Standoff 365

Exploiting SSTI Vulnerability in Messenger Machine on Standoff 365 Leads to RCE and Corporate Chat Access

A detailed writeup published by Positive Technologies researcher Seven11eleven demonstrates a full attack chain against the vulnerable Messenger machine on the Standoff 365 platform. The researcher began with network reconnaissance using nmap and directory fuzzing with ffuf, uncovering Swagger documentation and JWT-protected endpoints. After identifying user enumeration through the friend search feature, the team discovered a Server-Side Template Injection flaw in the friendship summary functionality powered by the Mako template engine. The SSTI was escalated to remote code execution by injecting Python expressions that leveraged the self.module.cache.util chain to call os.popen commands. With initial access obtained via reverse shell, the attacker pivoted to neighboring services including Gitness, RabbitMQ, and Redis to achieve the defined business risks of accessing developer corporate messaging and extracting the city messenger encryption key.

Researcher Achieves SSTI-Based Defacement of First Partner Bank Web Service on Standoff 365

A security researcher known as grizzzer detailed a full attack chain that resulted in defacing the authorization page of the First Partner Bank digital banking service inside the Standoff 365 online polygon. The demonstration began with a successful DNS zone transfer against the fpb.stf domain, revealing the dbo.fpb.stf host that hosted the target application. After identifying the Node.js, Express, and React stack, the researcher discovered that the receipt generation endpoint accepted an undocumented pretty parameter that was passed directly into the Pug template engine. This led to a server-side template injection vulnerability that was escalated to a Node.js reverse shell. With code execution, the attacker located and modified the translation.json localization file, replacing the welcome message with the string pwned by VON visible to all users. The write-up concludes with concrete hardening recommendations including disabling zone transfers, avoiding direct spread of req.query into templates, and restricting outbound connections.