CVE-2021-44577 in libsolv
Summary
by MITRE • 02/21/2022
Two heap-overflow vulnerabilities exist in openSUSE libsolv through 13 Dec 2020 bugs in the propagate function at src/solver.c: line 490 and 524.
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Analysis
by VulDB Data Team • 02/25/2022
The heap-overflow vulnerabilities identified in openSUSE libsolv represent critical security flaws that can lead to arbitrary code execution and system compromise. These issues affect versions of the libsolv library released through December 13, 2020, and stem from improper memory handling within the propagate function located in src/solver.c at lines 490 and 524. The vulnerabilities arise when the library processes package dependency resolution data, specifically during the propagation of package constraints and dependencies. The heap overflows occur due to insufficient bounds checking on memory allocations and buffer operations, allowing attackers to write beyond allocated memory regions. This flaw directly corresponds to CWE-121 Heap-based Buffer Overflow, which is classified under the Common Weakness Enumeration framework as a critical memory safety issue. The technical implementation involves the library's inability to properly validate input data during dependency resolution, particularly when handling complex package relationships and constraints that trigger the vulnerable code paths.
The operational impact of these vulnerabilities extends beyond simple memory corruption, as they provide attackers with potential pathways for privilege escalation and system compromise. When exploited, the heap overflows can result in denial of service conditions, data corruption, or more severe arbitrary code execution depending on the attack vector and system configuration. The vulnerabilities are particularly concerning because libsolv is widely used as a package management dependency resolver across various linux distributions, including openSUSE and others that incorporate this library. Attackers could leverage these flaws by crafting malicious package metadata or dependency chains that trigger the vulnerable code paths during normal package installation or update operations. The attack surface is broad given that many package management systems rely on libsolv for dependency resolution, making the impact of exploitation widespread across affected systems. From an adversarial perspective, this vulnerability aligns with ATT&CK technique T1059.007 for Command and Scripting Interpreter, where attackers might use the heap overflow to execute arbitrary code within the context of the package manager process.
Mitigation strategies for CVE-2021-44577 should prioritize immediate patching of affected libsolv versions to the latest stable releases that contain the memory safety fixes. System administrators should implement comprehensive monitoring for unusual package management activities and dependency resolution patterns that might indicate exploitation attempts. The recommended approach includes deploying automated patch management systems to ensure all affected systems receive updates promptly. Additionally, organizations should consider implementing network segmentation and access controls to limit potential attack vectors targeting package management systems. Security teams should conduct vulnerability assessments to identify all systems running vulnerable versions of libsolv and prioritize remediation efforts accordingly. The fix typically involves implementing proper bounds checking, memory validation, and input sanitization within the propagate function to prevent buffer overflows. Organizations should also establish incident response procedures specifically addressing potential exploitation of heap-based vulnerabilities in package management tools, as these flaws can provide persistent access to compromised systems. Regular security auditing of dependency management systems and maintaining up-to-date threat intelligence on similar vulnerabilities in related software components will further strengthen defensive measures against such attacks.