CVE-2016-3706 in C Library
Summary
by MITRE
Stack-based buffer overflow in the getaddrinfo function in sysdeps/posix/getaddrinfo.c in the GNU C Library (aka glibc or libc6) allows remote attackers to cause a denial of service (crash) via vectors involving hostent conversion. NOTE: this vulnerability exists because of an incomplete fix for CVE-2013-4458.
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Analysis
by VulDB Data Team • 08/23/2022
The CVE-2016-3706 vulnerability represents a critical stack-based buffer overflow within the GNU C Library's getaddrinfo function, specifically located in the sysdeps/posix/getaddrinfo.c file. This flaw affects the core system library that forms the foundation of network operations across numerous Unix-like operating systems and applications that rely on standard C library functions for hostname resolution. The vulnerability stems from an incomplete remediation of the previously addressed CVE-2013-4458, creating a persistent security gap that allows malicious actors to exploit the buffer overflow through hostent conversion processes. The root cause lies in improper bounds checking during the processing of network address information, where the getaddrinfo function fails to adequately validate input parameters before writing data to stack buffers.
The technical exploitation of this vulnerability occurs when remote attackers craft malicious network address resolution requests that trigger the flawed hostent conversion logic within getaddrinfo. During the execution of this function, the system attempts to convert hostent structures to address information, but due to insufficient buffer size validation, an attacker can overflow the stack buffer and potentially overwrite adjacent memory locations including return addresses and function pointers. This stack corruption leads to unpredictable program behavior and ultimately results in application crashes or system instability. The vulnerability demonstrates characteristics consistent with CWE-121 Stack-based Buffer Overflow, where insufficient bounds checking allows attackers to write beyond the allocated buffer boundaries.
The operational impact of CVE-2016-3706 extends beyond simple denial of service scenarios, as it can affect the stability of critical network services and applications that depend on glibc for address resolution. Systems running affected versions of glibc become vulnerable to remote exploitation, allowing attackers to disrupt network services, cause service outages, and potentially escalate privileges if the vulnerable applications execute with elevated permissions. The vulnerability affects a wide range of software including web servers, network daemons, mail servers, and any application that utilizes the standard getaddrinfo function for DNS resolution. From an adversarial perspective, this vulnerability aligns with ATT&CK technique T1071.004 for Application Layer Protocol: DNS, where attackers can leverage DNS resolution functions to achieve system compromise.
Mitigation strategies for this vulnerability require immediate patching of affected glibc versions, as the primary solution involves applying the complete fix that properly addresses the buffer overflow conditions in the getaddrinfo implementation. System administrators should prioritize updating their glibc installations to versions that contain the comprehensive remediation for both CVE-2013-4458 and CVE-2016-3706. Network-based mitigations can include implementing firewall rules to restrict DNS query traffic and monitoring for unusual patterns in address resolution requests that might indicate exploitation attempts. Additionally, application-level protections such as address space layout randomization and stack canaries can provide additional defense-in-depth measures, though these are not substitutes for the core library patching required to eliminate the vulnerability entirely. Organizations should also conduct thorough vulnerability assessments to identify any applications that might be indirectly affected by this vulnerability through their reliance on glibc functions.