Cisco Small Business Switches SSH Packet Processing Denial of Service Vulnerability

Cisco Small Business Switches contain a vulnerability that could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition to features that rely on SSH or SSL protocols.

The vulnerability is due to the processing flaw in malformed packets in the code used by SSH and SSL. An unauthenticated, remote attacker could exploit this vulnerability by sending malformed SSH or SSL packets to the device. An exploit could allow the attacker to cause a denial of service for the features requiring SSH or SSL support.

Cisco has confirmed this vulnerability and released updated software.

To exploit this vulnerability, an attacker must be able to send crafted SSH or SSL packets to the targeted device which may require the attacker to have access to trusted, internal networks, decreasing the likelihood of a successful attack.

The vulnerability does not affect the entire device. Features that need the SSL/TLS layer to encrypt data such as SSH, HTTPS, and Secure Sensitive Data are affected.

Cisco would like to thank Hisashi Kojima and Masahiro Nakada of Fujitsu Laboratories LTD for discovering this vulnerability.