CVE-2017-8847 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 (NULL pointer dereference and application crash) via a crafted archive.
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Analysis
by VulDB Data Team • 12/06/2022
The vulnerability identified as CVE-2017-8847 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 within the liblrzip.so shared library. The flaw manifests when the application processes malformed or crafted archive files, leading to a NULL pointer dereference that ultimately causes the application to crash and terminate unexpectedly. This vulnerability demonstrates a classic buffer handling error where the software fails to properly validate input data before attempting to access memory locations, creating an exploitable condition that can be leveraged by remote attackers to disrupt service availability.
The technical implementation of this vulnerability stems from inadequate input validation within the decompression logic of lrzip's archive processing pipeline. When a maliciously crafted archive is presented to the system, the bufRead::get() function attempts to read from a buffer that has not been properly initialized or validated, resulting in a NULL pointer dereference. This condition falls under CWE-476 which specifically addresses NULL pointer dereference vulnerabilities, where an application attempts to access memory through a pointer that has not been properly initialized or has been set to NULL. The flaw represents a failure in defensive programming practices and demonstrates the importance of proper input sanitization and validation in security-critical applications.
From an operational perspective, this vulnerability poses significant risks to systems that rely on lrzip for archive management and data compression tasks. Remote attackers can exploit this weakness to perform denial of service attacks against systems processing compressed data, potentially disrupting legitimate operations and causing service unavailability. The impact extends beyond simple application crashes as it can affect automated systems, backup processes, and any service that depends on reliable archive handling. This vulnerability aligns with ATT&CK technique T1499.004 which covers network denial of service attacks, where adversaries leverage application-level flaws to disrupt services and compromise availability. The exploitability of this issue means that any system processing untrusted archive files could be vulnerable to remote compromise, making it particularly dangerous in environments where archive files are processed automatically or from external sources.
The mitigation strategies for CVE-2017-8847 primarily focus on updating to patched versions of lrzip where the input validation has been strengthened and proper null pointer checks have been implemented. System administrators should prioritize applying security updates to eliminate this vulnerability from their environments. Additionally, implementing proper input validation at the application level and employing sandboxing techniques when processing untrusted archive files can provide additional defense in depth. Organizations should also consider implementing network segmentation and access controls to limit exposure to potentially malicious archive files. The vulnerability underscores the importance of regular security assessments and patch management programs, as it demonstrates how seemingly minor input validation flaws can result in significant security implications. Proper logging and monitoring of archive processing activities can also help detect exploitation attempts and provide early warning of potential attacks targeting this specific vulnerability.