Pierluigi Paganini January 24, 2024

Researchers released PoC exploit code for a recently disclosed critical authentication bypass flaw in Fortra’s GoAnywhere MFT (Managed File Transfer).

Researchers with cybersecurity firm Horizon3’s Attack Team published technical details of the recently disclosed vulnerability CVE-2024-0204 impacting Fortra GoAnywhere MFT.

The security experts also published a proof-of-concept (PoC) exploit that allows the creation of new admin users on vulnerable instances exposed online.

“The advisory mentions that the endpoint /InitialAccountSetup.xhtml can be deleted and the service restarted to mitigate the issue. Looking through the application directories, we find that this endpoint is mapped to the com.linoma.ga.ui.admin.users.InitialAccountSetupForm class by inspecting the file GoAnywhere/adminroot/WEB-INF/forms-faces.xml.” reads the analysis published by Horizon3.

Yesterday, Fortra warned customers of a new authentication bypass vulnerability tracked as CVE-2024-0204 (CVSS score 9.8), impacting the GoAnywhere MFT (Managed File Transfer) product.

Fortra GoAnywhere Managed File Transfer is a comprehensive solution for secure file transfer, data encryption, and compliance management. It provides a centralized platform for managing and automating file transfers between disparate systems and applications, enabling secure and controlled data movement across an organization’s network.

An unauthorized user can exploit the flaw CVE-2024-0204 to create admin users using the administration portal of the appliance. The flaw was reported by Mohammed Eldeeb & Islam Elrfai from Spark Engineering Consultants on December 1, 2023.

Fortra initially issued private advisories to customers on December 4, recommending them of applying mitigations immediately.

The vulnerability impacts Fortra GoAnywhere MFT 6.x from 6.0.1 and Fortra GoAnywhere MFT 7.4.0 and earlier. Fortra addressed the issue with the release of GoAnywhere MFT 7.4.1.

“Upgrade to version 7.4.1 or higher.” reads the advisory published by the vendor. “The vulnerability may also be eliminated in non-container deployments by deleting the InitialAccountSetup.xhtml file in the install directory and restarting the services. For container-deployed instances, replace the file with an empty file and restart. “

Fortra is not aware of attacks in the wild exploiting this vulnerability.

Horizon3 researchers created an exploit using a path traversal issue to gain access to the vulnerable endpoint (/InitialAccountSetup.xhtml). Once reached the endpoint, they were able to start the procedure for the account creation.

“We considered the patches we observed and this logic, and without a way to pass the isAdminUserCreated check we were unsure exactly how this bypass could occur. Instead of using logic, and instead using our spidey senses, we considered if possibly there was a path normalization issue.” continues the analysis. “Classically for Tomcat based applications, there exist path traversal issues when the request contains /..;/. Trying to request the supposed vulnerable endpoint now with a request that looks like https://192.168.1.1:8001/goanywhere/images/..;/wizard/InitialAccountSetup.xhtml leads to the application now routing us to the setup page again!”

Organizations should check for any new additions to the ‘Admin users’ group in the GoAnywhere administrator portal as an indicator of compromise. Once a suspicious Admin user has been found, it is essential to analyze the log to determine its activity.

The availability of Horizon3’s PoC exploit code can trigger hacking campaigns targeting unpatched GoAnywhere MFT instances.

In February, 2023, the Clop ransomware group claimed to have stolen sensitive data from over 130 organizations by exploiting another zero-day vulnerability (CVE-2023-0669) in Fortra’s GoAnywhere Managed File Transfer secure file transfer tool.

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Pierluigi Paganini

(SecurityAffairs – hacking, Fortra)