CVE-2012-4445 in hostapd
Summary
by MITRE
Heap-based buffer overflow in the eap_server_tls_process_fragment function in eap_server_tls_common.c in the EAP authentication server in hostapd 0.6 through 1.0 allows remote attackers to cause a denial of service (crash or abort) via a small "TLS Message Length" value in an EAP-TLS message with the "More Fragments" flag set.
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Analysis
by VulDB Data Team • 12/29/2024
The vulnerability identified as CVE-2012-4445 represents a critical heap-based buffer overflow affecting the hostapd implementation of EAP authentication servers. This flaw exists within the eap_server_tls_process_fragment function located in the eap_server_tls_common.c source file, specifically impacting versions 0.6 through 1.0 of the hostapd software. The vulnerability manifests when processing EAP-TLS messages that contain a malformed "TLS Message Length" field while simultaneously having the "More Fragments" flag enabled, creating a scenario where malicious actors can exploit the authentication server's handling of fragmented TLS data.
The technical exploitation of this vulnerability stems from insufficient input validation within the TLS fragment processing logic. When an attacker crafts an EAP-TLS message with a deliberately small TLS Message Length value while maintaining the More Fragments flag, the hostapd server fails to properly validate the relationship between the declared message length and the actual fragment data. This discrepancy causes the application to allocate insufficient heap memory for the fragment processing, leading to buffer overflow conditions that result in memory corruption. The vulnerability operates at the protocol level within the Extensible Authentication Protocol framework, specifically targeting the TLS implementation used for secure authentication in wireless networks.
The operational impact of this vulnerability extends beyond simple denial of service, as it can potentially enable more sophisticated attacks depending on the environment. Remote attackers can trigger crashes or aborts in the authentication server, effectively disrupting wireless network access and authentication services. This disruption can lead to unauthorized network access attempts, authentication bypass scenarios, or complete service unavailability for legitimate users. The vulnerability affects wireless access points and authentication servers that rely on hostapd for EAP-TLS authentication, making it particularly dangerous in enterprise and public wireless network environments where continuous authentication services are critical.
Mitigation strategies for CVE-2012-4445 should prioritize immediate software updates to versions of hostapd that have patched this vulnerability, specifically versions 1.1 and later where the buffer overflow handling has been corrected. Network administrators should implement monitoring solutions to detect unusual EAP-TLS message patterns and malformed fragment sequences that could indicate exploitation attempts. Additionally, deploying intrusion detection systems with signatures specific to this vulnerability can help identify and block malicious traffic before it can cause service disruption. The vulnerability aligns with CWE-121, heap-based buffer overflow, and represents a technique that could be categorized under ATT&CK tactic TA0043, Resource Hijacking, as it consumes system resources through deliberate exploitation of memory handling flaws in authentication services.
Organizations should also consider implementing network segmentation and access controls to limit the potential impact of successful exploitation, ensuring that wireless authentication servers are properly isolated from critical network infrastructure. Regular security assessments of wireless network components and continuous monitoring of authentication server logs can help identify anomalous behavior patterns that may indicate exploitation attempts. The remediation process should include comprehensive testing of updated software in controlled environments before deployment to production systems to ensure that the patch does not introduce compatibility issues with existing wireless network configurations.