CVE-2023-1582: Linux Kernel DoS Vulnerability

CVE-2023-1582 Overview

A race condition vulnerability was discovered in the Linux kernel's memory management subsystem, specifically within the fs/proc/task_mmu.c file. This vulnerability allows a local attacker with user privileges to exploit the race condition to cause a denial of service (DoS) on affected systems. The flaw exists in how the kernel handles concurrent memory operations, creating a window where improper synchronization can lead to system instability.

Critical Impact

Local attackers with user privileges can exploit this race condition to cause denial of service, potentially disrupting system availability on Linux servers and workstations.

Affected Products

• Linux Kernel versions 5.7-rc1 through 5.7-rc7
• Linux Kernel (various versions with vulnerable memory management code)
• Systems running affected Linux distributions with unpatched kernels

Discovery Timeline

• April 5, 2023 - CVE-2023-1582 published to NVD
• February 13, 2025 - Last updated in NVD database

Technical Details for CVE-2023-1582

Vulnerability Analysis

This vulnerability is classified as CWE-362 (Concurrent Execution using Shared Resource with Improper Synchronization), commonly known as a race condition. The flaw resides in the fs/proc/task_mmu.c file, which is responsible for providing memory mapping information through the /proc filesystem interface.

The race condition occurs when multiple threads or processes attempt to access memory management structures simultaneously without proper locking mechanisms. This type of vulnerability requires local access to exploit, meaning an attacker must have user-level access to the target system. The attack requires high complexity to successfully trigger the race window, but once exploited, it results in high availability impact, causing system instability or crashes.

Root Cause

The root cause of CVE-2023-1582 lies in insufficient synchronization primitives within the memory management code path. When the kernel processes requests for memory mapping information (typically accessed through /proc/[pid]/maps or related interfaces), there exists a time-of-check to time-of-use (TOCTOU) window where memory structures can change between validation and usage.

The vulnerable code path fails to properly hold locks while traversing memory regions, allowing concurrent modifications to occur. This improper synchronization can lead to accessing freed memory, corrupted data structures, or null pointer dereferences, ultimately resulting in a kernel panic or system hang.

Attack Vector

The attack vector for this vulnerability is local, requiring the attacker to have user-level access to the target system. The exploitation involves:

1. A local user creates multiple threads or processes that simultaneously access /proc filesystem entries related to memory management
2. The attacker triggers rapid, concurrent requests that exercise the vulnerable code path
3. By carefully timing these requests, the attacker attempts to hit the race window where memory structures are in an inconsistent state
4. Successful exploitation causes the kernel to access invalid memory regions, resulting in denial of service

While no verified exploit code is publicly available, the vulnerability mechanism involves concurrent access to process memory mapping interfaces. The Linux Kernel Memory Management Discussion thread provides additional technical context on the memory management components involved.

Detection Methods for CVE-2023-1582

Indicators of Compromise

• Unexpected kernel panics or system crashes with stack traces referencing fs/proc/task_mmu.c or related memory management functions
• Unusual patterns of /proc/[pid]/maps access from multiple threads simultaneously
• System logs showing memory corruption or null pointer dereference errors in memory management subsystem
• Processes repeatedly accessing proc filesystem memory interfaces in rapid succession

Detection Strategies

• Monitor kernel logs (dmesg) for crash reports or warnings related to task_mmu or memory management race conditions
• Deploy system monitoring to detect unusual process behavior accessing /proc filesystem entries at high frequency
• Use kernel debugging tools like lockdep to identify potential locking issues in development environments
• Implement audit rules to track access patterns to sensitive /proc filesystem entries

Monitoring Recommendations

• Enable kernel crash dump collection (kdump) to capture diagnostic information when crashes occur
• Configure syslog to forward kernel messages to a centralized logging system for analysis
• Monitor system stability metrics including uptime, kernel panic frequency, and memory subsystem errors
• Deploy endpoint detection solutions capable of identifying abnormal kernel behavior patterns

How to Mitigate CVE-2023-1582

Immediate Actions Required

• Update the Linux kernel to a patched version that addresses the race condition in fs/proc/task_mmu.c
• Apply security updates from your Linux distribution vendor as they become available
• Restrict local user access on critical systems to minimize the attack surface
• Monitor systems for signs of denial of service attempts targeting this vulnerability

Patch Information

Organizations should update their Linux kernel to a version that includes the fix for CVE-2023-1582. Check with your Linux distribution vendor for specific patched kernel versions. The fix involves implementing proper synchronization mechanisms to prevent the race condition when accessing memory mapping information.

For detailed technical discussion on the memory management components affected, refer to the Linux Kernel Memory Management Discussion on the kernel mailing list.

Workarounds

• Limit local user access to systems running vulnerable kernel versions to reduce the potential attack surface
• Implement process sandboxing or containerization to restrict access to /proc filesystem entries
• Monitor and rate-limit access to /proc/[pid]/maps and related memory mapping interfaces where feasible
• Consider deploying additional access controls on multi-user systems until patching is complete

# Check current kernel version for vulnerability assessment
uname -r

# View kernel security updates available from your distribution
# For Debian/Ubuntu:
apt list --upgradable | grep linux-image

# For RHEL/CentOS:
yum check-update kernel

# For Fedora:
dnf check-update kernel