CVE-2024-46774
📋 TL;DR
This CVE describes a Spectre v1 vulnerability in the Linux kernel's RTAS (Run-Time Abstraction Services) system call implementation on PowerPC architecture. Attackers could exploit this to read kernel memory contents, potentially exposing sensitive information. Systems running affected Linux kernel versions on PowerPC hardware 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 memory disclosure leading to privilege escalation, credential theft, or complete system compromise through information disclosure that enables further attacks.
Likely Case
Information disclosure of kernel memory contents, potentially exposing sensitive data like encryption keys, passwords, or other system information.
If Mitigated
Limited impact due to speculative execution barriers preventing successful exploitation, though some information leakage might still occur.
🎯 Exploit Status
Exploitation requires local access and knowledge of Spectre v1 exploitation techniques. The vulnerability is in a system call interface that requires user privileges to access.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Patches available in stable kernel trees (commits: 0974d03eb479384466d828d65637814bee6b26d7, 1f1feff02e9da0dd0cdb195c428c42b5f9b6c771, 68d8156480940b79227d58865ec5d2947b9384a8, a262c2dc833f2fe1bd5c53a4d899e7077d3b1da9, b137af795399d8b657bad1646c18561530f35ed1)
Vendor Advisory: https://git.kernel.org/stable/c/0974d03eb479384466d828d65637814bee6b26d7
Restart Required: Yes
Instructions:
1. Update to a patched Linux kernel version from your distribution's repositories. 2. Reboot the system to load the new kernel. 3. Verify the kernel version after reboot.
🔧 Temporary Workarounds
Disable RTAS functionality
linuxRemove RTAS module or disable RTAS support in kernel configuration if not required.
echo 'blacklist rtas' > /etc/modprobe.d/rtas-blacklist.conf
update-initramfs -u
reboot
Apply kernel command line mitigations
linuxEnable Spectre v1 mitigations at kernel boot time.
Add 'spectre_v1=on' to kernel command line in bootloader configuration
🧯 If You Can't Patch
- Restrict local user access to systems, especially untrusted users.
- Implement strict privilege separation and limit user capabilities using SELinux/AppArmor.
🔍 How to Verify
Check if Vulnerable:
Check kernel version and architecture: uname -r and uname -m. If PowerPC architecture and running an unpatched kernel version, system is vulnerable.Check Version:
uname -rVerify Fix Applied:
Verify kernel version after update matches patched version from distribution. Check that array_index_nospec() is present in the sys_rtas() function.📡 Detection & Monitoring
Log Indicators:
- Unusual RTAS system call patterns
- Failed privilege escalation attempts
- Kernel oops or warnings related to RTAS
Network Indicators:
- Not applicable - local vulnerability
SIEM Query:
source="kernel" AND ("RTAS" OR "sys_rtas") AND ("error" OR "warning" OR "oops")🔗 References
- https://git.kernel.org/stable/c/0974d03eb479384466d828d65637814bee6b26d7
- https://git.kernel.org/stable/c/1f1feff02e9da0dd0cdb195c428c42b5f9b6c771
- https://git.kernel.org/stable/c/68d8156480940b79227d58865ec5d2947b9384a8
- https://git.kernel.org/stable/c/a262c2dc833f2fe1bd5c53a4d899e7077d3b1da9
- https://git.kernel.org/stable/c/b137af795399d8b657bad1646c18561530f35ed1
- https://git.kernel.org/stable/c/d2834ff1d9641a8695a09ea79cd901c7b6d4d05f
- https://lists.debian.org/debian-lts-announce/2025/05/msg00045.html
