CVE-2011-1745 in Linux
Summary
by MITRE
Integer overflow in the agp_generic_insert_memory function in drivers/char/agp/generic.c in the Linux kernel before 2.6.38.5 allows local users to gain privileges or cause a denial of service (system crash) via a crafted AGPIOC_BIND agp_ioctl ioctl call.
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Analysis
by VulDB Data Team • 11/06/2021
The vulnerability identified as CVE-2011-1745 represents a critical integer overflow flaw within the Linux kernel's AGP (Accelerated Graphics Port) subsystem. This issue resides in the agp_generic_insert_memory function located in drivers/char/agp/generic.c, affecting kernel versions prior to 2.6.38.5. The flaw manifests when processing AGPIOC_BIND ioctl commands, which are used to bind graphics memory to AGP devices. The integer overflow occurs during memory allocation calculations where insufficient bounds checking allows malicious input to cause arithmetic overflow conditions that can lead to unpredictable behavior.
The technical exploitation of this vulnerability leverages the fact that the agp_generic_insert_memory function fails to properly validate input parameters before performing arithmetic operations. When a local attacker submits a crafted AGPIOC_BIND ioctl call with malicious parameters, the kernel's integer overflow condition can result in memory corruption. This type of vulnerability falls under CWE-190, which specifically addresses integer overflow and underflow conditions, and represents a classic example of how improper input validation can lead to privilege escalation opportunities. The vulnerability operates at the kernel level, making it particularly dangerous as it can be exploited by any local user with access to the AGP subsystem.
The operational impact of this vulnerability extends beyond simple privilege escalation to include potential system crashes and denial of service conditions. When the integer overflow occurs, it can corrupt kernel memory structures or cause invalid memory access patterns that result in kernel panics and system crashes. This makes the vulnerability particularly concerning for server environments where system stability is paramount. The local nature of the exploit means that attackers do not require network access or special privileges beyond basic user access, making it a significant threat in multi-user environments where users might have access to graphics subsystems or AGP device interfaces.
From a cybersecurity perspective, this vulnerability aligns with ATT&CK technique T1068 which covers 'Exploitation for Privilege Escalation' and T1499 which addresses 'Endpoint Denial of Service'. The vulnerability demonstrates how low-level kernel flaws can be leveraged for both privilege escalation and system disruption, making it a prime target for attackers seeking persistent access or system compromise. Organizations should implement immediate patching strategies to address this vulnerability, as the kernel version 2.6.38.5 and later contain the necessary fixes. Additionally, system administrators should consider monitoring for suspicious AGP ioctl activity and implement proper access controls to limit user exposure to graphics subsystem interfaces where possible. The vulnerability underscores the importance of thorough input validation and bounds checking in kernel space operations, particularly when dealing with memory allocation functions that handle user-supplied parameters.