CVE-2013-0179 in memcached
Summary
by MITRE
The process_bin_delete function in memcached.c in memcached 1.4.4 and other versions before 1.4.17, when running in verbose mode, allows remote attackers to cause a denial of service (segmentation fault) via a request to delete a key, which does not account for the lack of a null terminator in the key and triggers a buffer over-read when printing to stderr.
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Analysis
by VulDB Data Team • 01/31/2022
The vulnerability identified as CVE-2013-0179 represents a critical buffer over-read flaw in the memcached distributed memory object caching system. This issue specifically affects versions prior to 1.4.17 and manifests within the process_bin_delete function located in the memcached.c source file. The vulnerability becomes exploitable when memcached operates in verbose mode, a configuration typically used for debugging and monitoring purposes but which inadvertently creates conditions for malicious exploitation. The flaw arises from inadequate input validation and memory handling during key deletion operations, creating a scenario where remote attackers can trigger system instability through carefully crafted requests.
The technical root cause of this vulnerability stems from improper memory management when processing key deletion commands in verbose mode. When a client sends a delete request for a key, the process_bin_delete function attempts to print debugging information to stderr but fails to properly account for the absence of a null terminator in the key data structure. This omission leads to a buffer over-read condition where the program attempts to read beyond the allocated memory boundaries of the key buffer. The vulnerability is classified under CWE-121 as a stack-based buffer overflow, though the specific manifestation involves over-read rather than traditional overflow conditions. The flaw is particularly concerning because it can be triggered remotely without authentication, making it an attractive target for denial of service attacks that can crash the memcached service and disrupt legitimate operations.
The operational impact of CVE-2013-0179 extends beyond simple service disruption, as it can be leveraged to create persistent availability issues within systems relying on memcached for caching operations. When exploited successfully, the segmentation fault causes memcached to terminate abruptly, resulting in cache misses and increased load on backend databases as applications attempt to rebuild cached data. This cascading effect can significantly degrade system performance and potentially lead to complete service unavailability. The vulnerability aligns with ATT&CK technique T1499.004 for network denial of service attacks, as it specifically targets the availability aspect of the system through deliberate exploitation of memory corruption flaws. Organizations using memcached in production environments where verbose mode is enabled face particular risk, as the vulnerability can be exploited by any remote attacker with access to the memcached service port.
Mitigation strategies for this vulnerability primarily focus on immediate version upgrades to memcached 1.4.17 or later, which contain the necessary patches to address the buffer over-read condition. System administrators should also consider disabling verbose mode in production environments where it is not strictly required for operational debugging, as this reduces the attack surface for exploitation. Network-level protections can include implementing firewall rules to restrict access to memcached ports to trusted hosts only, and monitoring for unusual patterns of delete requests that might indicate exploitation attempts. Additionally, organizations should conduct regular security assessments of their caching infrastructure and ensure that all components are running patched versions to prevent similar vulnerabilities from being exploited. The vulnerability serves as a reminder of the importance of proper input validation and memory management in network services, particularly those handling user-supplied data in high-availability systems where service continuity is critical for business operations.