CVE-2016-5408 in Red Hat
Summary
by MITRE
Stack-based buffer overflow in the munge_other_line function in cachemgr.cgi in the squid package before 3.1.23-16.el6_8.6 in Red Hat Enterprise Linux 6 allows remote attackers to execute arbitrary code via unspecified vectors. NOTE: this vulnerability exists because of an incorrect fix for CVE-2016-4051.
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Analysis
by VulDB Data Team • 09/13/2022
The vulnerability identified as CVE-2016-5408 represents a critical stack-based buffer overflow flaw within the squid web proxy caching system, specifically affecting the munge_other_line function in cachemgr.cgi. This issue manifests in Red Hat Enterprise Linux 6 systems running squid versions prior to 3.1.23-16.el6_8.6, creating a remote code execution pathway that adversaries can exploit from distant locations. The vulnerability's significance is compounded by its origins from an improper remediation of a previously addressed flaw, CVE-2016-4051, which demonstrates how inadequate security fixes can create new attack surfaces rather than resolving existing ones. The munge_other_line function processes data from cache manager interface requests, making it a prime target for attackers seeking to leverage memory corruption vulnerabilities.
The technical implementation of this buffer overflow occurs when the munge_other_line function handles input data without proper bounds checking, allowing attackers to write data beyond the allocated stack buffer space. This type of vulnerability falls under CWE-121, Stack-based Buffer Overflow, and specifically aligns with the ATT&CK technique T1059.007 for Command and Scripting Interpreter, as successful exploitation enables arbitrary code execution. The flaw typically occurs when processing cache manager requests that contain specially crafted input parameters, where the function fails to validate the length of incoming data against the fixed-size buffer it uses for processing. Attackers can manipulate the input to overwrite adjacent stack memory, potentially corrupting return addresses and function pointers, ultimately allowing them to redirect program execution flow to malicious code.
The operational impact of CVE-2016-5408 extends beyond simple remote code execution, as it can enable complete system compromise when exploited successfully. Since squid typically runs with elevated privileges to manage network caching operations, successful exploitation could provide attackers with root-level access to affected systems. This vulnerability particularly affects enterprise environments where squid serves as a critical caching proxy, potentially allowing attackers to intercept, modify, or redirect network traffic. The remote nature of the attack vector means that exploitation can occur from any location with network access to the vulnerable squid instance, making it an attractive target for widespread compromise campaigns. Organizations using squid as a caching solution face significant risk, especially when the proxy is exposed to untrusted networks or internet-facing services.
Mitigation strategies for CVE-2016-5408 require immediate system updates to patch versions of squid that properly address the buffer overflow vulnerability. Red Hat recommends upgrading to squid version 3.1.23-16.el6_8.6 or later, which contains the corrected implementation of the munge_other_line function. Additionally, network administrators should implement access controls to restrict access to the cache manager interface, as this reduces the attack surface for exploitation attempts. The implementation of proper input validation and bounds checking in the affected function demonstrates the importance of thorough code review processes, particularly when addressing security vulnerabilities. Organizations should also consider deploying intrusion detection systems that can identify suspicious patterns in cache manager interface traffic, as this may help detect exploitation attempts before successful compromise occurs. The vulnerability's relationship to CVE-2016-4051 underscores the necessity of comprehensive vulnerability management practices that ensure complete remediation rather than partial fixes that may introduce new security weaknesses.