CVE-2023-3611
📋 TL;DR
This CVE-2023-3611 is an out-of-bounds write vulnerability in the Linux kernel's QFQ scheduler component that allows local attackers to escalate privileges. It affects Linux systems with the QFQ scheduler enabled, potentially allowing attackers to gain root access from an unprivileged local account.
💻 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 →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 →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
Full system compromise with root privileges, allowing complete control over the affected system, data theft, and lateral movement within the network.
Likely Case
Local privilege escalation to root, enabling attackers to install malware, modify system configurations, or access sensitive data.
If Mitigated
Limited impact if proper access controls, SELinux/AppArmor, and least privilege principles are enforced, though kernel compromise remains serious.
🎯 Exploit Status
Requires local access and knowledge of kernel exploitation techniques. No public exploit code has been disclosed as of the advisory dates.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Linux kernel with commit 3e337087c3b5805fe0b8a46ba622a962880b5d64
Vendor Advisory: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=3e337087c3b5805fe0b8a46ba622a962880b5d64
Restart Required: Yes
Instructions:
1. Update Linux kernel to version containing commit 3e337087c3b5805fe0b8a46ba622a962880b5d64. 2. For Debian systems: apt update && apt upgrade linux-image-$(uname -r). 3. Reboot the system to load the new kernel.
🔧 Temporary Workarounds
Disable QFQ scheduler
linuxRemove or disable the QFQ scheduler module if not required
rmmod sch_qfq
echo 'blacklist sch_qfq' > /etc/modprobe.d/disable-qfq.conf
🧯 If You Can't Patch
- Implement strict access controls and limit local user accounts
- Enable SELinux/AppArmor with restrictive policies and monitor for privilege escalation attempts
🔍 How to Verify
Check if Vulnerable:
Check kernel version and if QFQ module is loaded: uname -r && lsmod | grep qfqCheck Version:
uname -rVerify Fix Applied:
Verify kernel version includes the fix commit: grep -q '3e337087c3b5805fe0b8a46ba622a962880b5d64' /proc/version_signature || echo 'Check kernel changelog'📡 Detection & Monitoring
Log Indicators:
- Kernel panic logs
- System crash dumps
- Unusual privilege escalation in audit logs
Network Indicators:
- None - this is a local exploit
SIEM Query:
source="kernel" AND ("panic" OR "Oops" OR "general protection fault") OR source="audit" AND "privilege" AND "escalation"🔗 References
- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=3e337087c3b5805fe0b8a46ba622a962880b5d64
- https://kernel.dance/3e337087c3b5805fe0b8a46ba622a962880b5d64
- https://lists.debian.org/debian-lts-announce/2023/10/msg00027.html
- https://lists.debian.org/debian-lts-announce/2024/01/msg00004.html
- https://security.netapp.com/advisory/ntap-20230908-0002/
- https://www.debian.org/security/2023/dsa-5480
- https://www.debian.org/security/2023/dsa-5492
- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=3e337087c3b5805fe0b8a46ba622a962880b5d64
- https://kernel.dance/3e337087c3b5805fe0b8a46ba622a962880b5d64
- https://lists.debian.org/debian-lts-announce/2023/10/msg00027.html
- https://lists.debian.org/debian-lts-announce/2024/01/msg00004.html
- https://security.netapp.com/advisory/ntap-20230908-0002/
- https://www.debian.org/security/2023/dsa-5480
- https://www.debian.org/security/2023/dsa-5492
