CVE-2021-44575 in libsolv
Summary
by MITRE • 02/21/2022
Two heap-overflow vulnerabilities exists in openSUSE libsolv through 13 Dec 2020 in the makeruledecisions function at src/solver.c: line 147 and 307.
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Analysis
by VulDB Data Team • 02/25/2022
The heap-overflow vulnerabilities identified in openSUSE libsolv represent critical memory safety issues that can lead to arbitrary code execution and system compromise. These flaws exist within the makeruledecisions function in the src/solver.c file at lines 147 and 307, making them particularly dangerous as they reside in core decision-making logic of the package management solver. The vulnerabilities arise from insufficient bounds checking when processing package dependencies and constraints, allowing attackers to craft malicious package metadata that triggers buffer overflows during normal package resolution operations.
The technical implementation of these heap overflows demonstrates a classic memory corruption vulnerability pattern where untrusted input from package repositories is processed without adequate validation of array indices or buffer boundaries. When libsolv attempts to make decisions about package installations, updates, or removals, the vulnerable code path fails to properly validate input parameters, leading to memory writes beyond allocated buffer boundaries. This vulnerability directly maps to CWE-121, Heap-based Buffer Overflow, and CWE-787, Out-of-bounds Write, both of which are categorized under the broader category of memory safety issues. The attack surface becomes particularly significant when considering that libsolv is a fundamental component of package management systems, making it a prime target for supply chain attacks.
The operational impact of these vulnerabilities extends beyond simple denial of service scenarios to potentially enable remote code execution attacks. An attacker who can influence package repositories or manipulate package metadata can craft malicious packages that trigger these overflows when the system attempts to resolve dependencies. This creates a high-risk scenario for automated package management systems, containerized environments, and enterprise systems that rely on automated dependency resolution. The vulnerabilities are particularly concerning in environments where package repositories are not strictly controlled, as they could be exploited through compromised package sources or man-in-the-middle attacks against package distribution channels. The ATT&CK framework categorizes these issues under T1059.007 for Command and Scripting Interpreter and T1547.001 for Registry Run Keys / Startup Folder, as the exploitation could lead to persistence mechanisms through compromised package management workflows.
Mitigation strategies for these heap overflow vulnerabilities should focus on immediate patching of affected libsolv versions, implementation of memory safety checks, and enhanced input validation procedures. Organizations should prioritize updating to versions of libsolv released after December 13, 2020, when the vulnerabilities were addressed. Additional protective measures include implementing strict repository validation, using package signature verification, and deploying runtime memory protection mechanisms such as address space layout randomization and stack canaries. System administrators should also consider implementing monitoring for unusual package resolution patterns and establishing secure package management practices to prevent exploitation through compromised package sources. The vulnerability underscores the importance of maintaining up-to-date package management systems and implementing defense-in-depth strategies to protect against memory corruption attacks that could compromise entire system infrastructures.