Re: [exim-dev] Remote root vulnerability in Exim

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Author: Oli
To: exim-dev
Subject: Re: [exim-dev] Remote root vulnerability in Exim

Marc Haber wrote:
> On Thu, Dec 09, 2010 at 11:29:14AM +0000, Jeremy Harris wrote:
>> Alternatively, the Debian config uses HeaderX for transmission of
>> generated content, and expands it deliberately.
> We don't do such things. In fact, our configuration is amazingly like
> exim's stock config, it's only more automatic.
> Greetings
> Marc

Hi guys,

Please excuse me posting to the dev list as I'm not an Exim dev, but I
believe I have a couple of vulnerable servers and wanted an expert
opinion on some remedial action I've taken:

* Remounted /var with nosuid

* Added global config to limit the overall header size to 5k and
individual header lines to 512 bytes, using header_maxsize and

The first would only mitigate the current exploit, as it may be possible
to create suid binaries under somewhere like /tmp instead.

It was the second I'm interested in. Do you know if the bug which makes
the remote execution exploit possible is triggered before or after the
header size or line length is checked?

Thanks very much in advance.


Oli Comber
Systems Developer
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