CVE-2021-34403
📋 TL;DR
This vulnerability in NVIDIA's nvmap ioctl driver allows local users to exploit a use-after-free condition, potentially gaining elevated privileges, accessing sensitive data, or causing system crashes. It affects systems running NVIDIA Linux distributions with vulnerable driver versions.
💻 Affected Systems
- NVIDIA Linux GPU Driver
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Local attacker gains root privileges, compromising the entire system's confidentiality, integrity, and availability.
Likely Case
Local user escalates privileges to gain unauthorized access to system resources or sensitive data.
If Mitigated
Attack contained to user-level impact if proper privilege separation and monitoring are in place.
🎯 Exploit Status
Exploitation requires local user access and knowledge of the vulnerability. The use-after-free condition in nvmap ioctl can be triggered to achieve privilege escalation.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 470.42.01 and later
Vendor Advisory: https://nvidia.custhelp.com/app/answers/detail/a_id/5259
Restart Required: Yes
Instructions:
1. Check current driver version. 2. Download and install NVIDIA driver version 470.42.01 or newer from NVIDIA's official website. 3. Reboot the system to apply changes.
🔧 Temporary Workarounds
Restrict local user access
linuxLimit the number of local user accounts and implement strict access controls to reduce attack surface.
Disable unnecessary NVIDIA services
linuxIf NVIDIA GPU functionality is not required, disable related services to reduce exposure.
sudo systemctl stop nvidia-persistenced
sudo systemctl disable nvidia-persistenced
🧯 If You Can't Patch
- Implement strict user access controls and monitor for suspicious local privilege escalation attempts.
- Isolate affected systems from critical network segments and implement additional security monitoring.
🔍 How to Verify
Check if Vulnerable:
Check NVIDIA driver version with 'nvidia-smi' or 'cat /proc/driver/nvidia/version' and compare against vulnerable versions.Check Version:
nvidia-smi | grep 'Driver Version'Verify Fix Applied:
Verify driver version is 470.42.01 or newer using 'nvidia-smi' command.📡 Detection & Monitoring
Log Indicators:
- Unusual privilege escalation attempts
- Kernel crash logs related to nvmap
- Failed authentication attempts followed by successful privilege changes
Network Indicators:
- Not applicable - local exploit only
SIEM Query:
source="kernel" AND "nvmap" AND ("use-after-free" OR "privilege escalation")