CVE-2009-1255 in Memcached
Summary
by MITRE
The process_stat function in (1) Memcached before 1.2.8 and (2) MemcacheDB 1.2.0 discloses (a) the contents of /proc/self/maps in response to a stats maps command and (b) memory-allocation statistics in response to a stats malloc command, which allows remote attackers to obtain sensitive information such as the locations of memory regions, and defeat ASLR protection, by sending a command to the daemon s TCP port.
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Analysis
by VulDB Data Team • 09/02/2019
The vulnerability described in CVE-2009-1255 represents a critical information disclosure flaw affecting Memcached and MemcacheDB software versions prior to 1.2.8 and 1.2.0 respectively. This vulnerability exposes sensitive system information through specially crafted statistics commands that can be issued over the network to the daemon's TCP port. The flaw specifically impacts the process_stat function within these applications, creating a pathway for remote attackers to gather detailed memory layout information and memory allocation statistics from the target system.
The technical implementation of this vulnerability leverages two distinct command interfaces that provide different types of sensitive information. The stats maps command reveals the contents of /proc/self/maps which contains memory mapping information including the base addresses of various memory regions, shared libraries, and executable segments. The stats malloc command exposes memory-allocation statistics that provide insights into heap organization and memory management patterns. Both of these data sources are fundamental to understanding the memory layout of a running process and are particularly valuable for attackers attempting to bypass modern security protections.
The operational impact of this vulnerability is severe and directly undermines several critical security mechanisms. The exposure of memory mapping information effectively defeats address space layout randomization (ASLR) protection, which is a core defense against memory corruption attacks. ASLR randomizes the memory locations of various program components to make exploitation of memory corruption vulnerabilities more difficult. However, when an attacker can obtain the exact memory addresses of system libraries and executable segments, they can effectively neutralize ASLR protections and proceed with more sophisticated attacks such as return-oriented programming (ROP) or direct code injection. This vulnerability essentially provides attackers with the information needed to craft more effective exploit payloads.
From a cybersecurity perspective, this vulnerability aligns with CWE-200, which describes "Information Exposure" and represents a classic example of information disclosure that can be leveraged for privilege escalation and attack chain progression. The vulnerability also maps to ATT&CK technique T1082, "System Information Discovery," as it enables adversaries to gather detailed system memory layout information. The remote nature of the attack means that an unauthenticated attacker can exploit this vulnerability from outside the network perimeter, making it particularly dangerous for systems that expose Memcached services to the internet.
The mitigation strategy for this vulnerability requires immediate patching of affected systems to versions that properly restrict access to these statistics commands. Organizations should implement network segmentation to limit access to Memcached services and ensure that only trusted systems can connect to the daemon's TCP port. Additionally, administrators should consider implementing firewall rules that restrict access to the Memcached port to specific IP addresses or ranges. The vulnerability demonstrates the importance of proper access control and the need for applications to validate and sanitize all input commands, particularly those that provide system-level information. Regular security audits should be conducted to identify and remediate similar information disclosure vulnerabilities in other network services and applications.