exploit the possibilities

Skype Client For Mac Chat Unicode Denial Of Service

Skype Client For Mac Chat Unicode Denial Of Service
Posted Jun 23, 2010
Authored by Marc Ruef | Site scip.ch

The Skype client for Mac Chat suffers from a unicode related denial of service vulnerability.

tags | advisory, denial of service
MD5 | ae2d11a30d493bed1fd8679fd6948bb5

Skype Client For Mac Chat Unicode Denial Of Service

Change Mirror Download
Skype Client for Mac Chat Unicode Denial of Service

scip AG Vulnerability ID 4142 (06/22/2010)
http://www.scip.ch/?vuldb.4142

I. INTRODUCTION

Skype is a very popular proprietary voice-over-ip client available for
multiple platforms.

More information is available on the official web site at the following URL:

http://www.skype.com

II. DESCRIPTION

Marc Ruef at scip AG found a denial of service vulnerability in the
current release for Apple MacOS X (version 2.8).

The application provides the possibility of sending messages to other
Skype users via the embedded chat feature.

If a vulnerable client receives a malicious message, the message and all
further messages will be received but not displayed.

It was not possible to reproduce this behavior on different version of
the Skype client for Windows. On the iPhone (Version 1.3.0.275 on iPhone
3gs) the behavior is different. A received message containing the
malicious string is shown but the content not displayed. Instead the
message box contains the hint that the message has been deleted. No
further impact could be determined.

III. EXPLOITATION

Information on how to exploit this vulnerability is included in the
initial bug report.

An attacker has to include Unicode characters in the text message sent
to the victim. The characters used for the proof-of-concept are out of
Mathematical Alphanumeric Symbols (1D400-1D7FF)

An automated toolkit to exploit this vulnerability is available but has
not been disclosed so far.

IV. IMPACT

After receiving a malicious message the attacked client is not able to
use the chat feature anymore.

Furthermore, the handling of some other elements of the application are
not possible anymore (e.g. review the chat history).

V. DETECTION

For a common environment the identification of the attack is possible
after a successful exploitation only.

Deep inspection of received data communication over the Skype channel
may be able to determine an ongoing attack attempt.

VI. SOLUTION

No workaround or solution known at the moment.

It is suggested to allow incoming chat messages from approved friends only.

VII. VENDOR RESPONSE

This issue has been posted on Jira the public issue tracking and
reporting system of Skype.

The vendor verified the existence of the issue. No further information
about bugfixing were published.

VIII. SOURCES

scip AG - Security is our Business (german)
http://www.scip.ch/

scip AG - Vulnerability Database (german)
http://www.scip.ch/?vuldb.4142

computec.ch Document Database (german)
http://www.computec.ch

Skype Jira - Original Bug Report
http://developer.skype.com/jira/browse/SCM-681

IX. DISCLOSURE TIMELINE

2010/05/09 Identification of the vulnerability
2010/05/10 Notification of Skype via Jira (bug tracking)
2010/05/11 Acknowledgement of the issue via Jira
2010/05/11 Providing step-by-step exploit procedure
2010/06/22 Public disclosure of the advisory

X. CREDITS

The vulnerability has been discovered by Marc Ruef.

Marc Ruef, scip AG, Zuerich, Switzerland
maru-at-scip.ch
http://www.scip.ch

Additional testing and help was provided by Stefan Friedli and Martin Burke.

A1. LEGAL NOTICES

Copyright (c) 2002-2010 scip AG, Switzerland.

Permission is granted for the re-distribution of this alert. It may not
be edited in any way without permission of scip AG.

The information in the advisory is believed to be accurate at the time
of publishing based on currently available information. There are no
warranties with regard to this information. Neither the author nor the
publisher accepts any liability for any direct, indirect or
consequential loss or damage from use of or reliance on this advisory.
Login or Register to add favorites

File Archive:

November 2020

  • Su
  • Mo
  • Tu
  • We
  • Th
  • Fr
  • Sa
  • 1
    Nov 1st
    2 Files
  • 2
    Nov 2nd
    9 Files
  • 3
    Nov 3rd
    15 Files
  • 4
    Nov 4th
    90 Files
  • 5
    Nov 5th
    22 Files
  • 6
    Nov 6th
    16 Files
  • 7
    Nov 7th
    1 Files
  • 8
    Nov 8th
    1 Files
  • 9
    Nov 9th
    40 Files
  • 10
    Nov 10th
    27 Files
  • 11
    Nov 11th
    28 Files
  • 12
    Nov 12th
    13 Files
  • 13
    Nov 13th
    18 Files
  • 14
    Nov 14th
    2 Files
  • 15
    Nov 15th
    2 Files
  • 16
    Nov 16th
    29 Files
  • 17
    Nov 17th
    15 Files
  • 18
    Nov 18th
    15 Files
  • 19
    Nov 19th
    21 Files
  • 20
    Nov 20th
    16 Files
  • 21
    Nov 21st
    1 Files
  • 22
    Nov 22nd
    0 Files
  • 23
    Nov 23rd
    19 Files
  • 24
    Nov 24th
    32 Files
  • 25
    Nov 25th
    9 Files
  • 26
    Nov 26th
    11 Files
  • 27
    Nov 27th
    15 Files
  • 28
    Nov 28th
    9 Files
  • 29
    Nov 29th
    0 Files
  • 30
    Nov 30th
    0 Files

Top Authors In Last 30 Days

File Tags

Systems

packet storm

© 2020 Packet Storm. All rights reserved.

Services
Security Services
Hosting By
Rokasec
close