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Dallas Semiconductor iButton DS1991 vulnerable to dictionary attack

Vulnerability Note VU#178560

Original Release Date: 2001-05-06 | Last Revised: 2001-06-21


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.

Vendor Information

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Dallas Semiconductor

Updated:  May 06, 2001



Vendor Statement

No statement is currently available from the vendor regarding this vulnerability.

Vendor Information

The vendor has not provided us with any further information regarding this vulnerability.


For more information, see the @stake advisory.

If you have feedback, comments, or additional information about this vulnerability, please send us email.

CVSS Metrics

Group Score Vector
Base N/A N/A
Temporal N/A N/A
Environmental 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: None
Severity Metric: 8.73
Date Public: 2001-01-18
Date First Published: 2001-05-06
Date Last Updated: 2001-06-21 04:26 UTC
Document Revision: 8

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