Two serious flaws that affect Windows, Mac OS X and Unix versions of Acrobat enable attackers to execute malicious code on a user's system via a PDF file distributed via e-mail.
Adobe Systems Inc. has warned of two
serious security flaws affecting Windows, Mac OS X and Unix versions of its
Acrobat software. The bugs could allow an attacker to execute malicious code on
a user's system via a PDF file distributed via e-mail, according to security
researchers.
The first flaw affects Version 6.0.2 of
Acrobat Reader, according to an advisory posted to the Bugtraq mailing list by security research firm
iDefense, which discovered both bugs. Reader incorrectly parses the .etd files
used in eBook transactions so that an .etd file containing special code in the
"title" or "baseurl" fields can cause an invalid memory access.
Adobe bolsters Reader in Version
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This could allow the execution of
malicious code with the privileges of the user, iDefense said. An attacker could
exploit this bug by sending an e-mail message including either an attached PDF
file or a link to the file.
Earlier versions of Acrobat Reader 6
may also be vulnerable, and Adobe Acrobat may also be affected, iDefense said.
Adobe has released Version 6.0.3 of both Acrobat and Reader for the Windows and
Mac OS X platforms, which fixes the problem.
iDefense said users can also protect
themselves by deleting the file: "C:\Program Files\Adobe\Acrobat
6.0\Reader\plug_ins\eBook.api." This doesn't affect the handling of PDF files,
but won't allow Acrobat or Reader to handle eBooks.
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A separate flaw has a similar effect on
Reader Version 5.0.9 for Unix, iDefense said. This flaw is found in Reader's
e-mail function, mailListIsPdf, and can be exploited in the same way as the
eBook bug. Adobe made it clear it isn't aware of any attempts to exploit the flaw, but recommended that
users update to
the newly released Acrobat Reader 5.0.10 "as a precaution."
iDefense added that previous versions
of Reader 5 for Unix are probably vulnerable. The company said Unix users can
get additional protection from an unofficial patch for the acroread shell script, which adds a check ensuring
that files passed to acroread are in fact PDF documents. The patch doesn't
protect against files opened manually from within Reader, iDefense said.
Secunia, an independent security
researcher that maintains a vulnerabilities database, gave the Unix flaw a
"highly critical" rating. Both bugs were discovered in mid-October, iDefense
said.
