CVE-2013-7424 in C Library
Summary
by MITRE
The getaddrinfo function in glibc before 2.15, when compiled with libidn and the AI_IDN flag is used, allows context-dependent attackers to cause a denial of service (invalid free) and possibly execute arbitrary code via unspecified vectors, as demonstrated by an internationalized domain name to ping6.
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Analysis
by VulDB Data Team • 12/22/2024
The vulnerability identified as CVE-2013-7424 represents a critical heap-based memory corruption issue within the GNU C Library glibc affecting versions prior to 2.15. This flaw manifests specifically when the getaddrinfo function processes internationalized domain names with the AI_IDN flag enabled, creating a dangerous condition that can be exploited by context-dependent attackers to execute arbitrary code or cause system denial of service. The vulnerability stems from improper handling of memory allocation and deallocation during DNS resolution of internationalized domain names, where the libidn library integration creates a path for malicious input to trigger invalid memory operations.
The technical root cause of this vulnerability lies in the improper management of memory structures within the getaddrinfo function when processing internationalized domain names. When the AI_IDN flag is set, the function attempts to handle Unicode domain names through the libidn library, but fails to properly validate or sanitize the input data. This leads to a situation where the system attempts to free memory that has either already been freed or was never allocated, resulting in an invalid free operation that can corrupt the heap memory layout. The vulnerability is particularly dangerous because it can be triggered through seemingly benign network operations such as ping6 commands targeting internationalized domain names, making it difficult to detect and prevent.
The operational impact of this vulnerability extends beyond simple denial of service to include potential arbitrary code execution, making it a severe threat to system security. Attackers can exploit this weakness by crafting malicious internationalized domain names that, when resolved through the vulnerable getaddrinfo function, trigger the invalid memory operations. The vulnerability affects systems using glibc versions before 2.15 and specifically when libidn is compiled into the library. This creates a wide attack surface since many network services and applications rely on the getaddrinfo function for DNS resolution, including web servers, email systems, and network utilities. The attack can be executed remotely without requiring authentication, making it particularly dangerous in networked environments where DNS resolution is frequently performed.
This vulnerability maps to CWE-415: Double Free and CWE-476: NULL Pointer Dereference within the Common Weakness Enumeration framework, representing a classic heap corruption scenario where improper memory management leads to exploitable conditions. From the MITRE ATT&CK framework perspective, this vulnerability could be leveraged through the T1210: Exploitation of Remote Services technique, where attackers exploit weaknesses in network services that perform DNS resolution. The attack chain typically involves sending a specially crafted internationalized domain name to a vulnerable system, causing the getaddrinfo function to execute the malformed memory operations. Organizations should prioritize patching their glibc installations to version 2.15 or later, implementing network segmentation to limit exposure, and monitoring for unusual DNS resolution patterns that might indicate exploitation attempts. Additionally, system administrators should disable unnecessary use of the AI_IDN flag in applications that do not require internationalized domain name support, reducing the attack surface for this particular vulnerability.