Microsoft Internet Explorer DHTML Method Buffer Overflow Vulnerability



Date Discovered

February 8, 2005


Microsoft Internet Explorer is prone to a heap-based buffer-overflow vulnerability caused by a boundary condition error that is exposed when passing data to the 'createControlRange()' DHTML method. As a result, heap-based memory can be corrupted with attacker-supplied data. An attacker could exploit this issue to execute arbitrary code in the context of the currently logged-in user.

Technologies Affected

  • Microsoft Internet Explorer 5.0.1
  • Microsoft Internet Explorer 5.0.1 SP1
  • Microsoft Internet Explorer 5.0.1 SP2
  • Microsoft Internet Explorer 5.0.1 SP3
  • Microsoft Internet Explorer 5.0.1 SP4
  • Microsoft Internet Explorer 5.5
  • Microsoft Internet Explorer 5.5 SP1
  • Microsoft Internet Explorer 5.5 SP2
  • Microsoft Internet Explorer 6.0
  • Microsoft Internet Explorer 6.0 SP1
  • Microsoft Internet Explorer 6.0 SP2 do not use
  • Nortel Networks IP softphone 2050
  • Nortel Networks Mobile Voice Client 2050
  • Nortel Networks Optivity Telephony Manager (OTM)
  • Nortel Networks Symposium Web Center Portal (SWCP)
  • Nortel Networks Symposium Web Client


Run all software as a nonprivileged user with minimal access rights.
To limit the consequences of successful exploits, perform all nonadministrative tasks, such as browsing the web and reading email, as an unprivileged user with minimal access rights.

Do not follow links provided by unknown or untrusted sources.
Since this issue may be exploited via a malicious web page, users should be wary of following links provided by untrusted or unfamiliar sources.

Set web browser security to disable the execution of script code or active content.
Disable support for client-side scripting and active content in the Internet Zone. The vulnerable DHTML methods require client-side scripting to be invoked.

Modify default configuration files to disable any unwanted behavior.
Configuring email clients so that all email messages are displayed in plain-text format only may help close a malicious email attack vector.

Microsoft has released a cumulative update for Internet Explorer to address this and other vulnerabilities. Updates for Internet Explorer on Microsoft Windows 98/98SE/ME may be obtained through Windows Update. Nortel Networks has released security advisory 2005005511-2 acknowledging this issue. Please see the referenced advisory for more information.



Discovery is credited to Andreas Sandblad.

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