Published:2012/09/25  Last Updated:2012/09/25

ATOK for Android issue in the access permissions for the learning information file


ATOK for Android provided by JUST Systems, contains an issue in the access permissions for the learning information file.

Products Affected

  • ATOK for Android versions prior to 1.0.4
According to the developer, version information can be obtained through the following steps.
[Steps for checking version number]
By long touch "A1" at a screen where text can be entered, open ATOK Menu ->  tap ATOK Settings.
Check the version number towards the bottom.

Japanese text entering system ATOK
Ver.1.X.X  <-  this number is the version number
(C)2012 JUST Systems
* This issue is addressed in versions after Ver.1.0.4


ATOK for Android provided by JUST Systems contains an issue where another application may access the learning information file which stores user input strings.


If a user of the affected product uses other malicious Android application, the learning information file may be obtained.


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

Vendor Status

Vendor Link
JustSystems Corporation ATOK - Android Apps on Google Play (Japanese only)


JPCERT/CC Addendum

Vulnerability Analysis by JPCERT/CC

Analyzed on 2012.09.25

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 difficult or suspicious action. If the honest user must have elevated privileges, they are likely to be more suspicious
  • Low
Exploit Complexity some expertise and/or luck required (most buffer overflows, guessing correctly in small space, expertise in Windows function calls)
  • Mid-High

Description of each analysis measures


This analysis assumes that the user is tricked into installing a malicious application.


Gaku Mochizuki of Mitsui Bussan Secure Directions, Inc. reported this information to IPA.
JPCERT/CC coordinated with the developer under Information Security Early Warning Partnership.

Other Information

JPCERT Reports
CERT Advisory
CPNI Advisory
CVE CVE-2012-4016
JVN iPedia JVNDB-2012-000089