case insensitive password comparison

Project curl Security Advisory, November 2, 2016 - Permalink

VULNERABILITY

When re-using a connection, curl was doing case insensitive comparisons of user name and password with the existing connections.

This means that if an unused connection with proper credentials exists for a protocol that has connection-scoped credentials, an attacker can cause that connection to be reused if s/he knows the case-insensitive version of the correct password.

We are not aware of any exploit of this flaw.

INFO

The Common Vulnerabilities and Exposures (CVE) project has assigned the name CVE-2016-8616 to this issue.

CWE-178: Improper Handling of Case Sensitivity

AFFECTED VERSIONS

This flaw exists in the following curl versions.

• Affected versions: curl 7.7 to and including 7.50.3
• Not affected versions: curl < 7.7 and curl >= 7.51.0

libcurl is used by many applications, but not always advertised as such!

THE SOLUTION

In version 7.51.0, the comparisons are done case sensitively.

A patch for CVE-2016-8616 is available.

RECOMMENDATIONS

We suggest you take one of the following actions immediately, in order of preference:

A - Upgrade curl and libcurl to version 7.51.0

B - Apply the patch to your version and rebuild

TIME LINE

It was first reported to the curl project on September 23 by Cure53.

We contacted distros@openwall on October 19.

curl 7.51.0 was released on November 2 2016, coordinated with the publication of this advisory.

CREDITS

• Reported-by: Cure53
• Patched-by: Daniel Stenberg

This vulnerability was found during a Secure Open Source audit performed by Cure53.