CWE-6: J2EE Misconfiguration: Insufficient Session-ID Length
Description
The J2EE application is configured to use an insufficient session ID length.
If an attacker can guess or steal a session ID, then they may be able to take over the user's session (called session hijacking). The number of possible session IDs increases with increased session ID length, making it more difficult to guess or steal a session ID.
- Abstraction
- VariantA weakness tied to a specific language, technology or resource.
- Likelihood of exploit
- Not rated by MITRE
- Status
- Incomplete
Common consequences
- Access Control
Gain Privileges or Assume Identity
If an attacker can guess an authenticated user's session identifier, they can take over the user's session.
Potential mitigations
- Implementation
Session identifiers should be at least 128 bits long to prevent brute-force session guessing. A shorter session identifier leaves the application open to brute-force session guessing attacks.
- Implementation
A lower bound on the number of valid session identifiers that are available to be guessed is the number of users that are active on a site at any given moment. However, any users that abandon their sessions without logging out will increase this number. (This is one of many good reasons to have a short inactive session timeout.) With a 64 bit session identifier, assume 32 bits of entropy. For a large web site, assume that the attacker can try 1,000 guesses per second and that there are 10,000 valid session identifiers at any given moment. Given these assumptions, the expected time for an...