CVE-2017-8842 in lrzip
Summary
by MITRE
The bufRead::get() function in libzpaq/libzpaq.h in liblrzip.so in lrzip 0.631 allows remote attackers to cause a denial of service (divide-by-zero error and application crash) via a crafted archive.
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Analysis
by VulDB Data Team • 08/25/2025
The vulnerability identified as CVE-2017-8842 represents a critical denial of service flaw within the lrzip compression utility version 0.631. This issue specifically affects the bufRead::get() function located in the libzpaq/libzpaq.h header file of the liblrzip.so shared library. The flaw manifests when processing maliciously crafted archive files, creating a scenario where remote attackers can deliberately trigger system instability through carefully constructed input data. The vulnerability operates at the core of the decompression process where the application fails to properly validate input parameters before performing arithmetic operations.
The technical implementation of this vulnerability stems from a divide-by-zero error condition that occurs within the bufRead::get() function when handling malformed archive data. When the application encounters a specially crafted archive, the function attempts to perform a division operation using a zero value as the divisor, which fundamentally violates mathematical principles and causes the application to crash immediately. This type of error falls under the common weakness enumeration CWE-369, which specifically addresses the division by zero vulnerability pattern. The flaw exists because the input validation mechanisms fail to properly sanitize or verify the integrity of archive metadata before processing, allowing malicious data to propagate through the system's decompression pipeline.
The operational impact of this vulnerability extends beyond simple application instability, as it enables remote attackers to execute denial of service attacks against systems running lrzip 0.631. Since the vulnerability can be triggered remotely through crafted archive files, attackers can potentially disrupt services that rely on lrzip for data compression and decompression operations. This creates a significant risk for systems that process untrusted archive files, including web applications, file sharing services, and automated processing pipelines. The crash condition results in complete application termination, which can lead to service disruption, data loss, and potential availability issues for legitimate users who depend on the affected systems.
Mitigation strategies for CVE-2017-8842 should prioritize immediate software updates to versions that address the divide-by-zero condition in the bufRead::get() function. System administrators should implement input validation measures that filter or reject suspicious archive files before they reach the decompression stage, leveraging signature-based detection or heuristic analysis to identify potentially malicious content. The implementation of proper error handling and input sanitization within the affected library components can prevent the propagation of malformed data through the system. Additionally, network segmentation and access controls should be enforced to limit exposure to untrusted archive sources, while monitoring systems should be deployed to detect unusual patterns of archive processing that might indicate exploitation attempts. Organizations should also consider implementing sandboxing techniques for archive processing to contain potential impacts and ensure that the vulnerability cannot be leveraged for more sophisticated attacks beyond simple denial of service.