CVE-2024-35871
📋 TL;DR
This CVE-2024-35871 vulnerability in the Linux kernel's RISC-V architecture allows kernel pointer leakage to user space. It affects systems running Linux on RISC-V hardware where user_mode_helper threads can expose kernel memory addresses through various tracing mechanisms. This information disclosure could aid attackers in bypassing kernel address space layout randomization (KASLR).
💻 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 →⚠️ Risk & Real-World Impact
Worst Case
Kernel address disclosure enabling KASLR bypass, potentially leading to more reliable kernel exploitation and privilege escalation attacks.
Likely Case
Information disclosure of kernel pointers that could be used as part of a multi-stage attack chain to bypass security mitigations.
If Mitigated
Limited information disclosure with minimal practical impact if proper kernel hardening and access controls are in place.
🎯 Exploit Status
Exploitation requires local access and ability to interact with user_mode_helper threads or use tracing mechanisms. Multiple exploitation vectors mentioned in description but no confirmed exploits.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Patches available in stable kernel trees (commits referenced in CVE)
Vendor Advisory: https://git.kernel.org/stable/c/00effef72c98294edb1efa87ffa0f6cfb61b36a4
Restart Required: Yes
Instructions:
1. Update to latest stable Linux kernel version containing the fix. 2. For RISC-V specific distributions, apply kernel patches from stable tree. 3. Reboot system to load patched kernel.
🔧 Temporary Workarounds
Disable user_mode_helper tracing
linuxRestrict access to tracing mechanisms that could expose kernel pointers
sysctl -w kernel.perf_event_paranoid=3
sysctl -w kernel.yama.ptrace_scope=2
Enable kernel lockdown
linuxUse kernel lockdown mode to restrict access to kernel memory
echo lockdown > /sys/kernel/security/lockdown
🧯 If You Can't Patch
- Implement strict access controls to limit who can use ptrace and performance monitoring tools
- Monitor for unusual tracing activity or attempts to access kernel memory addresses from user space
🔍 How to Verify
Check if Vulnerable:
Check kernel version and architecture: uname -a should show RISC-V architecture. Review if patches from stable tree are applied.Check Version:
uname -rVerify Fix Applied:
Verify kernel version includes the fix commits: git log --oneline | grep -E '(00effef72c98294edb1efa87ffa0f6cfb61b36a4|9abc3e6f1116adb7a2d4fbb8ce20c37916976bf5|d14fa1fcf69db9d070e75f1c4425211fa619dfc8|d8dcba0691b8e42bddb61aab201e4d918a08e5d9|dff6072124f6df77bfd36951fbd88565746980ef)'📡 Detection & Monitoring
Log Indicators:
- Unusual ptrace activity
- Performance monitoring events accessing kernel addresses
- Attempts to read /proc/*/task/*/syscall on user_mode_helper threads
Network Indicators:
- None - local vulnerability only
SIEM Query:
process.name:ptrace OR process.name:perf AND target.process.name contains 'user_mode_helper'🔗 References
- https://git.kernel.org/stable/c/00effef72c98294edb1efa87ffa0f6cfb61b36a4
- https://git.kernel.org/stable/c/9abc3e6f1116adb7a2d4fbb8ce20c37916976bf5
- https://git.kernel.org/stable/c/d14fa1fcf69db9d070e75f1c4425211fa619dfc8
- https://git.kernel.org/stable/c/d8dcba0691b8e42bddb61aab201e4d918a08e5d9
- https://git.kernel.org/stable/c/dff6072124f6df77bfd36951fbd88565746980ef
- https://git.kernel.org/stable/c/f6583444d7e78dae750798552b65a2519ff3ca84
- https://git.kernel.org/stable/c/00effef72c98294edb1efa87ffa0f6cfb61b36a4
- https://git.kernel.org/stable/c/9abc3e6f1116adb7a2d4fbb8ce20c37916976bf5
- https://git.kernel.org/stable/c/d14fa1fcf69db9d070e75f1c4425211fa619dfc8
- https://git.kernel.org/stable/c/d8dcba0691b8e42bddb61aab201e4d918a08e5d9
- https://git.kernel.org/stable/c/dff6072124f6df77bfd36951fbd88565746980ef
- https://git.kernel.org/stable/c/f6583444d7e78dae750798552b65a2519ff3ca84
- https://lists.debian.org/debian-lts-announce/2024/06/msg00017.html
