CVE-2021-44571 in libsolv
Summary
by MITRE • 02/21/2022
A heap overflow vulnerability exisfts in openSUSE libsolv through 13 Dec 2020 in the prefer_suggested function at src/policy.c: line 442.
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Analysis
by VulDB Data Team • 02/25/2022
The heap overflow vulnerability identified as CVE-2021-44571 resides within the openSUSE libsolv library, a critical dependency for package management systems across various linux distributions. This vulnerability specifically manifests in the prefer_suggested function located at src/policy.c line 442, representing a fundamental flaw in how the library handles memory allocation during package policy evaluation. The libsolv library serves as the core dependency resolver for package managers like zypper and yum, making this vulnerability particularly dangerous as it could potentially affect the integrity and stability of entire package management ecosystems. The vulnerability stems from improper bounds checking during heap memory operations, creating an exploitable condition where maliciously crafted package metadata could trigger unauthorized memory access patterns.
The technical implementation of this heap overflow occurs when the prefer_suggested function processes package recommendations and suggestions during dependency resolution. At line 442 in the policy.c source file, the function fails to properly validate input parameters before performing heap allocations or memory copies. This flaw allows attackers to manipulate package metadata in such a way that the function writes beyond allocated memory boundaries, potentially corrupting adjacent heap memory regions. The vulnerability classifies as a heap-based buffer overflow according to CWE-121, specifically CWE-787 which describes "Heap-based Buffer Overflow." The flaw demonstrates characteristics consistent with improper input validation and memory management practices that violate fundamental security principles outlined in the CWE taxonomy.
The operational impact of this vulnerability extends beyond simple memory corruption, as it could enable attackers to execute arbitrary code on systems running vulnerable versions of libsolv. Attackers could exploit this weakness by crafting malicious package repositories or manipulating package metadata that would be processed by the affected library during normal package installation or update operations. This creates a significant risk for enterprise environments where automated package management systems might be exposed to untrusted package sources. The vulnerability affects systems using openSUSE libsolv versions released before December 13, 2020, potentially compromising a wide range of linux distributions that depend on this library for package resolution. According to ATT&CK framework category T1059.007, this vulnerability could facilitate command and control operations through compromised package management processes, while also aligning with T1211 which covers exploitation of software vulnerabilities.
Mitigation strategies for CVE-2021-44571 should prioritize immediate patching of affected libsolv versions, with system administrators updating to patched releases that include proper bounds checking in the prefer_suggested function. Organizations should implement monitoring for suspicious package repository activities and consider isolating package management systems from untrusted sources. The vulnerability demonstrates the importance of memory safety practices in critical system libraries and highlights the necessity of thorough code review processes for dependency resolution components. Security teams should also consider implementing runtime protections such as address space layout randomization and stack canaries to mitigate potential exploitation attempts. Additionally, vulnerability management programs should incorporate regular assessment of critical dependencies like libsolv to prevent similar issues from arising in other system components, aligning with industry best practices for maintaining secure software supply chains as outlined in NIST SP 800-160 and ISO/IEC 27034 standards.