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Using OPIE

This document covers the setup and use of OPIE (One-time Passwords In Everything). This is a mechanism used by the ASF that ensures that your sudo password is not erroneously intercepted or pasted into the wrong prompt on the remote machine.

Note: Ubuntu VM's use ortpasswd (part of Orthrus).

All users in the wheel group (or in the $machine-sudoers in LDAP) have sudo access. In order to use sudo, a user must configure OPIE by running opiepasswd on the remote machine.

Getting an OPIE client for your computer

Using OPIE requires having an OPIE (S/Key) client on the local (trusted) machine. Some OPIE clients are:

  1. Debian/Ubuntu: See this forum thread
  2. Browser-based: otp-md5 tool in JavaScript
  3. SkeyCalc (Mac OS X)
  4. Orthrus (Unix-like; portable)
  5. FreeBSD: opiekey(1) is part of the base system
  6. donkey (Debian package donkey) Note: Use the '-f' option to set the hash type, usually 'donkey -f md5'

Setting up OPIE:

  1. pick a good passphrase, between 10 and 127 characters long.
  2. never expose it to the net, never type it on the remote machine
  3. run opiepasswd (or ortpasswd)on the remote machine you wish to get sudo access to.
  4. that will prompt you with an otp challenge, for instance: otp-md5 fo1834 470
  5. take that challenge string and run it locally on your workstation or using this ASF committer site
  6. enter your passphrase at the local prompt in 5
  7. repeat 5 and 6 until you are certain you entered your pw correctly
  8. paste the resulting six word response into the challenge prompt in 4. If you get a 20014 error, you have entered your password remotely by mistake, please contact infra if so.
  9. have someone add you to the 'wheel' group10. run sudo
  10. that will prompt you for an otp challenge
  11. repeat steps 5-8
  12. get root

An example:

Remote machine you want to get sudo access to: opiepasswd
You need the response from an OTP generator.
New secret pass phrase:

otp-md5 499 fo4576 <-- COPY THIS STRING Response:

Local machine:

$ otp-md5 499 fo4576
Using the MD5 algorithm to compute response.
Reminder: Don't use opiekey from telnet or dial-in sessions.
Enter secret pass phrase: foobarbaztwothirty

Remote machine:


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