CVE-2017-18109 in Atlassian Crowd
Summary
by MITRE
The login resource of CrowdId in Atlassian Crowd before version 3.0.2 and from version 3.1.0 before version 3.1.1 allows remote attackers to redirect users to a different website which they may use as part of performing a phishing attack via an open redirect.
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Analysis
by VulDB Data Team • 08/17/2023
The vulnerability identified as CVE-2017-18109 represents a critical security flaw in Atlassian Crowd's authentication system that enables attackers to manipulate user redirection during the login process. This issue affects CrowdId implementations across multiple version ranges, specifically targeting versions prior to 3.0.2 and versions from 3.1.0 through 3.1.0, creating a window of exposure for organizations relying on this identity management platform. The vulnerability resides within the login resource component where user authentication flows are managed, making it a prime target for malicious actors seeking to compromise user security through social engineering techniques.
The technical implementation of this vulnerability stems from insufficient input validation and sanitization within the redirect parameter handling mechanism. When users attempt to authenticate through the CrowdId system, the application processes redirect URLs without adequate verification of their legitimacy. This flaw allows attackers to craft malicious URLs that contain crafted redirect parameters, which when clicked by authenticated users, will redirect them to attacker-controlled domains. The vulnerability aligns with CWE-601, which specifically addresses open redirect vulnerabilities where web applications fail to validate redirect destinations, and represents a classic example of how improper access control can be exploited for phishing attacks.
The operational impact of this vulnerability extends beyond simple redirection, creating a significant risk for organizations using Atlassian Crowd for identity management. Attackers can leverage this flaw to create convincing phishing pages that appear legitimate to users, potentially capturing credentials or other sensitive information from authenticated users. The attack vector is particularly dangerous because it exploits the trust users place in the Crowd authentication system, making it more likely for victims to fall for the deception. This vulnerability directly maps to ATT&CK technique T1566.001, which covers phishing attacks using malicious links, and represents a common attack pattern where authentication systems become the initial compromise vector for broader security breaches.
Organizations affected by this vulnerability should immediately implement several mitigation strategies to protect their users and systems. The most effective immediate solution involves upgrading to Atlassian Crowd versions 3.0.2 or 3.1.1, which contain the necessary patches to prevent unauthorized redirection. Additionally, security teams should implement network-level controls to monitor and block suspicious redirect patterns, while also conducting user awareness training to help identify potentially malicious redirection attempts. The vulnerability demonstrates the importance of input validation in authentication systems and highlights how seemingly minor flaws in redirect handling can create significant security risks. Organizations should also consider implementing additional authentication measures such as multi-factor authentication to provide defense-in-depth against credential theft attempts that may exploit this or similar vulnerabilities.