CVE-2013-4124 in Samba
Summary
by MITRE
Integer overflow in the read_nttrans_ea_list function in nttrans.c in smbd in Samba 3.x before 3.5.22, 3.6.x before 3.6.17, and 4.x before 4.0.8 allows remote attackers to cause a denial of service (memory consumption) via a malformed packet.
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Analysis
by VulDB Data Team • 06/30/2024
The vulnerability identified as CVE-2013-4124 represents a critical integer overflow flaw within the Samba file sharing implementation that affects multiple versions of the software. This issue resides in the nttrans.c file within the smbd daemon component, specifically within the read_nttrans_ea_list function. The vulnerability manifests when processing NT transaction extended attributes lists, creating a condition where an attacker can manipulate packet data to trigger unexpected behavior in the memory management system. The flaw allows remote attackers to exploit this condition and consume excessive memory resources, ultimately leading to denial of service conditions that can disrupt legitimate service operations. This vulnerability is particularly concerning as it affects Samba implementations across multiple version branches including 3.x, 3.6.x, and 4.x, making it widespread across many enterprise environments that rely on Samba for file sharing services.
The technical nature of this vulnerability falls under CWE-190, which specifically addresses integer overflow conditions that can lead to memory corruption and resource exhaustion. The flaw occurs when the read_nttrans_ea_list function processes extended attribute data structures without proper validation of integer values, allowing malicious input to cause arithmetic overflow during memory allocation calculations. When an attacker crafts a malformed packet containing oversized extended attribute values, the integer overflow results in incorrect memory allocation sizes being computed, leading to excessive memory consumption patterns. This vulnerability operates at the protocol level within the Server Message Block implementation, making it accessible through standard network connections to Samba services. The attack vector requires only network access to the affected Samba service and does not require authentication, making it particularly dangerous in environments where Samba servers are exposed to untrusted networks.
The operational impact of CVE-2013-4124 extends beyond simple denial of service conditions to potentially compromise entire network file sharing infrastructures. When exploited, the vulnerability causes the smbd daemon to consume escalating amounts of memory, leading to system resource exhaustion that can affect multiple concurrent users and applications. This memory consumption pattern can cause system instability, application crashes, and complete service unavailability for legitimate users. The vulnerability's impact is amplified in environments where Samba serves as a primary file sharing solution for large organizations, as the denial of service can cascade across multiple dependent systems. Network administrators may observe increasing memory usage patterns, system slowdowns, and eventual service failures that can be difficult to distinguish from legitimate resource demands. The vulnerability also presents challenges for intrusion detection systems that may not immediately recognize the pattern of memory consumption as an attack vector rather than normal system behavior.
Mitigation strategies for CVE-2013-4124 focus primarily on immediate software patching and system hardening measures. The most effective approach involves upgrading to patched versions of Samba where the integer overflow has been corrected through proper input validation and bounds checking. Organizations should prioritize patch management to ensure all Samba installations are updated to versions 3.5.22, 3.6.17, or 4.0.8 and later, depending on their current version branch. Network-level mitigations include implementing firewall rules to restrict access to Samba services to trusted networks only, and deploying intrusion detection systems that can monitor for anomalous memory consumption patterns. Additionally, system administrators should configure memory limits and monitoring alerts to detect unusual resource usage that might indicate exploitation attempts. The ATT&CK framework categorizes this vulnerability under the T1499.004 technique for network denial of service, emphasizing the importance of both defensive measures and monitoring capabilities. Regular security assessments and vulnerability scanning should be implemented to identify unpatched systems, as this vulnerability can remain undetected for extended periods in environments with insufficient monitoring controls.