CVE-2018-25015
📋 TL;DR
This CVE describes a use-after-free vulnerability in the Linux kernel's SCTP (Stream Control Transmission Protocol) implementation. Attackers can potentially exploit this to cause denial of service, execute arbitrary code, or escalate privileges. Systems running Linux kernels before version 4.14.16 with SCTP enabled are affected.
💻 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
Full system compromise with kernel-level code execution leading to complete system takeover, data exfiltration, or persistent backdoor installation.
Likely Case
Kernel panic or system crash causing denial of service, potentially requiring physical or remote console access to restore functionality.
If Mitigated
Limited impact if SCTP is disabled or systems are isolated, with potential for service disruption but no privilege escalation.
🎯 Exploit Status
Syzkaller fuzzer discovered this bug, and proof-of-concept code exists in the references. Exploitation requires SCTP access and knowledge of kernel internals.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Linux kernel 4.14.16 and later
Vendor Advisory: https://cdn.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.14.16
Restart Required: Yes
Instructions:
1. Update kernel to version 4.14.16 or later using your distribution's package manager. 2. Reboot the system to load the new kernel. 3. Verify the kernel version after reboot.
🔧 Temporary Workarounds
Disable SCTP kernel module
linuxPrevent loading of the vulnerable SCTP kernel module
echo 'install sctp /bin/true' >> /etc/modprobe.d/disable-sctp.conf
rmmod sctp
Block SCTP network traffic
linuxUse firewall rules to block SCTP protocol traffic
iptables -A INPUT -p sctp -j DROP
iptables -A OUTPUT -p sctp -j DROP
🧯 If You Can't Patch
- Disable SCTP protocol support in kernel configuration and reboot
- Implement network segmentation to isolate systems with SCTP requirements
🔍 How to Verify
Check if Vulnerable:
Check if SCTP module is loaded: lsmod | grep sctp AND check kernel version: uname -rCheck Version:
uname -rVerify Fix Applied:
Verify kernel version is 4.14.16 or later: uname -r AND confirm SCTP is either disabled or patched📡 Detection & Monitoring
Log Indicators:
- Kernel panic messages in /var/log/messages or dmesg
- SCTP-related crash reports
- Unexpected system reboots
Network Indicators:
- Unusual SCTP traffic patterns
- SCTP connection attempts from unexpected sources
SIEM Query:
source="kernel" AND ("panic" OR "Oops" OR "general protection fault") AND "sctp"🔗 References
- https://cdn.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.14.16
- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=a0ff660058b88d12625a783ce9e5c1371c87951f
- https://security.netapp.com/advisory/ntap-20210720-0002/
- https://sites.google.com/view/syzscope/warning-held-lock-freed
- https://syzkaller.appspot.com/bug?id=a8d38d1b68ffc744c53bd9b9fc1dbd6c86b1afe2
- https://cdn.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.14.16
- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=a0ff660058b88d12625a783ce9e5c1371c87951f
- https://security.netapp.com/advisory/ntap-20210720-0002/
- https://sites.google.com/view/syzscope/warning-held-lock-freed
- https://syzkaller.appspot.com/bug?id=a8d38d1b68ffc744c53bd9b9fc1dbd6c86b1afe2
