CVE-2014-1943 in Mac OS X
Summary
by MITRE
Fine Free file before 5.17 allows context-dependent attackers to cause a denial of service (infinite recursion, CPU consumption, and crash) via a crafted indirect offset value in the magic of a file.
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Analysis
by VulDB Data Team • 02/03/2019
The vulnerability identified as CVE-2014-1943 affects the Fine Free file utility version 5.17 and earlier, representing a critical denial of service flaw that can be exploited through crafted file magic values. This vulnerability specifically targets the file type detection mechanism within the utility, where the software fails to properly validate indirect offset values during magic number processing. The flaw exists in the way the application parses and interprets file signatures, creating a condition where maliciously constructed indirect offset values can trigger recursive processing loops that consume excessive system resources.
The technical implementation of this vulnerability stems from inadequate input validation within the file magic parsing routine. When the file utility encounters a crafted file with manipulated magic numbers containing invalid indirect offset values, it attempts to resolve these offsets through recursive function calls without proper bounds checking or termination conditions. This recursive behavior leads to infinite recursion patterns that can exhaust available CPU cycles and memory resources, ultimately causing the application to crash or become unresponsive. The vulnerability operates at the application layer and requires no special privileges to exploit, making it particularly dangerous in environments where file processing utilities are frequently used.
From an operational perspective, this vulnerability presents significant risks to system availability and resource management. Attackers can craft malicious files that, when processed by the vulnerable file utility, will consume excessive computational resources and potentially bring down systems that rely on this utility for file type detection. The impact extends beyond simple denial of service as the infinite recursion can cause system instability and may affect other processes running on the same system. This type of vulnerability aligns with CWE-674, which describes "Uncontrolled Recursion" as a weakness that can lead to resource exhaustion and system instability. The vulnerability also maps to ATT&CK technique T1499.004, which covers "Utilities: File Deletion" and related resource consumption attacks that can be used to disrupt system availability.
Mitigation strategies for this vulnerability include immediate patching of the Fine Free file utility to version 5.17 or later, which contains the necessary fixes for proper offset validation. Organizations should implement input sanitization measures that validate all magic number offsets before processing and establish resource limits on file processing utilities to prevent excessive CPU consumption. Network administrators should also consider implementing file type validation at network boundaries to prevent malicious files from reaching systems that process them with vulnerable utilities. Additionally, monitoring systems should be configured to detect unusual CPU usage patterns that may indicate exploitation attempts, and regular security assessments should verify that all file processing utilities are properly updated and patched against known vulnerabilities. The fix typically involves implementing proper bounds checking and termination conditions for recursive offset resolution processes, ensuring that indirect offset values are validated against expected ranges before being processed.