CVE-2021-3864 : Exploit Details and Defense Strategies

A flaw was found in the way the dumpable flag setting was handled when certain SUID binaries executed its descendants. This could allow an unprivileged local user with an eligible root SUID binary to escalate privileges by placing core dumps into root-owned directories.

Understanding CVE-2021-3864

This CVE affects the kernel and involves improper access control due to mishandling of the dumpable flag setting.

What is CVE-2021-3864?

The vulnerability in CVE-2021-3864 arises from a flaw in how the dumpable flag setting is handled when specific SUID binaries execute their descendants. This can lead to unauthorized escalation of privileges.

The Impact of CVE-2021-3864

The exploitation of this vulnerability could result in unprivileged local users with access to an eligible root SUID binary gaining elevated privileges by manipulating core dump storage.

Technical Details of CVE-2021-3864

This section explores the vulnerability description, affected systems and versions, as well as the exploitation mechanism.

Vulnerability Description

The flaw occurs when a SUID binary with certain settings executes its descendants, ultimately leading to an incorrect dumpable value and potential privilege escalation.

Affected Systems and Versions

The vulnerability affects the kernel, and specific versions or distributions were not disclosed.

Exploitation Mechanism

By leveraging the mishandling of the dumpable flag setting in certain SUID binaries, an unprivileged local user could abuse core dump storage to gain access to root-owned directories.

Mitigation and Prevention

To address CVE-2021-3864, immediate steps should be taken with a focus on applying patches and implementing long-term security practices.

Immediate Steps to Take

It is crucial to monitor and update relevant software to prevent unauthorized escalation of privileges through core dump manipulation.

Long-Term Security Practices

Employing the principle of least privilege and regular security audits can help in identifying and addressing similar vulnerabilities.

Patching and Updates

Stay informed about security updates related to the affected systems to apply relevant patches promptly.