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Improper Authentication


Severity High
Score 7.5/10


The identifier_hash for a session token in Atlassian Crowd before version 2.9.1 could potentially collide with an identifier_hash for another user or a user in a different directory, this allows remote attackers who can authenticate to Crowd or an application using Crowd for authentication to gain access to another user's session provided they can make their identifier hash collide with another user's session identifier hash.

  • HIGH
  • HIGH
  • NONE
  • LOW
  • HIGH
  • HIGH

CWE-287 - Improper Authentication

Improper (or broken) authentication attacks are widespread, and have accounted for many of the worst data breaches in recent years. Improper authentication attacks are a class of vulnerabilities where an attacker impersonates a legitimate user by exploiting weaknesses in either session management or credential management to gain access to the user’s account. This can result in disclosure of sensitive information, and can lead to system compromise, theft, identity theft, and fraud.


Advisory Timeline

  • Published