Vulnerability Note VU#779243
EpubCheck 4.0.1 contains a XML external entity processing vulnerability
Original Release date: 13 Dec 2016 | Last revised: 14 Dec 2016

Overview
EpubCheck 4.0.1 is vulnerable to external XML entity processing attacks.

Description
EpubCheck is a tool to validate that EPUB files follow the proper format.
It can be used as a stand alone command line utility, or included in a project (most commonly being epub readers) as a library.
CWE-611: Improper Restriction of XML External Entity Reference (‘XXE’) – CVE-2016-9487
EpubCheck 4.0.1 does not properly restrict resolving external entities when parsing XML in EPUB files during validation.

An attacker who supplies a specially crafted EPUB file may be able to exploit this behavior to read arbitrary files, or have the victim execute arbitrary requests on his behalf, abusing the victim’s trust relationship with other entities.

Impact
A remote attacker may be able to access arbitrary files on a system, or cause the system execute arbitrary requests.

Solution
Apply an update
EpubCheck has released version 4.0.2 to address the vulnerability.

Vendor Information (Learn More)

VendorStatusDate NotifiedDate UpdatedAdobeAffected-13 Dec 2016
AppleAffected-14 Dec 2016
International Digital Publishing ForumAffected13 Oct 201609 Dec 2016If you are a vendor and your product is affected, let
us know.

CVSS Metrics (Learn More)

Group
Score
Vector

Base
6.8
AV:N/AC:M/Au:N/C:P/I:P/A:P

Temporal
5.9
E:–/RL:OF/RC:C

Environmental
4.5
CDP:N/TD:M/CR:ND/IR:ND/AR:ND

References

https://github.com/IDPF/epubcheck
http://idpf.org/epub
https://helpx.adobe.com/security/products/Digital-Editions/apsb16-45.html
https://support.apple.com/HT207432

Credit

Thanks to Craig Arendt for reporting this vulnerability.
This document was written by Trent Novelly.

Other Information

CVE IDs:
CVE-2016-9487

Date Public:
13 Dec 2016

Date First Published:
13 Dec 2016

Date Last Updated:
14 Dec 2016

Document Revision:
13

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