Software Engineering Institute

Openfire 3.9.1, and possibly earlier versions, contains an uncontrolled resource consumption (CWE-400) vulnerability when using XMPP DEFLATE message compression. It has been reported that a highly compressed XMPP message of 4MB that uncompresses to 4GB may cause a resource exhaustion denial of service. The highly compressed XMPP messages may be sent in parallel to enhance the denial of service.

A remote unauthenticated attacker may be able to cause a denial-of-service condition.

We are currently unaware of a practical solution to this problem. A fix is available in the development branch of Openfire but a stable release is not available yet. Please consider the following workarounds.

Restrict Network Access

As a general good security practice, only allow connections from trusted hosts and networks if possible. Restricting access would prevent an attacker from connecting to the service from a blocked network location.

Disable XMPP Compression

Navigate to the menu Server -> Server Settings -> Compression Settings -> Client Compression Policy and check the option Not Available - Clients will not receive the option to use compressed traffic.