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vulnerability announce 7402

Squid 2: denial of service via ICAP

Synthesis of the vulnerability

An authenticated attacker can force ICAP to consume all memory of proxy.
Impacted software: Squid, Squid ICAP.
Severity of this computer vulnerability: 1/4.
Consequences of a hack: denial of service on service.
Attacker's origin: user account.
Creation date: 11/12/2007.
Références of this announce: VIGILANCE-VUL-7402.

Description of the vulnerability

The ICAP protocol (Internet Content Adaptation Protocol, RFC 3507) permits to change the stream handling in the proxy, in order for example to transmit data to an antivirus.

When an user clicks on a file to download, but waits without indicating where to save it, data from file are transferred via ICAP but are not transmitted to the user. These temporary data are only stored in the memory.

An attacker can therefore request Squid to download a big file and wait for its data to exhaust the memory of proxy. The authenticated attacker can thus create a denial of service.
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