Moderate
CVE-2020-1938
CVE-2020-1938
Description
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. 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.
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Technical Analysis
Current PoC’s offer unauthenticated LFI inside the webroot.
Depending on the application and organisations configuration this could reveal sensitive information from database config or other configurations within the source code.
There is the potential for RFI / RCE although example of this are not yet public.
With a shift towards containers like Kubernetes / Docker it is important to note that older tags which may be version pinned by organisations are unlikely to be patched.
The official containers distributed by Apache include tags for vulnerable version although they do not appear to server port 8009 by default. A custom server.xml is required. This is “Likely” to happen.
Technical Analysis
after having spent some time trying to traverse webroot, i feel like saying that it’s “unlikely” that ajp will let you read file through the filesystem, because of how tomcat segregates the environment.
i’d love being proven wrong.
having file upload on the docroot, as other said, it’s possible to achieve RCE quite easily.
(un)fortunately, the file can be anything, even a valid image with the classic code-append like we all did in php. given this behaviour, it’s trivial to bypass upload filters.
Technical Analysis
We’re still trying to find a way to get generic RCE out of this, but it’s not promising: https://twitter.com/steventseeley/status/1230871514343518208. For now, it seems to be limited to LFI in the web root.
I did manage to get a shell, but it was rather contrived, since I uploaded the text file containing JSP myself, then included it. It at least did not require a .jsp extension, but the extension was required in the request URI.
Technical Analysis
The only file you can rely on for detection is /WEB-INF/web.xml, but to read something else you’ll have to know the directory structure which is unlikely when you audit a client infrastructure. To achieve RCE you’ll be required to get file upload which is also less likely. In many cases in real life it may end not useful outside proving the vulnerability exists.
There are still some chances you can read /RELEASE-NOTES.txtif you don’t have another mean to know the version used.
If the application is deployed under an unguessable path it’s likely you won’t be able to go further but if you can reach to the app and browse it’ll may be able to understand paths and try to read the source code of the application.
CVSS V3 Severity and Metrics
General Information
Vendors
- apache,
- blackberry,
- debian,
- fedoraproject,
- netapp,
- opensuse,
- oracle
Products
- agile engineering data management 6.2.1.0,
- agile plm 9.3.3,
- agile plm 9.3.5,
- agile plm 9.3.6,
- communications element manager 8.1.1,
- communications element manager 8.2.0,
- communications element manager 8.2.1,
- communications instant messaging server 10.0.1.4.0,
- data availability services -,
- debian linux 10.0,
- debian linux 8.0,
- debian linux 9.0,
- fedora 30,
- fedora 31,
- fedora 32,
- geode 1.12.0,
- good control,
- health sciences empirica inspections 1.0.1.2,
- health sciences empirica signal 7.3.3,
- hospitality guest access 4.2.0,
- hospitality guest access 4.2.1,
- instantis enterprisetrack,
- leap 15.1,
- mysql enterprise monitor,
- oncommand system manager,
- siebel ui framework,
- tomcat,
- transportation management 6.3.7,
- workload manager 12.2.0.1,
- workload manager 18c,
- workload manager 19c,
- workspaces server 7.0.1,
- workspaces server 7.1.2,
- workspaces server 8.1.0,
- workspaces server 9.0
Metasploit Modules
References
Advisory
