** DISPUTED ** Varnish 2.0.6 writes data to a log file without sanitizing non-printable characters, which might allow remote attackers to modify a window's title, or possibly execute arbitrary commands or overwrite files, via an HTTP request containing an escape sequence for a terminal emulator. NOTE: the vendor disputes the significance of this report, stating that "This is not a security problem in Varnish or any other piece of software which writes a logfile. The real problem is the mistaken belief that you can cat(1) a random logfile to your terminal safely."
Varnish is prone to a command-injection vulnerability because it fails to adequately sanitize user-supplied input in logfiles.
Attackers can exploit this issue to execute arbitrary commands in a terminal.
Varnish 2.0.6 is vulnerable; other versions may also be affected.
The following example is available:
echo -en "GET /\x1b]2;owned?\x07\x0a\x0d\x0a\x0d" > payload
nc localhost 80 < payload