CVE-2012-3547 in Mac OS X Server
Summary
by MITRE
Stack-based buffer overflow in the cbtls_verify function in FreeRADIUS 2.1.10 through 2.1.12, when using TLS-based EAP methods, allows remote attackers to cause a denial of service (server crash) and possibly execute arbitrary code via a long "not after" timestamp in a client certificate.
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Analysis
by VulDB Data Team • 12/30/2024
The vulnerability identified as CVE-2012-3547 represents a critical stack-based buffer overflow flaw within the FreeRADIUS authentication server software. This issue affects versions 2.1.10 through 2.1.12 and specifically manifests within the cbtls_verify function that handles TLS-based EAP authentication methods. The vulnerability arises from insufficient input validation when processing client certificates, particularly when examining the "not after" timestamp field which indicates when a certificate expires. This flaw exists in the context of network authentication systems where FreeRADIUS serves as a central authentication server for wireless and wired network access control.
The technical implementation of this vulnerability stems from improper bounds checking in the certificate verification process. When a client presents a certificate containing an excessively long "not after" timestamp, the cbtls_verify function fails to properly validate the input length before copying data onto the stack. This results in a classic stack buffer overflow condition where attacker-controlled data overflows into adjacent stack memory locations. The flaw operates with a direct relationship to the certificate parsing logic and demonstrates poor defensive programming practices that violate fundamental security principles outlined in CWE-121. The vulnerability is particularly dangerous because it can be triggered remotely without authentication, making it an attractive target for attackers seeking to compromise network infrastructure.
The operational impact of this vulnerability extends beyond simple denial of service to potentially enabling remote code execution. An attacker who successfully exploits this vulnerability can cause the FreeRADIUS server to crash and terminate its services, creating a denial of service condition that disrupts network authentication. However, the more severe implications involve the possibility of arbitrary code execution on the server, which would allow an attacker to gain control of the authentication infrastructure. This represents a critical compromise of network security since FreeRADIUS typically serves as a central authentication point for enterprise networks, wireless access points, and VPN connections. The vulnerability directly relates to ATT&CK technique T1566.001 for credential access through phishing and T1071.004 for application layer protocol usage in network communication.
Mitigation strategies for CVE-2012-3547 require immediate patching of affected FreeRADIUS installations to versions 2.1.13 or later where the buffer overflow has been corrected. System administrators should also implement certificate validation policies that enforce reasonable timestamp constraints and monitor for unusual certificate patterns that might indicate exploitation attempts. Network segmentation and access controls should be implemented to limit exposure of FreeRADIUS servers to untrusted networks. Additionally, organizations should conduct comprehensive vulnerability assessments to identify other systems using vulnerable FreeRADIUS versions and ensure proper input validation is implemented in all certificate processing functions. The fix addresses the underlying CWE-121 stack buffer overflow issue through proper bounds checking and input validation mechanisms that prevent malicious data from overflowing into stack memory regions.