Re: SEC-Consult SA 20051025-0 :: Snoopy Remote Code Execution Vulnerability

["SEC Consult Research" <research () sec-consult com>]

On Thu, October 27, 2005 10:12 am, Florian Weimer said:
> Have you considered in your analysis that malicious servers might
> return HTTP redirects which contain suitable URLs?  This requires that
> the offsiteok member is set to true, though, because in the version I
> looked at, only http:// URLs are considered site-local.

Yes, I can confirm this. While I have not thought of this possibility, it
seems to boost the risk coming from the vulnerability.

I found the flaw during a review of Wordpress which uses MagpieRSS which
in turn uses Snoopy. As MagpieRSS is widly used, the concequence is that
any RSS feed-provider can replace the feed with a small redirect script,
exploiting the flaw with a crafted redirect https URL. Doing this with a
highly frequented RSS feed might result in many many servers being
simultaniously compromized. I might add that the offsiteok member defaults
to true and MagpieRSS does not seem to change that default value.

A notice to MagpieRSS has already been sent.

Daniel



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EOF Daniel Fabian / @2005
d.fabian at sec-consult dot com



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