CVE-2020-11937 in whoopsie
Summary
by MITRE
In whoopsie, parse_report() from whoopsie.c allows a local attacker to cause a denial of service via a crafted file. The DoS is caused by resource exhaustion due to a memory leak. Fixed in 0.2.52.5ubuntu0.5, 0.2.62ubuntu0.5 and 0.2.69ubuntu0.1.
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Analysis
by VulDB Data Team • 11/07/2020
The vulnerability identified as CVE-2020-11937 affects the whoopsie component, which is responsible for handling crash reports in Ubuntu systems. This local privilege escalation vulnerability stems from a flaw in the parse_report() function within whoopsie.c, where the application fails to properly handle malformed input files. The issue manifests when a local attacker crafts a specially designed file that triggers improper memory management during the parsing process, leading to resource exhaustion and ultimately causing a denial of service condition. The vulnerability represents a classic memory leak scenario where allocated memory is not properly freed, gradually consuming system resources until the affected service becomes unresponsive.
The technical implementation of this vulnerability resides in the input validation and memory management practices within the whoopsie daemon. When the parse_report() function processes a crafted file, it fails to properly validate the structure and content of the input, causing the application to allocate memory without subsequent deallocation. This memory leak accumulates over time and can be exploited by an attacker to exhaust available memory resources, effectively preventing the whoopsie service from functioning properly and potentially impacting system stability. The vulnerability is classified as a local privilege escalation vector since exploitation requires local system access but does not require elevated privileges to initiate the attack. This flaw aligns with CWE-401, which specifically addresses improper handling of memory allocation and deallocation in software systems.
The operational impact of this vulnerability extends beyond simple service disruption, as the whoopsie daemon plays a critical role in system crash reporting and error handling within Ubuntu environments. When compromised, the daemon's denial of service condition can prevent proper crash reporting, making system troubleshooting more difficult for administrators. The vulnerability affects multiple Ubuntu releases and versions, with specific fixed versions including 0.2.52.5ubuntu0.5, 0.2.62ubuntu.5, and 0.2.69ubuntu.1, indicating the widespread nature of the issue across different system configurations. Attackers can leverage this vulnerability to degrade system performance or availability, potentially disrupting critical services that depend on proper crash reporting mechanisms. The memory exhaustion effect can also impact other system processes that rely on available memory resources.
Mitigation strategies for this vulnerability should focus on applying the vendor-provided patches and updates immediately upon availability. System administrators should prioritize patch management to ensure all affected Ubuntu systems receive the necessary updates that address the memory leak in the parse_report() function. Additionally, implementing monitoring solutions that track memory usage patterns and unusual resource consumption can help detect exploitation attempts before they cause significant disruption. Network segmentation and access controls should be maintained to limit local access to systems where whoopsie operates, reducing the attack surface for potential exploitation. The fix implemented by Ubuntu developers addresses the root cause by properly managing memory allocation and deallocation within the parsing routine, ensuring that all allocated resources are appropriately freed regardless of input validation outcomes. This remediation approach follows established security practices for preventing memory-related vulnerabilities and aligns with defensive coding principles recommended in various security frameworks and standards.