CVE-2012-4678 in munin
Summary
by MITRE
munin-cgi-graph for Munin 2.0 rc4 does not delete temporary files, which allows remote attackers to cause a denial of service (disk consumption) via many requests to an image with unique parameters.
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Analysis
by VulDB Data Team • 02/20/2019
The vulnerability identified as CVE-2012-4678 affects munin-cgi-graph component within Munin monitoring software version 2.0 rc4, representing a significant security flaw that enables remote attackers to exploit disk space exhaustion through strategic manipulation of temporary file handling mechanisms. This issue specifically targets the temporary file management system within the CGI graph generation process, where the application fails to properly clean up generated temporary files after their intended use has concluded. The flaw manifests when attackers submit multiple requests to the image generation endpoint with unique parameters, causing the system to create numerous temporary files that persist in the filesystem without automatic deletion. This behavior directly violates proper resource management practices and creates a predictable avenue for denial of service attacks that can completely consume available disk space on the affected system.
The technical implementation of this vulnerability stems from inadequate temporary file cleanup logic within the munin-cgi-graph module, which operates under the assumption that temporary files will be automatically managed by the underlying operating system or filesystem cleanup mechanisms. However, the application's design fails to incorporate proper cleanup routines or garbage collection processes that would normally be expected in robust software applications. Each request with unique parameters triggers the creation of temporary files that remain on the filesystem indefinitely, as the application lacks mechanisms to identify and remove these files after their useful life has expired. This type of vulnerability aligns with CWE-319, which categorizes insecure temporary file handling as a weakness that can lead to resource exhaustion and denial of service conditions, particularly when the temporary files are created in predictable locations with predictable naming schemes.
The operational impact of CVE-2012-4678 extends beyond simple service disruption to potentially compromise the entire monitoring infrastructure that relies on Munin for system health tracking. When attackers exploit this vulnerability, they can rapidly consume available disk space through repeated requests, causing the system to become unresponsive and preventing legitimate monitoring operations from functioning properly. The attack vector is particularly dangerous because it requires minimal resources to execute and can be automated, allowing attackers to maintain sustained denial of service conditions. The vulnerability also impacts system stability by potentially causing cascading failures where the lack of available disk space affects other system processes that depend on proper filesystem operation. This type of attack directly maps to ATT&CK technique T1499.001, which covers resource exhaustion attacks through manipulation of file systems and temporary file handling mechanisms.
Mitigation strategies for CVE-2012-4678 should focus on implementing proper temporary file management practices and system hardening measures. Organizations should immediately apply the vendor-provided patch that addresses the temporary file cleanup functionality within munin-cgi-graph, ensuring that all temporary files are properly deleted after use or automatically cleaned up within a reasonable timeframe. System administrators should also implement monitoring solutions that track disk space utilization and alert on unusual patterns that may indicate exploitation attempts. Additional protective measures include configuring automated cleanup processes that regularly remove stale temporary files from the system, implementing request rate limiting to prevent abuse of the image generation endpoint, and ensuring that the munin-cgi-graph process runs with minimal required privileges to limit potential damage from exploitation. The vulnerability highlights the importance of proper resource management in web applications and serves as a reminder that even seemingly minor implementation flaws in temporary file handling can lead to significant security implications.