd module if not required for operations
- Implement network segmentation to isolate SMB services from untrusted networks
🔍 How to Verify
Check if Vulnerable:
Check if ksmbd module is loaded: lsmod | grep ksmbdCheck Version:
uname -rVerify Fix Applied:
Check kernel version after update and verify ksmbd module version matches patched kernel📡 Detection & Monitoring
Log Indicators:
- Kernel panic messages in /var/log/kern.log or dmesg
- Unexpected ksmbd process crashes
Network Indicators:
- Unusual SMB oplock break request patterns
- Multiple connection attempts to SMB ports
SIEM Query:
source="kernel" AND ("panic" OR "Oops") AND "ksmbd"