CVE-2021-44576 in libsolv
Summary
by MITRE • 02/21/2022
Two memory vulnerabilities exists in openSUSE libsolv through 13 Dec 2020 in the resolve_weak function at src/solver.c: line 2222 and 2249.
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Analysis
by VulDB Data Team • 02/25/2022
The vulnerability CVE-2021-44576 represents a critical memory handling issue within the openSUSE libsolv library, a fundamental component used for dependency resolution in package management systems. This library serves as the backbone for various Linux distributions including openSUSE, SUSE Linux Enterprise, and others that rely on sophisticated package dependency solving algorithms. The flaw manifests within the resolve_weak function located in the src/solver.c file at lines 2222 and 2249, where improper memory management practices create exploitable conditions that could lead to system compromise.
The technical nature of this vulnerability stems from inadequate memory allocation and deallocation mechanisms within the resolve_weak function, which is responsible for handling weak dependencies during package resolution processes. When the solver encounters certain dependency scenarios, particularly those involving complex package relationships and weak dependencies, the function fails to properly manage memory resources, leading to potential memory corruption conditions. This memory management failure creates opportunities for attackers to craft malicious package dependencies that could trigger buffer overflows, use-after-free conditions, or other memory corruption vulnerabilities that could be exploited to execute arbitrary code or cause denial of service conditions.
The operational impact of this vulnerability extends beyond simple denial of service scenarios, as it affects the core package management functionality that underpins system stability and security. Attackers could potentially exploit this vulnerability through package repositories, package installation processes, or even through compromised package sources, making it particularly dangerous in environments where automated package updates occur. The vulnerability affects systems that rely on libsolv for dependency resolution, including enterprise Linux distributions, containerized environments, and any system where package management integrity is critical for maintaining system security posture. Given that libsolv is widely deployed across multiple Linux distributions, the potential attack surface is substantial, with the vulnerability potentially affecting thousands of systems in production environments.
Mitigation strategies for CVE-2021-44576 should prioritize immediate patching of affected libsolv versions, with particular attention to updating to versions released after December 13, 2020, when the vulnerability was addressed. System administrators should implement comprehensive monitoring of package management activities and consider implementing additional security controls such as package integrity verification, repository validation, and restricted package installation policies. The vulnerability aligns with CWE-125, which addresses out-of-bounds read conditions, and CWE-416, which covers use-after-free errors, both of which are commonly exploited in package management and dependency resolution contexts. From an ATT&CK framework perspective, this vulnerability could be leveraged in initial access phases through supply chain attacks targeting package repositories or in privilege escalation scenarios where compromised package management processes could be used to gain elevated system privileges. Organizations should also consider implementing network segmentation controls around package management systems and establishing robust incident response procedures for detecting and responding to potential exploitation attempts targeting package management infrastructure.