Multiple Servlet Filter vulnerabilities have been fixed in Crowd Server and Data Center. These vulnerabilities also affect other Atlassian products. For more information, refer to Atlassian's security advisory.
A remote, unauthenticated attacker can bypass Servlet Filters used by first and third party apps. The impact depends on which filters are used by each app, and how the filters are used. Atlassian has released updates that fix the root cause of this vulnerability, but has not exhaustively enumerated all potential consequences of this vulnerability. Only the following attacks have been confirmed:
Authentication bypass. Sending a specially crafted HTTP request can bypass custom Servlet Filters used by third party apps to enforce authentication. A remote, unauthenticated attacker can exploit this to bypass authentication used by third party apps. Please note Atlassian has confirmed this attack is possible, but has not determined a list of all affected apps.
A remote, unauthenticated attacker can cause additional Servlet Filters to be invoked when the application processes requests or responses. Atlassian has confirmed and fixed the only known security issue associated with this vulnerability:
Cross-origin resource sharing (CORS) bypass. Sending a specially crafted HTTP request can invoke the Servlet Filter used to respond to CORS requests, resulting in a CORS bypass. An attacker that can trick a user into requesting a malicious URL can access the vulnerable application with the victim’s permissions.
- Versions < 4.3.8
- 4.4.x < 4.4.2
- 4.3.x >= 4.3.8
- 4.4.x >= 4.4.2
- Versions >= 5.0.1