CVE-2016-0762 Observable Discrepancy in Apache Tomcat

Medium 5.9 Published Updated

Attackers can determine valid usernames via timing attacks in Apache Tomcat Realm implementations, potentially aiding further authentication bypass attempts.

Exploited in the wild
Not known
Login needed
Not needed
Attackable
Over the internet
Victim action needed
Not needed
Fix
Available

What is CVE-2016-0762?

CVE-2016-0762 is a medium-severity vulnerability in Apache Tomcat, published on 10 Aug 2017. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

The Realm implementations in Apache Tomcat versions 9.0.0.M1 to 9.0.0.M9, 8.5.0 to 8.5.4, 8.0.0.RC1 to 8.0.36, 7.0.0 to 7.0.70 and 6.0.0 to 6.0.45 did not process the supplied password if the supplied user name did not exist. This made a timing attack possible to determine valid user names. Note that the default configuration includes the LockOutRealm which makes exploitation of this vulnerability harder.

Weakness: CWE-203

Which versions are affected by CVE-2016-0762?

10 open source packages ship an affected version, including org.apache.tomcat:tomcat. It affects 15 products.

PackageAffectedFixed in
org.apache.tomcat:tomcat MavenFrom 6.0.06.0.46
org.apache.tomcat:tomcat MavenFrom 6.0.06.0.46
org.apache.tomcat:tomcat MavenFrom 7.0.07.0.72
org.apache.tomcat:tomcat MavenFrom 7.0.07.0.72
org.apache.tomcat:tomcat MavenFrom 8.0.0.RC18.0.37
org.apache.tomcat:tomcat MavenFrom 8.0.0.RC18.0.37
4 more packages
org.apache.tomcat:tomcat MavenFrom 8.5.08.5.5
org.apache.tomcat:tomcat MavenFrom 8.5.08.5.5
org.apache.tomcat:tomcat MavenFrom 9.0.0M19.0.0.M10
org.apache.tomcat:tomcat MavenFrom 9.0.0M19.0.0.M10

Products include Apache Tomcat, Canonical Ubuntu Linux, Debian Debian Linux, Netapp Oncommand Insight, Netapp Oncommand Shift, Netapp Snap Creator Framework and 9 more.

How do I fix CVE-2016-0762?

Upgrade org.apache.tomcat:tomcat to a fixed version for your release line: 6.0.46, 7.0.72, 8.0.37 or 8.5.5.

Is CVE-2016-0762 being exploited?

There is no known exploitation of CVE-2016-0762 in the wild and no public exploit code.

All Apache Tomcat vulnerabilities

Sources

Also known as GHSA-wxcp-f2c8-x6xv, UBUNTU-CVE-2016-0762.

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