Workstations and home PCs may not be as prone to attack as networks or
servers, but since they often contain sensitive information, such as
credit card information, they are targeted by system
crackers. Workstations can also be co-opted without the user's knowledge
and used by attackers as "slave" machines in coordinated attacks. For
these reasons, knowing the vulnerabilities of a workstation can save
users the headache of reinstalling the operating system.
2.4.2. Vulnerable Client Applications
Although an administrator may have a fully secure and patched server,
that does not mean remote users are secure when accessing it. For
instance, if the server offers Telnet or FTP services over a public
network, an attacker can capture the plain text usernames and
passwords as they pass over the network, and then use the account
information to access the remote user's workstation.
Even when using secure protocols, such as SSH, a remote user may be
vulnerable to certain attacks if they do not keep their client
applications updated. For instance, v.1 SSH clients are vulnerable to
an X-forwarding attack from malicious SSH servers. Once connected to
the server, the attacker can quietly capture any keystrokes and mouse
clicks made by the client over the network. This problem was fixed in
the v.2 SSH protocol, but it is up to the user to keep track of what
applications have such vulnerabilities and update them as necessary.
Chapter 4 Workstation Security discusses in more detail what steps administrators
and home users should take to limit the vulnerability of computer
workstations.
