CVE-2021-3139 : Exploit Details and Defense Strategies

A vulnerability in Open-iSCSI tcmu-runner versions 1.3.x to 1.5.2 allows remote attackers to read or write files via directory traversal in an XCOPY request.

Understanding CVE-2021-3139

This CVE identifies a security issue in the Open-iSCSI tcmu-runner that can be exploited by attackers to access files using a specific XCOPY request.

What is CVE-2021-3139?

In Open-iSCSI tcmu-runner 1.3.x to 1.5.2, a missing check for transport-layer restrictions in the xcopy_locate_udev function enables attackers to perform unauthorized file operations through directory traversal, potentially leading to data breaches.

The Impact of CVE-2021-3139

The vulnerability poses a significant risk as attackers can leverage it to exploit network access to an iSCSI LUN, compromising data integrity and confidentiality.

Technical Details of CVE-2021-3139

This section delves into the specific technical aspects of the CVE to better understand its implications and necessary mitigation strategies.

Vulnerability Description

The flaw lies in the tcmur_cmd_handler.c file, allowing malicious actors to circumvent transport-layer restrictions and gain unauthorized access to files, presenting a severe security concern for systems running the affected versions of tcmu-runner.

Affected Systems and Versions

Open-iSCSI tcmu-runner versions 1.3.x through 1.5.2 are susceptible to this vulnerability, potentially exposing a wide range of systems to exploitation if left unaddressed.

Exploitation Mechanism

Remote threat actors can abuse the lack of transport-layer checks in the xcopy_locate_udev function to orchestrate file-related attacks, compromising the confidentiality and integrity of sensitive information stored on affected systems.

Mitigation and Prevention

Understanding the severity of CVE-2021-3139 is crucial in implementing immediate steps to secure vulnerable systems and prevent unauthorized access.

Immediate Steps to Take

System administrators are advised to apply security patches promptly, monitor network activities for suspicious behavior, and restrict access to vulnerable systems to mitigate the risk of exploitation.

Long-Term Security Practices

Implementing network segmentation, regularly updating system software, and conducting security audits can help enhance the overall security posture of an organization, safeguarding against potential threats such as CVE-2021-3139.

Patching and Updates

Stay informed about security advisories and updates released by the Open-iSCSI community, ensuring that the latest patches are applied to eliminate the identified vulnerability and fortify system defenses.