CVE-2020-1938

NameCVE-2020-1938
DescriptionWhen 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. In Apache Tomcat 9.0.0.M1 to 9.0.0.30, 8.5.0 to 8.5.50 and 7.0.0 to 7.0.99, 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. This vulnerability report identified a mechanism that allowed: - returning arbitrary files from anywhere in the web application - processing any file in the web application as a JSP Further, if the web application allowed file upload and stored those files within the web application (or the attacker was able to control the content of the web application by some other means) then this, along with the ability to process a file as a JSP, made remote code execution possible. It is important to note that mitigation is only required if an AJP port is accessible to untrusted users. Users wishing to take a defence-in-depth approach and block the vector that permits returning arbitrary files and execution as JSP may upgrade to Apache Tomcat 9.0.31, 8.5.51 or 7.0.100 or later. A number of changes were made to the default AJP Connector configuration in 9.0.31 to harden the default configuration. It is likely that users upgrading to 9.0.31, 8.5.51 or 7.0.100 or later will need to make small changes to their configurations.
SourceCVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
ReferencesDLA-2133-1, DLA-2209-1, DSA-4673-1, DSA-4680-1
Debian Bugs952436, 952437, 952438

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
tomcat9 (PTS)buster9.0.31-1~deb10u6fixed
buster (security)9.0.31-1~deb10u12fixed
bullseye9.0.43-2~deb11u9fixed
bullseye (security)9.0.43-2~deb11u10fixed
sid, trixie, bookworm9.0.70-2fixed

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
tomcat7sourcejessie7.0.56-3+really7.0.100-1DLA-2133-1
tomcat7source(unstable)(unfixed)952436
tomcat8sourcejessie8.0.14-1+deb8u17DLA-2209-1
tomcat8sourcestretch8.5.54-0+deb9u1DSA-4673-1
tomcat8source(unstable)(unfixed)952438
tomcat9sourcebuster9.0.31-1~deb10u1DSA-4680-1
tomcat9source(unstable)9.0.31-1952437

Notes

[stretch] - tomcat7 <ignored> (No components in libservlet3.0-java binary package are affected)
AJP disabled in Debian in default configuration since 2008
fixed in upstream versions 9.0.31, 8.5.51, 7.0.100
https://www.tenable.com/blog/cve-2020-1938-ghostcat-apache-tomcat-ajp-file-readinclusion-vulnerability-cnvd-2020-10487
https://github.com/apache/tomcat/commit/0e8a50f0a5958744bea1fd6768c862e04d3b7e75 (9.0.31)
https://github.com/apache/tomcat/commit/9ac90532e9a7d239f90952edb229b07c80a9a3eb (9.0.31)
https://github.com/apache/tomcat/commit/64fa5b99442589ef0bf2a7fcd71ad2bc68b35fad (9.0.31)
https://github.com/apache/tomcat/commit/7a1406a3cd20fdd90656add6cd8f27ef8f24e957 (9.0.31)
https://github.com/apache/tomcat/commit/49ad3f954f69c6e838c8cd112ad79aa5fa8e7153 (9.0.31)
https://github.com/apache/tomcat/commit/69c56080fb3355507e1b55d014ec0ee6767a6150 (8.5.51)
https://github.com/apache/tomcat/commit/b962835f98b905286b78c414d5aaec2d0e711f75 (8.5.51)
https://github.com/apache/tomcat/commit/9be57601efb8a81e3832feb0dd60b1eb9d2b61d5 (8.5.51)
https://github.com/apache/tomcat/commit/64159aa1d7cdc2c118fcb5eac098e70129d54a19 (8.5.51)
https://github.com/apache/tomcat/commit/03c436126db6794db5277a3b3d871016fb9a3f23 (8.5.51)
https://github.com/apache/tomcat/commit/0d633e72ebc7b3c242d0081c23bba5e4dacd9b72 (7.0.100)
https://github.com/apache/tomcat/commit/40d5d93bd284033cf4a1f77f5492444f83d803e2 (7.0.100)
https://github.com/apache/tomcat/commit/b99fba5bd796d876ea536e83299603443842feba (7.0.100)
https://github.com/apache/tomcat/commit/f7180bafc74cb1250c9e9287b68a230f0e1f4645 (7.0.100)

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