Security experts at Internet Security Systems (ISS) yesterday revealed the existence of a serious vulnerability in the Sendmail SMTP server software.
Sendmail is one of the most popular mail transfer agents on the internet, used extensively by large corporations and government agencies to route and deliver email.
The ISS X-Force team of security researchers said that in order to exploit this vulnerability, an attacker simply needs to be able to connect to the Sendmail SMTP server over a network. Exploitation of this vulnerability could allow remote attackers to take complete control of affected machines and obtain full access to users' emails, confidential information and other sensitive data.
By carefully timing the transmission of malicious data targeting this vulnerability, it is possible for a remote attacker to gain control of the affected system without requiring any user interaction.
"Due to its high popularity and extensive deployment throughout the internet, this vulnerability represents a serious risk to organizations that rely upon Sendmail for email services," said Gunter Ollmann, director of ISS X-Force. "Since SMTP is one of the few listening services allowed consistently through perimeter firewalls, we expect that many attackers will focus their efforts on developing techniques to exploit the vulnerability in order to gain entry into corporate and government networks."
Sendmail is primarily used in UNIX server environments, although various Windows versions also exist. A patch for this vulnerability is available from the Sendmail website.