CVE-2016-3735 in Piwigo
Summary
by MITRE • 01/28/2022
Piwigo is image gallery software written in PHP. When a criteria is not met on a host, piwigo defaults to usingmt_rand in order to generate password reset tokens. mt_rand output can be predicted after recovering the seed used to generate it. This low an unauthenticated attacker to take over an account providing they know an administrators email address in order to be able to request password reset.
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Analysis
by VulDB Data Team • 01/30/2022
Piwigo represents a widely deployed image gallery platform written in php that serves millions of users globally for managing and sharing digital media collections. The vulnerability described in CVE-2016-3735 stems from a critical flaw in the password reset mechanism that directly compromises user account security. This issue manifests when the system fails to meet specific criteria during password reset operations, causing piwigo to fall back to using the mt_rand() function for token generation. The mt_rand() function in php is a pseudorandom number generator that produces predictable output sequences when the underlying seed value becomes known to an attacker. This fundamental weakness creates a significant security gap that can be exploited by unauthenticated threat actors to compromise user accounts. The vulnerability directly maps to CWE-330 Use of Insufficiently Random Values, which classifies weaknesses related to the use of predictable random number generators in security-sensitive contexts. An attacker requiring only an administrator's email address can initiate a password reset request and subsequently predict the generated token through reverse engineering of the mt_rand() seed value, thereby gaining unauthorized access to the compromised account. This vulnerability aligns with ATT&CK technique T1566.001 for credential access through phishing with a focus on account takeover. The operational impact extends beyond individual account compromise as successful exploitation can lead to full administrative control over the gallery, potentially enabling data exfiltration, content manipulation, and unauthorized access to user uploaded media. The attack vector remains particularly dangerous due to its unauthenticated nature, requiring no prior credentials or privileged access to begin the exploitation process. Organizations utilizing piwigo software face elevated risk of account takeover and data compromise when this vulnerability remains unpatched. The security implications become even more severe in environments where piwigo serves as a primary platform for sensitive content management, as the compromised accounts may have access to restricted media collections and user data. The predictability of mt_rand() outputs creates a cascading risk that can affect multiple users simultaneously if the same seed value is used across different reset operations. This vulnerability demonstrates the critical importance of implementing cryptographically secure random number generation in security-sensitive applications, particularly for session management and token generation. The flaw underscores the necessity of proper entropy sources and secure randomization techniques in web application development. Organizations should immediately implement patches addressing the random number generation weakness and consider implementing additional security controls such as rate limiting on password reset requests and enhanced monitoring for suspicious account activity. The vulnerability also highlights the importance of proper input validation and error handling in web applications, as the fallback behavior to mt_rand() indicates a lack of proper error recovery mechanisms. Security teams should prioritize this vulnerability in their assessment protocols and ensure that all instances of piwigo are updated to versions containing the appropriate fixes for this random number generation flaw.