[SECURITY] [DLA 2133-1] tomcat7 security update

Package : tomcat7
Version : 7.0.56-3+really7.0.100-1
CVE ID : CVE-2019-17569 CVE-2020-1935 CVE-2020-1938

Several security vulnerabilities have been discovered in the Tomcat
servlet and JSP engine.

CVE-2019-17569

The refactoring in 7.0.98 introduced a regression. The result of
the regression was that invalid Transfer-Encoding headers were
incorrectly processed leading to a possibility of HTTP Request
Smuggling if Tomcat was located behind a reverse proxy that
incorrectly handled the invalid Transfer-Encoding header in a
particular manner. Such a reverse proxy is considered unlikely.

CVE-2020-1935

The HTTP header parsing code used an approach to end-of-line (EOL)
parsing that allowed some invalid HTTP headers to be parsed as
valid. This led to a possibility of HTTP Request Smuggling if Tomcat
was located behind a reverse proxy that incorrectly handled the
invalid Transfer-Encoding header in a particular manner. Such a
reverse proxy is considered unlikely.

CVE-2020-1938

When using the Apache JServ Protocol (AJP), care must be taken when
trusting incoming connections to Apache Tomcat. Tomcat treats AJP
connections as having higher trust than, for example, a similar HTTP
connection. If such connections are available to an attacker, they
can be exploited in ways that may be surprising. Prior to Tomcat
7.0.100, Tomcat shipped with an AJP Connector enabled by default
that listened on all configured IP addresses. It was expected (and
recommended in the security guide) that this Connector would be
disabled if not required.

Note that Debian already disabled the AJP connector by default.
Mitigation is only required if the AJP port was made accessible to
untrusted users.

For Debian 8 "Jessie", these problems have been fixed in version
7.0.56-3+really7.0.100-1.

We recommend that you upgrade your tomcat7 packages.

Further information about Debian LTS security advisories, how to apply
these updates to your system and frequently asked questions can be
found at: https://wiki.debian.org/LTS