CVE-2008-4445 in Linux
Summary
by MITRE
The sctp_auth_ep_set_hmacs function in net/sctp/auth.c in the Stream Control Transmission Protocol (sctp) implementation in the Linux kernel before 2.6.26.4, when the SCTP-AUTH extension is enabled, does not verify that the identifier index is within the bounds established by SCTP_AUTH_HMAC_ID_MAX, which allows local users to obtain sensitive information via a crafted SCTP_HMAC_IDENT IOCTL request involving the sctp_getsockopt function, a different vulnerability than CVE-2008-4113.
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Analysis
by VulDB Data Team • 05/26/2025
The vulnerability described in CVE-2008-4445 represents a critical buffer overflow flaw within the Linux kernel's Stream Control Transmission Protocol implementation, specifically affecting systems running kernel versions prior to 2.6.26.4. This issue resides in the sctp_auth_ep_set_hmacs function located in net/sctp/auth.c, which handles authentication operations for SCTP connections. The vulnerability arises from inadequate input validation when processing SCTP_HMAC_IDENT IOCTL requests, creating a potential information disclosure risk that can be exploited by local attackers with minimal privileges.
The technical flaw manifests as a missing bounds check on the identifier index parameter within the authentication handling code. When the SCTP-AUTH extension is enabled and a local user submits a crafted IOCTL request through the sctp_getsockopt function, the system fails to validate that the provided HMAC identifier index remains within the legitimate range defined by SCTP_AUTH_HMAC_ID_MAX. This oversight allows attackers to manipulate the index value beyond acceptable limits, potentially causing the kernel to read or write data beyond allocated memory boundaries. The vulnerability operates at the kernel level, making it particularly dangerous as it bypasses normal user-space protections and can lead to information leakage from kernel memory regions.
The operational impact of this vulnerability extends beyond simple information disclosure, as local attackers can potentially extract sensitive kernel memory contents including cryptographic keys, session data, and other confidential information. This type of vulnerability can be leveraged as a stepping stone for more sophisticated attacks, potentially enabling privilege escalation or further exploitation of the system. The vulnerability is classified under CWE-129 as an Improper Validation of Array Index, and aligns with ATT&CK technique T1068 which covers 'Exploitation for Privilege Escalation'. The attack vector requires local system access but does not require network connectivity, making it particularly concerning for systems where local privilege escalation is already possible or where users have access to kernel interfaces.
Mitigation strategies for CVE-2008-4445 primarily involve upgrading to kernel versions 2.6.26.4 or later where the bounds checking has been properly implemented. System administrators should also implement the principle of least privilege, limiting local user access to kernel interfaces and monitoring for unusual IOCTL activity. Additionally, organizations should maintain comprehensive patch management procedures to ensure timely deployment of security updates. The vulnerability demonstrates the critical importance of input validation in kernel space operations and serves as a reminder that even seemingly minor boundary checks can have significant security implications in operating system components. Regular security audits of kernel modules and authentication implementations should be conducted to identify similar validation gaps that could lead to information disclosure or privilege escalation attacks.