CVE-2015-5180 in Fujitsu M10-1
Summary
by MITRE
res_query in libresolv in glibc before 2.25 allows remote attackers to cause a denial of service (NULL pointer dereference and process crash).
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Analysis
by VulDB Data Team • 08/16/2024
The vulnerability identified as CVE-2015-5180 resides within the res_query function of libresolv, a critical component of the GNU C Library glibc that handles DNS resolution operations. This flaw affects versions of glibc prior to 2.25 and represents a classic null pointer dereference vulnerability that can be exploited by remote attackers to trigger arbitrary process crashes. The issue manifests when the res_query function processes malformed DNS responses or specific query patterns that lead to improper memory handling within the DNS resolution subsystem.
The technical implementation of this vulnerability involves the res_query function's failure to properly validate input parameters and response structures from DNS servers. When processing certain malformed DNS responses, the function attempts to dereference a null pointer that should have been properly initialized or validated. This condition occurs during the parsing of DNS resource records where the expected data structures contain null references that are subsequently accessed without proper null checks. The flaw operates at the intersection of network protocol handling and memory management, making it particularly dangerous as it can be triggered through normal DNS query operations.
From an operational perspective, this vulnerability presents a significant denial of service risk that can be exploited by remote attackers without requiring authentication or special privileges. The impact extends beyond simple service disruption as the process crash can potentially affect the stability of applications and systems that rely on DNS resolution for their operation. Attackers can craft malicious DNS responses or exploit specific query patterns to trigger the null pointer dereference, causing the targeted process to terminate unexpectedly. This vulnerability particularly affects systems that use the standard glibc DNS resolution functions, making it widespread across Unix-like operating systems and applications that depend on the underlying DNS infrastructure.
The vulnerability maps to CWE-476 which specifically addresses NULL pointer dereference conditions, and aligns with several ATT&CK techniques including T1499.004 for network denial of service and T1595.001 for network scanning. Organizations using affected glibc versions face potential disruption to critical services that depend on DNS resolution, including web servers, mail systems, and application services that may experience cascading failures when processes crash due to this vulnerability. The exploitability of this vulnerability is relatively straightforward, requiring only the ability to influence DNS responses or craft specific queries that trigger the problematic code path.
Mitigation strategies for CVE-2015-5180 primarily involve upgrading to glibc version 2.25 or later where the vulnerability has been addressed through proper null pointer validation and input sanitization. System administrators should also implement DNS security measures including DNSSEC validation, DNS query filtering, and monitoring for unusual DNS traffic patterns that might indicate exploitation attempts. Additionally, network segmentation and firewall rules can help limit the potential impact of DNS-based attacks by restricting access to DNS servers and implementing rate limiting for DNS queries. Organizations should conduct thorough testing of glibc upgrades in controlled environments to ensure compatibility with existing applications before deployment to production systems.