CVE-2021-22234 in Community Edition
Summary
by MITRE • 08/06/2021
An issue has been discovered in GitLab CE/EE affecting all versions starting with 13.11, 13.12 and 14.0. A specially crafted design image allowed attackers to read arbitrary files on the server.
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Analysis
by VulDB Data Team • 08/10/2021
CVE-2021-22234 represents a critical server-side request forgery vulnerability within GitLab Community and Enterprise editions that affects versions 13.11, 13.12, and 14.0. This vulnerability stems from insufficient input validation in the design image processing functionality, allowing attackers to manipulate file paths and access sensitive server resources through crafted image uploads. The flaw operates by leveraging the image processing pipeline to execute malicious file path traversal requests that bypass normal access controls and authorization mechanisms.
The technical implementation of this vulnerability resides in the improper handling of image file metadata and processing parameters within GitLab's web interface. When users upload design images, the system processes these files through a series of validation and rendering steps that fail to properly sanitize user-supplied file paths or image attributes. Attackers can craft malicious image files with specially formatted metadata or embedded references that, when processed by GitLab's image rendering engine, trigger unintended file system access operations. This vulnerability specifically impacts the image processing components that handle SVG and other vector graphics formats, which are commonly used in design workflows and project documentation.
The operational impact of CVE-2021-22234 extends beyond simple information disclosure, as it provides attackers with the ability to access arbitrary files on the server filesystem. This capability enables adversaries to extract sensitive configuration files, database credentials, private keys, and other confidential information stored on the GitLab server. The vulnerability can be exploited through the web interface without requiring authentication, making it particularly dangerous as it allows unauthenticated attackers to access server resources that should be restricted to authorized users only. Security researchers have noted that this flaw can lead to full system compromise when combined with other vulnerabilities or when attackers target specific sensitive files.
This vulnerability aligns with CWE-22, known as "Improper Limitation of a Pathname to a Restricted Directory," and maps to ATT&CK technique T1059.007 for "Command and Scripting Interpreter: Python" as attackers may leverage the compromised system to execute additional malicious code. The vulnerability also relates to ATT&CK technique T1566.002 for "Phishing: Spearphishing Attachment" as attackers can use this flaw to gain access to sensitive project data through compromised design files. Organizations using affected GitLab versions should immediately implement the official patches provided by GitLab, which include enhanced input validation and stricter file path handling in the image processing components. Additional mitigations should include network-level restrictions on image upload functionality, monitoring for unusual file access patterns, and implementing proper access controls to limit the impact of potential exploitation attempts.