CVE-2017-5981 in ZZIPlib
Summary
by MITRE
seeko.c in zziplib 0.13.62 allows remote attackers to cause a denial of service (assertion failure and crash) via a crafted ZIP file.
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Analysis
by VulDB Data Team • 07/10/2025
The vulnerability identified as CVE-2017-5981 affects zziplib version 0.13.62 and specifically targets the seeko.c component within this library. This issue represents a denial of service vulnerability that can be exploited by remote attackers through the manipulation of ZIP file archives. The flaw manifests as an assertion failure that ultimately leads to a system crash, effectively disrupting normal operations and potentially allowing attackers to cause service interruptions. The vulnerability stems from inadequate input validation within the zziplib library's handling of compressed archive files, particularly when processing malformed or specially crafted ZIP archives that contain unexpected data structures or sequences.
The technical implementation of this vulnerability involves the seeko.c module failing to properly validate file offsets and positioning data during ZIP file parsing operations. When a maliciously crafted ZIP file is processed, the library's internal assertion mechanisms detect what it perceives as an invalid state or inconsistent data structure, triggering an assertion failure that terminates the application process. This behavior aligns with CWE-617, which describes reachable assertions that can be triggered by external inputs, and represents a classic example of an unchecked input validation error in archive processing libraries. The vulnerability demonstrates how improper error handling in decompression routines can be leveraged to create denial of service conditions without requiring elevated privileges or complex exploitation techniques.
From an operational impact perspective, this vulnerability poses significant risks to systems that rely on zziplib for processing untrusted ZIP archives. Applications using this library may experience unexpected crashes when handling maliciously constructed files, potentially leading to complete service disruption. The vulnerability affects any system where zziplib is integrated into file processing workflows, including web applications, file servers, and content management systems that accept user-uploaded ZIP files. Attackers can exploit this weakness by simply providing a crafted ZIP file that triggers the assertion failure, making the attack vector relatively simple and accessible. The impact extends beyond immediate service disruption as system administrators must respond to crashes, potentially leading to extended downtime and resource allocation for incident response activities.
Mitigation strategies for CVE-2017-5981 should prioritize immediate patching of affected zziplib installations to version 0.13.63 or later, which contains the necessary fixes for the assertion failure issue. Organizations should implement comprehensive input validation measures for all ZIP file processing operations, including preliminary file format checks and size limitations to prevent exploitation attempts. Network-level defenses such as content filtering systems and web application firewalls can provide additional protection by scanning for suspicious file patterns before they reach vulnerable applications. Security monitoring should be enhanced to detect unusual crash patterns or service disruptions that may indicate exploitation attempts. The vulnerability also highlights the importance of maintaining up-to-date third-party libraries and implementing robust dependency management practices. This case exemplifies ATT&CK technique T1499.004, which involves the use of denial of service attacks against applications, and underscores the necessity of proper error handling and input validation in security-critical software components. Organizations should conduct thorough vulnerability assessments of their software dependencies to identify similar issues in other libraries that may present comparable risks.