CVE-2022-23222 in Linux
Summary
by MITRE • 01/14/2022
kernel/bpf/verifier.c in the Linux kernel through 5.15.14 allows local users to gain privileges because of the availability of pointer arithmetic via certain *_OR_NULL pointer types.
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Analysis
by VulDB Data Team • 11/26/2024
The vulnerability identified as CVE-2022-23222 resides within the Linux kernel's eBPF (extended Berkeley Packet Filter) verifier component, specifically in the kernel/bpf/verifier.c file. This issue affects Linux kernel versions through 5.15.14 and represents a significant privilege escalation vulnerability that can be exploited by local attackers. The flaw stems from improper handling of pointer arithmetic operations involving certain *_OR_NULL pointer types, which creates an avenue for malicious code to bypass kernel security controls and elevate privileges to root level access.
The technical root cause of this vulnerability lies in the eBPF verifier's insufficient validation of pointer arithmetic operations when dealing with _OR_NULL pointer types. These pointer types are designed to represent pointers that may be null, but the verifier fails to properly restrict arithmetic operations on such pointers, allowing attackers to perform unauthorized pointer calculations. This weakness enables an attacker to manipulate memory addresses and potentially access kernel memory regions that should remain protected. The vulnerability specifically manifests when the verifier processes eBPF programs that utilize pointer arithmetic with _OR_NULL types, creating a path for privilege escalation through controlled memory manipulation.
From an operational perspective, this vulnerability poses a severe threat to Linux systems since it allows local users to gain root privileges without requiring external network access or complex exploitation techniques. The attack vector is particularly concerning because it only requires local system access, making it applicable to any system where users can execute eBPF programs or have access to systems with eBPF capabilities. Once exploited, the vulnerability enables complete system compromise, allowing attackers to execute arbitrary code with kernel-level privileges, potentially leading to data exfiltration, system persistence, or further network infiltration. The impact is amplified in environments where eBPF is widely used for network monitoring, security enforcement, or system performance analysis.
The vulnerability aligns with CWE-121, which addresses stack-based buffer overflow conditions, and relates to ATT&CK technique T1068, which covers 'Exploitation for Privilege Escalation'. Organizations should immediately implement mitigations including kernel updates to versions 5.15.15 or later where the vulnerability has been patched, disabling unnecessary eBPF functionality on systems where it is not required, and implementing monitoring for suspicious eBPF program loading activities. Additionally, system administrators should conduct thorough security audits to identify and restrict access to eBPF capabilities for non-privileged users, as well as implement proper access controls and privilege management policies to minimize potential attack surfaces. The patch addresses the core issue by strengthening the verifier's validation logic for pointer arithmetic operations, ensuring that *_OR_NULL pointer types cannot be used to perform unauthorized memory manipulation.