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Date: Sun, 27 Sep 2015 09:53:59 +0200
From: Pali Rohár <pali.rohar@...il.com>
To: oss-security@...ts.openwall.com
Subject: DoS attack through Email-Address perl module v1.907 (CVE id request)
Hello!
I discovered possible DoS attack in any software which uses
Email::Address perl module for parsing string input to list of email
addresses.
By default Email::Address module, version v1.907 (and all before) try to
understand nestable comments in input string with deep level 2.
Parsing nestable comments is for specially prepared inputs too slow and
can cause high CPU load, freezing application and Denial of Service.
Because input string for Email::Address module comes from external
source (e.g. from email sent by attacker) it is security problem all
software application which parse email messages by Email::Address perl
module. For example: RT: Request Tracker, CiderWebmail, ...
In new version v1.908 of Email::Address module, released at Sep 19 was
set default value of nestable comments to deep level 1. This is not
proper fix, just workaround for pathological inputs with nestable
comments. Probably nobody has normal usage for inserting nested comments
into email address in To:/Cc: headers...
https://metacpan.org/release/RJBS/Email-Address-1.908
https://github.com/rjbs/Email-Address/commit/3056b7d
Can you assign CVE id for this problem?
In attachment I'm sending example perl script which uses Email::Address
module for parsing From header and example input.
On my machine that script runs 5 seconds and it parse just four
addresses. Imagine that attacker send email with Cc: header with 10
times more addresses and Email::Address module effectively DoS server
where is that parser running...
--
Pali Rohár
pali.rohar@...il.com
View attachment "address-line" of type "text/plain" (324 bytes)
Download attachment "address-line-test.pl" of type "application/x-perl" (139 bytes)
Download attachment "signature.asc " of type "application/pgp-signature" (199 bytes)
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