CVE-2007-1189 in Plan 9
Summary
by MITRE
Integer overflow in the envwrite function in the Alcatel-Lucent Bell Labs Plan 9 kernel allows local users to overwrite certain memory addresses with kernel memory via a large n argument, as demonstrated by (1) modifying the iseve function to gain privileges and (2) making the devpermcheck function grant unrestricted device permissions.
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Analysis
by VulDB Data Team • 08/25/2024
The vulnerability identified as CVE-2007-1189 represents a critical integer overflow flaw within the Alcatel-Lucent Bell Labs Plan 9 kernel implementation. This security weakness resides in the envwrite function where improper handling of the n argument parameter creates conditions for memory corruption. The flaw operates through a classic integer overflow scenario where a large input value causes the integer to wrap around, resulting in unexpected memory access patterns that can be exploited by local attackers. The vulnerability demonstrates a fundamental lack of input validation and bounds checking in kernel space operations, creating opportunities for privilege escalation and unauthorized system access.
The technical exploitation of this vulnerability leverages the integer overflow condition to manipulate memory addresses within kernel space. When a large n argument is passed to the envwrite function, the overflow allows attackers to overwrite specific memory locations that control critical kernel operations. This memory corruption can be strategically directed to modify the iseve function, which typically handles system events and privilege checks, enabling local users to gain elevated privileges within the system. Additionally, the vulnerability permits manipulation of the devpermcheck function, which is responsible for validating device permissions, allowing attackers to grant unrestricted access to system devices and resources.
The operational impact of this vulnerability extends beyond simple privilege escalation to encompass complete system compromise. Local attackers who can execute code on the system can leverage this flaw to bypass security controls and gain root-level access, potentially leading to full system control, data exfiltration, and persistent backdoor establishment. The nature of kernel-level vulnerabilities means that exploitation can result in system instability, denial of service, or complete system compromise. The attack surface is particularly concerning because it requires only local access to the system, making it accessible to users who already have legitimate system access but could leverage the vulnerability for unauthorized activities.
Security mitigations for CVE-2007-1189 should focus on implementing robust input validation and bounds checking within kernel functions that handle user-supplied parameters. The fix must address the specific integer overflow condition in the envwrite function by ensuring proper parameter validation and implementing overflow detection mechanisms before memory operations occur. System administrators should apply security patches promptly when available, as this vulnerability represents a known weakness in kernel implementations that has been documented for years. The vulnerability aligns with CWE-190, which specifically addresses integer overflow conditions, and represents a typical attack vector that could be mapped to ATT&CK technique T1068, involving privilege escalation through local exploitation of system vulnerabilities. Organizations should also implement monitoring for unusual memory access patterns and privilege changes that might indicate exploitation attempts. The vulnerability demonstrates the critical importance of kernel security and proper input validation in preventing local privilege escalation attacks that can compromise entire systems.