CVE-2012-2670 in Collabtive
Summary
by MITRE
manageuser.php in Collabtive before 0.7.6 allows remote authenticated users, and possibly unauthenticated attackers, to bypass intended access restrictions and upload and execute arbitrary files by uploading an avatar file with an accepted Content-Type such as image/jpeg, then accessing it via a direct request to the file in files/standard/avatar.
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Analysis
by VulDB Data Team • 02/17/2019
The vulnerability identified as CVE-2012-2670 affects Collabtive versions prior to 0.7.6 and represents a critical access control flaw that enables unauthorized file execution through avatar upload functionality. This issue stems from inadequate validation of file types and access restrictions within the manageuser.php component, creating a pathway for attackers to bypass intended security controls and execute malicious code on the target system. The vulnerability specifically targets the avatar upload mechanism, which should have been restricted to legitimate user profile images but was instead configured to accept executable content disguised as image files.
The technical implementation of this vulnerability involves a combination of content-type validation bypass and improper access control enforcement. Attackers can upload avatar files with accepted Content-Type headers such as image/jpeg while the system fails to properly validate the actual file content or enforce strict file extension checks. The flaw allows for arbitrary file execution because the system does not adequately verify that uploaded files conform to their declared content type or that they contain legitimate image data. This creates a scenario where malicious payloads can be embedded within what appears to be a standard image file, exploiting the trust placed in the Content-Type header validation.
The operational impact of this vulnerability extends beyond simple privilege escalation to encompass full system compromise potential. Remote authenticated users can leverage this flaw to upload malicious files that execute arbitrary code on the server, while unauthenticated attackers may also exploit the vulnerability if proper authentication requirements are bypassed or if the system allows guest access to avatar upload functionality. The direct access path through files/standard/avatar creates a persistent threat vector that remains active until the vulnerability is patched, potentially enabling attackers to establish backdoors, exfiltrate data, or use the compromised system as a launch point for further attacks within the network infrastructure.
This vulnerability aligns with CWE-22, which addresses improper limitation of a pathname to a restricted directory, and CWE-434, which covers unrestricted upload of file with dangerous type. The attack pattern follows ATT&CK technique T1078 for Valid Accounts and T1505 for Server Software Component, as it exploits legitimate user accounts to upload malicious content and leverages server-side component vulnerabilities to execute code. The flaw demonstrates a classic case of insufficient input validation combined with inadequate access control mechanisms, creating a dangerous combination that allows attackers to circumvent security controls through seemingly benign file upload functionality.
Organizations should implement immediate mitigations including strict file type validation, enforcement of filename extensions, removal of executable permissions from upload directories, and implementation of proper access controls for file retrieval paths. The vulnerability underscores the importance of defense-in-depth strategies where multiple layers of validation and access control work together to prevent such bypass scenarios. Regular security audits of file upload mechanisms and comprehensive testing of access control enforcement are essential to prevent similar vulnerabilities from being exploited in production environments.