CVE-2022-39377: Sysstat Project Sysstat RCE Vulnerability

CVE-2022-39377 Overview

CVE-2022-39377 is an integer overflow vulnerability affecting sysstat, a widely-used set of system performance monitoring tools for the Linux operating system. On 32-bit systems running sysstat versions 9.1.16 through 12.7.0, the allocate_structures function in sa_common.c contains a size_t overflow that can lead to Remote Code Execution (RCE).

The vulnerability stems from insufficient bounds checking before arithmetic multiplication operations, allowing an attacker to trigger an overflow in the size allocated for the buffer representing system activities. This buffer overflow can then be exploited to execute arbitrary code on the affected system.

Critical Impact

This integer overflow vulnerability in sysstat can allow attackers to achieve Remote Code Execution on vulnerable 32-bit Linux systems, potentially leading to full system compromise.

Affected Products

• sysstat versions 9.1.16 to 12.7.0
• Debian Linux 10.0
• Fedora 35, 36, and 37

Discovery Timeline

• 2022-11-08 - CVE-2022-39377 published to NVD
• 2025-11-03 - Last updated in NVD database

Technical Details for CVE-2022-39377

Vulnerability Analysis

The vulnerability resides in the allocate_structures function within sa_common.c. This function is responsible for allocating memory buffers used to store system activity data collected by sysstat utilities. On 32-bit systems, the function performs arithmetic multiplication to calculate the required buffer size without adequate bounds checking.

When processing specially crafted input, an attacker can cause the multiplication operation to overflow, resulting in a much smaller memory allocation than intended. Subsequent operations that write data into this undersized buffer will overflow its boundaries, corrupting adjacent memory regions.

The CWE classifications for this vulnerability include CWE-120 (Buffer Copy without Checking Size of Input) and CWE-131 (Incorrect Calculation of Buffer Size), which accurately describe the root cause and manifestation of this security flaw.

Root Cause

The root cause is an insufficient bounds check in the allocate_structures function before performing arithmetic multiplication to determine buffer sizes. On 32-bit architectures, size_t is typically 32 bits, making it susceptible to overflow when multiplying large values. The function fails to validate that the product of the multiplication will fit within the size_t data type, leading to integer overflow and subsequent buffer overflow conditions.

Attack Vector

The attack requires local access to the system with the ability to provide malicious input to sysstat utilities. An attacker must craft input that causes the size calculation to overflow, resulting in a small memory allocation. The attacker then exploits the subsequent buffer overflow to overwrite critical memory structures, potentially achieving code execution.

The exploitation scenario involves:

1. Crafting input with values designed to cause integer overflow during buffer size calculation
2. Triggering the vulnerable code path in allocate_structures
3. Exploiting the resulting heap buffer overflow to corrupt memory
4. Gaining control of program execution flow to execute arbitrary code

Due to the local attack vector and the requirement for user interaction, exploitation requires either social engineering to trick a user into processing malicious data or access to a multi-user system where the attacker can target other users' sysstat processes.

Detection Methods for CVE-2022-39377

Indicators of Compromise

• Unexpected crashes or segmentation faults in sysstat utilities (sar, sadc, iostat)
• Anomalous memory allocation patterns in sysstat processes on 32-bit systems
• Unusual process behavior following sysstat utility execution
• Core dumps generated by sysstat components indicating heap corruption

Detection Strategies

• Monitor system logs for sysstat process crashes or abnormal terminations
• Implement file integrity monitoring on sysstat binary files and configuration
• Use application-level monitoring to detect memory corruption attempts
• Deploy endpoint detection solutions capable of identifying heap overflow exploitation techniques

Monitoring Recommendations

• Enable core dump analysis for sysstat processes to identify exploitation attempts
• Monitor for unusual process spawning or network connections following sysstat execution
• Implement audit logging for sysstat utility invocations on critical systems
• Review system logs for patterns indicative of exploitation attempts targeting this vulnerability

How to Mitigate CVE-2022-39377

Immediate Actions Required

• Upgrade sysstat to version 12.7.1 or later immediately on all affected systems
• Prioritize 32-bit Linux systems as they are directly vulnerable to this issue
• Apply distribution-specific security updates from Debian, Fedora, or Gentoo repositories
• Restrict access to sysstat utilities to trusted users only until patching is complete

Patch Information

The vulnerability has been patched in sysstat version 12.7.1. System administrators should update to this version or apply distribution-specific security patches. Multiple Linux distributions have released security advisories and patches:

• Debian: Security updates available via Debian LTS Announcement
• Fedora: Patches available for Fedora 35, 36, and 37 via Fedora Package Announcements
• Gentoo: Security advisory GLSA 202211-07 provides patch details

For complete technical details, refer to the GitHub Security Advisory.

Workarounds

• Restrict execution permissions for sysstat utilities to root or trusted administrators only
• Consider temporarily disabling or removing sysstat on 32-bit systems until patches can be applied
• Implement strict input validation at the system level for any data processed by sysstat
• Use containerization or sandboxing to isolate sysstat processes from critical system components

# Check installed sysstat version
sar -V

# Update sysstat on Debian/Ubuntu systems
sudo apt update && sudo apt upgrade sysstat

# Update sysstat on Fedora systems
sudo dnf update sysstat

# Update sysstat on Gentoo systems
sudo emerge --sync && sudo emerge -av app-admin/sysstat