Apache Tomcat up to 7.0.99/8.5.50/9.0.30 AJP Connector Ghostcat input validation

Summaryinfo

A vulnerability marked as critical has been reported in Apache Tomcat up to 7.0.99/8.5.50/9.0.30. Impacted is an unknown function of the component AJP Connector. Performing a manipulation results in input validation (Ghostcat). This vulnerability is identified as CVE-2020-1938. The attack can be initiated remotely. Additionally, an exploit exists. It is suggested to install a patch to address this issue.

Detailsinfo

A vulnerability was found in Apache Tomcat up to 7.0.99/8.5.50/9.0.30 (Application Server Software). It has been classified as critical. This affects an unknown code of the component AJP Connector. The manipulation with an unknown input leads to a input validation vulnerability (Ghostcat). CWE is classifying the issue as CWE-20. The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

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.

The weakness was released 02/20/2020 as CNVD-2020-10487 as confirmed tweet (Twitter). The advisory is shared at twitter.com. The public release was coordinated with Apache. This vulnerability is uniquely identified as CVE-2020-1938. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. Technical details are unknown but a public exploit is available.

A public exploit has been developed in Python and been published immediately after the advisory. The exploit is shared for download at github.com. It is declared as attacked. The vulnerability was handled as a non-public zero-day exploit for at least 48 days. During that time the estimated underground price was around $5k-$25k. The vulnerability scanner Nessus provides a plugin with the ID 212407 (Oracle Siebel Server (July 2020 CPU)), which helps to determine the existence of the flaw in a target environment. The CISA Known Exploited Vulnerabilities Catalog lists this issue since 03/03/2022 with a due date of 03/17/2022:

Apply updates per vendor instructions.

Upgrading to version 7.0.100, 8.5.51 or 9.0.31 eliminates this vulnerability. Applying a patch is able to eliminate this problem. The best possible mitigation is suggested to be patching the affected component.

The vulnerability is also documented in the databases at Exploit-DB (48143), Tenable (212407) and EUVD (EUVD-2020-0481). Further details are available at tenable.com. Entries connected to this vulnerability are available at VDB-158110, VDB-158112, VDB-158326 and VDB-158327. Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Type

• Application Server Software

Vendor

• Apache

Name

• Tomcat

Version

• 7.0.0
• 7.0.1
• 7.0.2
• 7.0.3
• 7.0.4
• 7.0.5
• 7.0.6
• 7.0.7
• 7.0.8
• 7.0.9
• 7.0.10
• 7.0.11
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• 7.0.13
• 7.0.14
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• 7.0.17
• 7.0.18
• 7.0.19
• 7.0.20
• 7.0.21
• 7.0.22
• 7.0.23
• 7.0.24
• 7.0.25
• 7.0.26
• 7.0.27
• 7.0.28
• 7.0.29
• 7.0.30
• 7.0.31
• 7.0.32
• 7.0.33
• 7.0.34
• 7.0.35
• 7.0.36
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• 7.0.39
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• 7.0.41
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• 7.0.45
• 7.0.46
• 7.0.47
• 7.0.48
• 7.0.49
• 7.0.50
• 7.0.51
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• 7.0.69
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• 7.0.91
• 7.0.92
• 7.0.93
• 7.0.94
• 7.0.95
• 7.0.96
• 7.0.97
• 7.0.98
• 7.0.99
• 8.5.0
• 8.5.1
• 8.5.2
• 8.5.3
• 8.5.4
• 8.5.5
• 8.5.6
• 8.5.7
• 8.5.8
• 8.5.9
• 8.5.10
• 8.5.11
• 8.5.12
• 8.5.13
• 8.5.14
• 8.5.15
• 8.5.16
• 8.5.17
• 8.5.18
• 8.5.19
• 8.5.20
• 8.5.21
• 8.5.22
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• 8.5.24
• 8.5.25
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• 8.5.27
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• 8.5.30
• 8.5.31
• 8.5.32
• 8.5.33
• 8.5.34
• 8.5.35
• 8.5.36
• 8.5.37
• 8.5.38
• 8.5.39
• 8.5.40
• 8.5.41
• 8.5.42
• 8.5.43
• 8.5.44
• 8.5.45
• 8.5.46
• 8.5.47
• 8.5.48
• 8.5.49
• 8.5.50
• 9.0.0
• 9.0.1
• 9.0.2
• 9.0.3
• 9.0.4
• 9.0.5
• 9.0.6
• 9.0.7
• 9.0.8
• 9.0.9
• 9.0.10
• 9.0.11
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• 9.0.20
• 9.0.21
• 9.0.22
• 9.0.23
• 9.0.24
• 9.0.25
• 9.0.26
• 9.0.27
• 9.0.28
• 9.0.29
• 9.0.30

License

• open-source

Website

• Vendor: https://www.apache.org/

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Entryinfo

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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