CVE-2022-1948 refers to a newly-identified security vulnerability in GitLab, affecting all versions starting from 15. up to and including 15... In these versions, the application lacks proper input validation for quick actions, allowing attackers to exploit cross-site scripting (XSS) vulnerabilities by injecting malicious HTML code into contact details. This post aims to provide an in-depth look at the vulnerability, how it can be exploited, as well as steps that can be taken to mitigate the risk.

Description of the vulnerability

Cross-site scripting (XSS) is a type of vulnerability that allows an attacker to inject malicious scripts into a web application and execute them in the browser of unsuspecting users. GitLab, a popular web-based DevOps lifecycle tool, has been found to be vulnerable to this type of attack due to a missing input validation mechanism in its quick actions feature.

In the affected GitLab versions, an attacker can manipulate the input fields that are used with quick actions (such as assigning issues, adding labels, and setting due dates) to store their malicious payload. Since GitLab does not properly validate this input, the malicious code can be executed when users view details about contacts.

The following is an example of a malicious quick action command

/assign @victim /label ~"xss" /due <img src=x onerror=alert('XSS')>2023-10-01

Whenever a user views the contact details after this quick action is executed, the malicious JavaScript code embedded within the due date input field (in this case, an image with an onerror attribute containing an alert) is executed, resulting in an XSS attack.

Original references and resources

- CVE Details: https://nvd.nist.gov/vuln/detail/CVE-2022-1948

- GitLab Security Release: https://about.gitlab.com/releases/2022/01/21/security-release-15--1-released/

- GitLab Documentation: https://docs.gitlab.com/ee/user/project/quick_actions.html

Exploit details

An attacker must have access to a GitLab instance and must have the ability to interact with quick actions to exploit the vulnerable versions of GitLab. In addition, the attacker needs to know the targeted user's GitLab username to mention them in a quick action command.

Wait for the targeted user to view the contact details impacted by the quick action command.

By following these steps, attackers can exploit the XSS vulnerability and execute arbitrary JavaScript code in the context of the victim's user session, potentially leading to account takeover, information disclosure, or other undesired results.

Mitigations and recommendations

The GitLab team has released a security update, version 15..1, which patches this vulnerability by adding proper input validation to the quick actions feature. It is strongly recommended to upgrade to GitLab 15..1 or a later version as soon as possible to protect against this vulnerability.

For users who are unable to upgrade their GitLab instance immediately, the following steps can help to mitigate the risk of an XSS attack:

Limit user access to the GitLab instance only to trusted personnel.

2. Educate users about the risk of XSS attacks and advise against clicking on untrusted or suspicious content.

Conclusion

CVE-2022-1948 is a serious security vulnerability affecting GitLab versions 15. to 15... By exploiting this vulnerability, attackers can execute malicious JavaScript code within the victim's user session, potentially leading to devastating consequences. To mitigate the risk, users are advised to upgrade to GitLab version 15..1 or later, and follow security best practices to minimize the risk of falling victim to an XSS attack.

Timeline

Published on: 07/28/2022 15:15:00 UTC
Last modified on: 08/04/2022 14:37:00 UTC