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Date: Wed, 3 Jun 2015 14:43:35 -0400
From: Joshua Smith <>
Subject: Re: Re: Stack out of bounds read access in uudecode /

On Wed, Jun 03, 2015 at 08:25:37PM +0200, Hanno Böck wrote:
> Hi CVE-team,
> On Tue,  2 Jun 2015 22:35:02 -0400 (EDT)
> wrote:
> > What are the realistic scenarios in which this has a security impact?
> > 
> > For example, can any of these occur on actual systems?
> > 
> > 1. The attacker e-mails a uuencoded file to their own mailbox on a
> > web-based mail service. This service has a feature in which decoded
> > data is presented to the recipient. (The server operates on the data
> > with the uudecode program, not with any other implementation of the
> > uudecode algorithm. The attacker gains read access to unintended parts
> > of the server's memory.)
> > 
> > 2. A web site allows users to do HTTP uploads of data in uuencoded
> > format, and supports requests for decoded versions of the data. Same
> > parenthesized description as above.
> > 
> > 3. The attacker composes a news article with crafted uuencoded data
> > and posts it to the alt.sources Usenet newsgroup. The attacker is
> > subscribed to this newsgroup in their own account on a web-based
> > Usenet news reading service. Same parenthesized description as above.
> To answer these questions to the best of my knowledge: I don't know.
> This is a question I think I can answer in a very general fashion. I
> find and report these out of bounds vulns very often. I can
> confirm that in your described scenarios an attacker could trigger an
> out of bounds read. If that can in anyway be used to exfiltrate data or
> other attacks: I don't know. In this case it's probably unlikely,
> because as you can see the oob read is just one byte.
> Analyzing the impact of these kinds of vulns would require digging and
> understanding the code in detail by someone skilled in memory
> corruption exploitation (that means: not me).
> What I can say is that many very similar issues I reported in the past
> got CVEs (lately e.g. in wireshark and curl). And there'll probably be
> a lot more in the near future. I started trying to write up reports for
> all issues of these kinds I reported once they got fixed.
> If you prefere not to be bothered about out of bounds issues with
> unknown impact any more I am fine with that and will stop cc-ing. Also
> - if the people on oss-security feel that my reports on these
> minor issues are too frequently please tell me and I'll stop sending
> them. But in the past I had the impression it's apprechiated and solar
> designer wants as much info as possible in the oss-security archives
> in case external sources vanish.
> cu,
> -- 
> Hanno Böck
> mail/jabber:
> GPG: BBB51E42

Not that my opinion matters but I enjoy reading your posts on this and
similar vulnerabilities you have discovered.

Joshua Smith
Lead Systems Administrator WVNET

Montani Semper Liberi

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