CVE-2016-8704 in Memcached
Summary
by MITRE
An integer overflow in the process_bin_append_prepend function in Memcached, which is responsible for processing multiple commands of Memcached binary protocol, can be abused to cause heap overflow and lead to remote code execution.
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Analysis
by VulDB Data Team • 04/20/2025
The vulnerability identified as CVE-2016-8704 represents a critical integer overflow flaw within the Memcached binary protocol implementation that exposes systems to remote code execution risks. This issue specifically affects the process_bin_append_prepend function, which handles multiple command processing within the Memcached server software. The flaw manifests when the system processes certain binary protocol commands that involve appending or prepending data, creating conditions where integer arithmetic operations exceed their valid range and wrap around to unexpected values.
The technical exploitation of this vulnerability stems from improper input validation and arithmetic handling within the binary protocol parser. When Memcached receives specially crafted binary protocol commands containing malformed length fields or size parameters, the process_bin_append_prepend function fails to properly validate integer values before performing memory allocation operations. This integer overflow condition results in heap memory corruption, where allocated buffers become oversized or under-sized, leading to memory layout disruptions that can be leveraged by attackers to manipulate heap metadata and control program execution flow.
From an operational impact perspective, this vulnerability poses significant risks to organizations relying on Memcached for caching and data storage operations. The remote code execution capability means that attackers can potentially execute arbitrary code on vulnerable systems with the privileges of the Memcached process, typically running as a low-privilege user but still capable of accessing sensitive data and system resources. The vulnerability affects widely deployed Memcached versions across various operating systems and network environments, making it particularly dangerous for internet-facing services that expose Memcached instances directly to untrusted networks without proper access controls or network segmentation.
The exploitation of CVE-2016-8704 aligns with ATT&CK techniques related to remote code execution and privilege escalation, specifically mapping to tactics involving command and control through protocol manipulation and memory corruption attacks. This vulnerability is categorized under CWE-190 as an integer overflow condition and demonstrates how improper integer handling in network protocol parsers can lead to severe security implications. Organizations implementing Memcached services should consider the broader implications of this vulnerability within their security posture, particularly regarding data confidentiality and system integrity. The flaw underscores the importance of proper input validation and memory management practices in network services, emphasizing that protocol implementation errors can have far-reaching consequences beyond simple denial-of-service conditions.
Mitigation strategies for this vulnerability include immediate deployment of patched Memcached versions from the vendor, implementing network segmentation to restrict direct access to Memcached instances, and applying firewall rules to limit exposure to trusted networks only. Additionally, organizations should consider implementing monitoring solutions to detect anomalous protocol behavior and potential exploitation attempts. The vulnerability serves as a reminder of the critical importance of validating all input parameters in network protocol implementations and demonstrates how seemingly minor arithmetic handling flaws can result in catastrophic security consequences, particularly in widely deployed caching systems that handle sensitive user data and application state information.