Debian: DSA 164-1 Severe: Mhonarc Cross Site Scripting Vulnerability

Jason Molenda and Hiromitsu Takagi found ways to exploit cross site
scripting bugs in mhonarc, a mail to HTML converter. When processing
maliciously crafted mails of type text/html, mhonarc, does not
deactivate all scripting parts properly. This is fixed in upstream
version 2.5.3.

If you are worried about security, it is recommended that you disable
support of text/html messages in your mail archives. There is no
guarantee that the mhtxthtml.pl library is robust enough to eliminate
all possible exploits that can occur with HTML data.

To exclude HTML data, you can use the MIMEEXCS resource. For example:


text/html
text/x-html


The use of "text/x-html" is probably not used any more, but is good to
include it, just-in-case.

If you are concerend that this could block out the entire contents of
some messages, then you could do the following instead:


text/html; m2h_text_plain::filter; mhtxtplain.pl
text/x-html; m2h_text_plain::filter; mhtxtplain.pl


This treats the HTML as text/plain.

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