CVE-2017-16869 in UPX
Summary
by MITRE
** DISPUTED ** p_mach.cpp in UPX 3.94 allows remote attackers to cause a denial of service (invalid memory access and application crash) or possibly have unspecified other impact via a crafted Mach-O file, related to canPack and unpack functions. NOTE: the vendor has stated "there is no security implication whatsoever."
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Analysis
by VulDB Data Team • 08/06/2024
The vulnerability identified as CVE-2017-16869 resides within the p_mach.cpp component of UPX version 3.94, a widely used open-source executable packer and unpacker. This flaw manifests in the handling of Mach-O binary formats specifically when processing files through the canPack and unpack functions. The issue represents a potential remote code execution vector that could be exploited by malicious actors to trigger invalid memory access conditions leading to application crashes and denial of service scenarios.
The technical implementation of this vulnerability stems from inadequate input validation within the Mach-O file parsing logic. When UPX encounters a specially crafted Mach-O file, the canPack and unpack functions fail to properly validate the structure and content of the binary headers, resulting in memory access violations. This type of vulnerability falls under the CWE-125 weakness category, which describes out-of-bounds read conditions that can lead to memory corruption and system instability. The flaw demonstrates characteristics of improper input validation and memory management errors that are commonly exploited in binary exploitation scenarios.
From an operational perspective, this vulnerability creates significant risk for systems that rely on UPX for executable compression and distribution. Attackers could potentially craft malicious Mach-O files designed to crash UPX processes during unpacking operations, effectively disrupting legitimate software deployment workflows. The denial of service impact extends beyond simple application crashes, as the invalid memory access conditions could potentially be leveraged to execute arbitrary code under certain circumstances, though the vendor has disputed the security implications. The vulnerability affects systems running macOS and other platforms that utilize Mach-O binary formats, making it particularly relevant for enterprise environments that distribute software through compressed executables.
The security community has expressed mixed views on the actual threat level presented by this vulnerability, with the vendor explicitly stating there are "no security implications whatsoever." However, the potential for unspecified other impacts cannot be entirely dismissed, particularly in environments where UPX is used as part of automated build and deployment pipelines. Organizations should consider implementing additional validation measures and monitoring for unusual UPX behavior when processing external binary files. The ATT&CK framework categorizes this type of vulnerability under the T1059.007 technique for "Command and Scripting Interpreter: JavaScript' where the exploitation could potentially lead to privilege escalation or system compromise through indirect attack vectors.
Mitigation strategies should focus on implementing proper input validation controls and restricting the execution of untrusted binary files through UPX. Organizations should consider updating to newer versions of UPX where such vulnerabilities have been addressed, while also implementing network segmentation and access controls to limit exposure. Additionally, regular security assessments should include testing for similar vulnerabilities in other binary processing tools, as this represents a common attack surface in software supply chain security. The vulnerability underscores the importance of maintaining up-to-date software components and implementing comprehensive security controls around executable processing and distribution systems.