Passwords in the Clear

[Editor's Draft] TAG Finding passwordsInTheClear-52,v 1.02 2006/12/12 21:52:21

Latest version:
This version:
Previous version(s):
David Orchard, BEA Systems mailto:dorchard@bea.com
Ed Rice, Hewlett Packard mailto:Ed.Rice@hp.com


The purpose of this finding is to clarify the security concerns around using passwords on the World Wide Web. Specifically, the objective is to point out that passwords SHOULD NOT be transmitted in the clear except in a few very specific cases.

Status of this Document

This document has been produced by the W3C Technical Architecture Group (TAG). This finding addresses TAG issue passwordsInTheClear-52.

This finding is an editorial draft, not yet accepted by the TAG. This finding therefore does not have any official standing and does not represent the consensus of the Technical Architecture Group at the W3C.

Additional TAG findings, both accepted and in draft state, may also be available. The TAG expects to incorporate this finding according to the process of the W3C Recommendation Track.

Please send comments on this finding to the publicly archived TAG mailing list www-tag@w3.org (archive).

Table of Contents

1 Introduction
2 Passwords in the clear
    a) Secure transfers
    b) SOAP Based transmissions.
3 Passwords displayed in Browser
A References

1 Introduction

Security on the World Wide Web is an important issue which needs to be addressed or mistrust of the Web will limit its growth potential. Specifically this paper talks about the use of passwords on the WWW and the needs to keep them secure during display, temporary storage in cookies as well as transmission of that data over the Web.

The TAG feels there are sufficient technologies available to take a clear stance on password security as it relates to the World Wide Web.

2 Passwords in the clear

This section addresses the issue of transmitting passwords in clear text over the World Wide Web. When a password is transmitted in clear text, it is vulnerable in many ways:

  1. The password is available on the wire. As the password is transmitted over the wire, tools such as packet sniffers or network analyzers can easily monitor the traffic and intercept passwords as they're sent between computers.
  2. The password is available in browsing history. Most web browsers allow you to navigate 'back' to previous pages, with content locally cached for performance as well as ease of use for the user. These pages are stored in memory and are relatively easy to examine.
  3. The password is readable on web proxies. Many larger corporations, as well as internet service providers, offer web proxies to allow users faster downloads as well as some level of anonymity for web users.

The HTTP specification specifically states that HTTP is not considered to be a secure method of user authentication (unless used in conjunction with some external secure systems such as SSL).

It is estimated that between 1 and 2 percent of e-commerce transactions are related to fraud. As customers are becoming more 'net savvy' they are starting to examine web page types and are attempting use only secure systems. Therefore it's imperative that any organization that wishes to safeguard its customers' data start with secure transfers of user login and password information.

Good Practice

A server or resource SHOULD NOT solicit any passwords in clear text.

Good Practice

A client or browser SHOULD NOT transmit passwords in clear text.

There are some cases where it is acceptable to transmit passwords in the clear; one example would be a test page that has no sensitive information on it where the only reason for the prompting of the password is to stop it from being indexed by a major search engine. Placing a password on the page is a simple way to stop the crawling of the pages without really having to 'secure' the content. Because users often cannot tell when a password is being send in the clear or not, we could use another 'Good Practice' to make sure that users are aware of the resulting vulnerability, and go on to use the same password again for a application intended to be secure.

However, many forms use onSubmit actions to start javascript programs. These programs secure the password and then transmit the password and other information. A User Agent cannot examine the javascript to ensure that the password is not transmitted in clear text. Therefore this finding can provide no Good Practice advice to User Agent authors.

2.1 Secure transfers

While it's not the purpose of this paper to do an exhaustive description of secure transfer methods on the Web, there are a few common methods used today which are easy to implement;

Digest Access Authentication[Digest]:

Digest acts as an extension to HTTP 1.0 and offers a way for authentication to happen between parties without transmitting the password over the network. Instead the password is treated as a secret input to a digest algorithm. The resulting digest is transmitted and verified by the server. Unfortunately the Digest method requires that both parties have access to the same initial secret value. Because most passwords are stored as a salted hash, it is not possible in practice for both parties to compute the same initial secret value.

Secure Socket Layer (SSL/TLS)

SSL/TLS is a protocol developed for transmitting private channels via the Internet. SSL/TLS works by using a private key to encrypt data that's transferred over the SSL/TLS connection. Most browsers support SSL/TLS and most sites which require credit card information use SSL/TLS today. Originally developed by Netscape there are now many different authorities providing private keys.

2.2 SOAP Based transmissions

SOAP communicates over HTTP and is subject to similar password security concerns. While SSL/TSL can be used to secure SOAP-based messages point to point, the issue can be more complex if SOAP intermediaries are used. The TAG's position on SOAP remains consistent: that passwords and sensitive information MUST be transmitted in a secure manner and not as clear text. If confidential information is to be sent as part of the SOAP package, publishers SHOULD either use SSL/TLS or XML Encryption for sensitive data elements. Further information on security for SOAP messages can be found in Security Challenges, Threats and Countermeasures Version 1.0 [WSI] or on the OASIS Web Services Security TC home page[WSS].

3 Passwords displayed in Browser

HTML allows authors to create input forms for multiple purposes. It is the TAG's opinion that if a form field is a password, password masking SHOULD take place to protect the user from onlookers seeing what is being entered and stop anyone from later using the 'back' button to discover passwords.

<form name="form1" action="http://www.mydomain.com/myform.cgi" method="POST">
    Enter Password : <input type="password" size="25"/>

Good Practice

User agents SHOULD use password masking when passwords are displayed in an HTML form.

This Good Practice does not contain a MUST because there are a few scenarios where password masking is not required. For example, the user may request that the password is displayed in the clear or the password is intended only to prevent search engine access.

A References

W3C Security Home

[Digest]: HTTP Authentication: Basic and Digest Access Authentication, RFC 2617, Draft Standard, IETF. Available online as http://www.ietf.org/rfc/rfc2617.txt.

[WSI]: Security Challenges, Threats and Countermeasures Version 1.0, WS-I. Available online as http://www.ws-i.org/Profiles/BasicSecurity/SecurityChallenges-1.0.pdf.

[WSS]: Oasis Web Services Security (WSS) TC.