Published:2012/08/30  Last Updated:2012/08/30

Adobe Reader fails to properly handle signatures


Adobe Reader fails to properly handle RSA signatures.

Products Affected

  • Adobe Reader 8.x and earlier


Adobe Reader contains an issue where it may fail to properly verify RSA signatures.


An attacker may be able to forge an RSA signature on a PDF document.


Update the software
Update to the latest version according to the information provided by the developer.

Note that this issue was resolved in Adobe Reader 9.

Vendor Status


  1. US-CERT Vulnerability Note VU#845620
    Multiple RSA implementations fail to properly handle signatures

JPCERT/CC Addendum

This JVN publication was delayed to 2012/8/30 after the developer fix was developed. From the fiscal year 2011, JPCERT/CC is using a new vendor coordination procedure. This new procedure came from the recommendation of the fiscal year 2010 "Study Group on Information System Vulnerability Handling" aimed at more timely JVN publications.

Vulnerability Analysis by JPCERT/CC

Analyzed on 2012.08.30

Measures Conditions Severity
Access Required can be attacked over the Internet using packets
  • High
Authentication anonymous or no authentication (IP addresses do not count)
  • High
User Interaction Required the user must be convinced to take a standard action that does not feel harmful to most users, such as click on a link or view a file
  • Mid
Exploit Complexity expertise and/or luck required (guessing correctly in medium-sized space, kernel expertise)
  • Low-Mid

Description of each analysis measures


Masahiko Takenaka of FUJITSU LABORATORIES LTD. reported this vulnerability to IPA.
JPCERT/CC coordinated with the developer under Information Security Early Warning Partnership.

Other Information

JPCERT Reports
CERT Advisory
CPNI Advisory
CVE CVE-2006-4339
JVN iPedia JVNDB-2012-000079