CVE-2021-37600 in util-linux
Summary
by MITRE • 07/30/2021
An integer overflow in util-linux through 2.37.1 can potentially cause a buffer overflow if an attacker were able to use system resources in a way that leads to a large number in the /proc/sysvipc/sem file.
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Analysis
by VulDB Data Team • 08/04/2024
The vulnerability identified as CVE-2021-37600 represents a critical integer overflow condition within the util-linux package version 2.37.1 and earlier. This flaw exists in the handling of system resource management within the /proc/sysvipc/sem file which tracks semaphore information for inter-process communication. The integer overflow occurs when the system processes semaphore values that exceed the maximum representable value for the integer type used in the implementation, creating a potential pathway for buffer overflow conditions. The vulnerability is particularly concerning because it operates within the kernel's system VIPC (Virtual Inter-Process Communication) subsystem where semaphore management is critical for process coordination and system stability.
The technical implementation of this vulnerability stems from improper input validation and arithmetic handling within the util-linux utility that manages system semaphore resources. When the system encounters semaphore values that trigger integer overflow conditions, the subsequent buffer operations become unpredictable and potentially exploitable. The specific context involves the /proc/sysvipc/sem file which provides a virtual file interface to semaphore information, allowing processes to query and modify semaphore settings. The integer overflow manifests when large semaphore values are processed, causing the arithmetic operations to wrap around and produce unexpected results that can exceed buffer boundaries. This flaw aligns with CWE-190 which specifically addresses integer overflow conditions and their potential for cascading security issues.
The operational impact of this vulnerability extends beyond simple buffer overflow scenarios to potentially enable privilege escalation and system compromise. An attacker who can manipulate the semaphore values in /proc/sysvipc/sem file could theoretically trigger the integer overflow condition and subsequently exploit the resulting buffer overflow to execute arbitrary code with elevated privileges. The attack vector requires the ability to modify system resources in a controlled manner, potentially through process manipulation or resource exhaustion techniques that force the system into the overflow state. This vulnerability affects systems running util-linux versions up to 2.37.1 and represents a significant risk to system integrity, particularly in environments where multiple processes interact through semaphore-based communication mechanisms. The potential for exploitation aligns with ATT&CK technique T1068 which covers local privilege escalation through system-level vulnerabilities.
Mitigation strategies for CVE-2021-37600 focus primarily on updating to patched versions of util-linux where the integer overflow handling has been corrected. System administrators should immediately upgrade to util-linux version 2.37.2 or later where the vulnerability has been addressed through proper integer bounds checking and overflow prevention mechanisms. Additionally, monitoring systems should be implemented to detect unusual semaphore value changes in the /proc/sysvipc/sem file which could indicate attempted exploitation. Network segmentation and access controls should be strengthened to limit potential attackers' ability to manipulate system resources. The fix typically involves implementing proper input validation, using larger integer types where necessary, and ensuring that arithmetic operations are checked for overflow conditions before buffer operations occur. Organizations should also conduct vulnerability assessments to identify systems running vulnerable versions of util-linux and prioritize patching based on risk exposure and system criticality.