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SYNTHESIS OF THE VULNERABILITY

An attacker can send a malformed GET query to Varnish, in order to
trigger a denial of service.

Impacted products: Varnish

Severity: 2/4

Creation date: 30/10/2013

DESCRIPTION OF THE VULNERABILITY

The Varnish error manager can indicate to restart VCL (vcl_recv)
when an error occurs :
sub vcl_error
return(restart);

An HTTP GET query should use the syntax "GET /page HTTP/1.1".
However, if the HTTP GET query only contains spaces, an assertion
occurs during the error processing.

An attacker can therefore send a malformed GET query to Varnish,
in order to trigger a denial of service.

ACCESS TO THE COMPLETE VIGIL@NCE BULLETIN

http://vigilance.fr/vulnerability/Varnish-denial-of-service-via-spaces-13675