The Cybersecurity and Infrastructure Security Agency (CISA) has added CVE-2022-0185, a critical heap-based buffer overflow vulnerability in the Linux kernel, to its Known Exploited Vulnerabilities Catalog. This vulnerability, found in the legacy_parse_param function of the Linux kernel’s Filesystem Context functionality, allows local users to escalate their privileges, posing a significant security threat to systems running affected versions of the Linux kernel. Given the widespread use of Linux in various environments, immediate attention and remediation are required to mitigate potential exploitation.
Vulnerability Overview
- CVE ID: CVE-2022-0185
- Vulnerability Type: Heap-Based Buffer Overflow
- CWE: CWE-190 (Integer Overflow or Wraparound)
- Affected Product: Linux Kernel
- Affected Versions:
- Linux Kernel version 8.4 (and potentially other versions where the flaw exists)
- Impact: Privilege escalation, unauthorized access, potential full system compromise.
Technical Details
CVE-2022-0185 is a heap-based buffer overflow vulnerability in the Linux kernel, specifically within the legacy_parse_param function associated with the Filesystem Context functionality. This flaw occurs when the function fails to properly verify the length of parameters supplied by the user. If an unprivileged local user has the capability to open a filesystem that does not support the Filesystem Context API (causing it to fall back to legacy handling), they can exploit this flaw to escalate their privileges on the system.
The vulnerability is particularly concerning in environments where unprivileged user namespaces are enabled, as it allows attackers to execute the exploit without requiring elevated privileges. In other cases, the attacker would need the CAP_SYS_ADMIN capability within a namespace to trigger the vulnerability.
Exploitation in the Wild
CVE-2022-0185 has been observed in the wild, with attackers leveraging this vulnerability to gain unauthorized access and escalate privileges on vulnerable systems. The availability of exploit code and detailed technical write-ups has increased the risk of widespread exploitation, especially in environments that have not yet applied the necessary patches.
Mitigation and Recommendations
Immediate Actions:
- Patch Management: Organizations running affected versions of the Linux kernel should apply the latest security patches to mitigate the risk associated with CVE-2022-0185. The relevant fix is included in Linux kernel updates, which should be applied as soon as possible.
- Access Controls: Restrict the ability of unprivileged users to create and manage user namespaces where possible. This reduces the attack surface by limiting the ability of non-administrative users to exploit the vulnerability.
- Kernel Hardening: Consider implementing additional kernel hardening techniques such as disabling unprivileged user namespaces or using security modules like SELinux or AppArmor to reduce the potential impact of any successful exploitation.
Long-Term Recommendations:
- Regular Security Audits: Conduct regular security audits of your systems to ensure that all components, especially the kernel, are up to date and properly configured.
- Monitoring and Detection: Implement monitoring solutions to detect unusual or unauthorized activity that may indicate an attempt to exploit CVE-2022-0185. This includes monitoring for processes being run by unprivileged users that should not have access to certain system functions.
- Incident Response Readiness: Prepare an incident response plan specific to kernel vulnerabilities, ensuring that your team can quickly respond to potential exploitation and mitigate any damage.
CVE-2022-0185 represents a significant risk to Linux-based systems due to its potential for privilege escalation through a heap-based buffer overflow. The vulnerability has been actively exploited, making it critical for organizations to apply the necessary patches and reinforce their security posture to protect against potential attacks. With Linux being a core component of many enterprise environments, timely action is essential to safeguarding systems from this and similar vulnerabilities.
By addressing CVE-2022-0185 with the appropriate patches and security practices, organizations can protect their Linux-based systems from exploitation and ensure the continued security and stability of their environments.
