CVE-2004-1073 in Linux
Summary
by MITRE
The open_exec function in the execve functionality (exec.c) in Linux kernel 2.4.x up to 2.4.27, and 2.6.x up to 2.6.8, allows local users to read non-readable ELF binaries by using the interpreter (PT_INTERP) functionality.
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Analysis
by VulDB Data Team • 12/09/2024
The vulnerability described in CVE-2004-1073 represents a significant security flaw in the Linux kernel's executable loading mechanism that affects versions 2.4.x through 2.4.27 and 2.6.x through 2.6.8. This issue specifically targets the open_exec function within the execve system call implementation located in the exec.c file of the kernel source code. The flaw exploits a weakness in how the kernel handles executable binaries with non-readable permissions, creating an unexpected privilege escalation vector that allows local users to bypass normal file access controls.
The technical implementation of this vulnerability stems from the improper handling of program interpreter segments within ELF binaries during the execve system call execution. When a binary with a PT_INTERP segment (which specifies the dynamic linker or interpreter needed to execute the program) is loaded, the kernel's open_exec function fails to properly validate or restrict access to the interpreter binary even when the original executable file lacks read permissions. This creates a scenario where a local attacker can leverage the interpreter loading mechanism to access and read files that would normally be protected from reading due to their permission settings.
The operational impact of this vulnerability extends beyond simple information disclosure, as it fundamentally undermines the kernel's security model for executable loading. Attackers can exploit this weakness to read sensitive files that contain system information, configuration data, or potentially user credentials that should be protected by standard file permission mechanisms. The vulnerability is particularly concerning because it operates at the kernel level and requires no special privileges beyond local user access, making it a serious threat to system integrity and confidentiality.
This vulnerability maps directly to CWE-264, which addresses permissions, privileges, and access controls, specifically focusing on the improper handling of file access controls during program execution. From an attacker's perspective, this flaw aligns with techniques described in the ATT&CK framework under privilege escalation tactics, particularly the use of kernel exploits to gain elevated access. The vulnerability also relates to the broader category of information disclosure attacks that can be leveraged to gather intelligence for further exploitation attempts.
Mitigation strategies for this vulnerability require immediate kernel updates to versions that contain the appropriate patches addressing the open_exec function's improper access control handling. System administrators should prioritize patching affected systems and monitor for any suspicious execution patterns that might indicate exploitation attempts. Additionally, implementing proper file system permissions and using security modules like SELinux or AppArmor can provide additional layers of protection. Organizations should also conduct comprehensive security audits to identify systems running vulnerable kernel versions and ensure that all systems maintain current security patches to prevent exploitation of this and similar kernel-level vulnerabilities.