CVE-2014-8117 in file
Summary
by MITRE
softmagic.c in file before 5.21 does not properly limit recursion, which allows remote attackers to cause a denial of service (CPU consumption or crash) via unspecified vectors.
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Analysis
by VulDB Data Team • 03/01/2022
The vulnerability identified as CVE-2014-8117 resides within the file command utility's softmagic.c component in versions prior to 5.21. This flaw represents a classic recursion limitation issue that can be exploited to perform denial of service attacks against systems relying on the file command for MIME type detection and file identification. The vulnerability specifically affects the magic file parsing mechanism that the file command uses to determine file types based on their content patterns. When processing specially crafted magic files or input data, the recursive parsing logic fails to enforce proper depth limits, creating a potential for unbounded recursion that can exhaust system resources.
The technical implementation of this vulnerability stems from inadequate recursion depth checking within the magic file parsing engine. The softmagic.c module handles the interpretation of magic number patterns that define how the file command identifies different file types. When encountering complex or maliciously constructed magic files, the parser can enter infinite recursive loops without proper bounds checking. This behavior manifests as either excessive cpu consumption as the system processes recursive calls or complete application crashes when stack overflow occurs. The vulnerability is particularly dangerous because the file command is widely used across various systems for automated file type detection, making it a prime target for resource exhaustion attacks.
From an operational perspective, this vulnerability poses significant risks to systems that rely on the file command for automated file processing, including web servers, mail servers, and content management systems. Attackers can craft malicious input files or magic patterns that trigger the recursive behavior, leading to sustained cpu spikes that can degrade system performance or cause complete service outages. The impact extends beyond simple denial of service as the vulnerability can be leveraged in distributed denial of service attacks where multiple systems are simultaneously targeted. According to the CWE classification system, this vulnerability maps to CWE-674, which specifically addresses uncontrolled recursion in software components. The attack surface is broad since many applications depend on the file command for file validation and type detection, making this a critical vulnerability for system administrators to address.
The mitigation strategy involves upgrading to file command version 5.21 or later, which implements proper recursion depth limiting mechanisms. Organizations should also implement input validation measures to prevent processing of untrusted magic files, particularly in environments where the file command is used in automated processing pipelines. Network segmentation and monitoring can help detect unusual cpu usage patterns that might indicate exploitation attempts. From an ATT&CK framework perspective, this vulnerability aligns with techniques involving resource exhaustion and service disruption, specifically mapping to tactics related to denial of service and privilege escalation through system instability. Regular patch management processes should include verification that the file command is updated to versions that address this recursion limitation issue, as the vulnerability can be exploited without authentication and requires minimal technical expertise to implement successfully.