Vulnerability Note VU#178560

Dallas Semiconductor iButton DS1991 vulnerable to dictionary attack

Original Release date: 06 May 2001 | Last revised: 21 Jun 2001


The Dallas Semiconductor iButton DS1991 is vulnerable to a dictionary attack, allowing an intruder to recover passwords.


The Dallas Semiconductor iButton DS1911 stores 1 kilobyte of data in 3 separate password-protected areas. It includes functionality intended to prevent passwords guessing, but is vulnerable to dictionary attacks. For more information, see the advisory published by @stake Research Labs, available at


Intruders can use a dictionary attack to recover passwords.


Use passwords not found in any dictionary of any language, rewrite your application, or upgrade to the DS1963S.

Systems Affected (Learn More)

VendorStatusDate NotifiedDate Updated
Dallas SemiconductorAffected-06 May 2001
If you are a vendor and your product is affected, let us know.

CVSS Metrics (Learn More)

Group Score Vector
Base N/A N/A
Temporal N/A N/A
Environmental N/A N/A



Our thanks to @stake Research Labs for the information contained in their advisory.

This document was written by Shawn V. Hernan.

Other Information

  • CVE IDs: Unknown
  • Date Public: 18 Jan 2001
  • Date First Published: 06 May 2001
  • Date Last Updated: 21 Jun 2001
  • Severity Metric: 8.73
  • Document Revision: 8


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