CVE-2017-17743 UCOPIA Wireless Appliance restricted shell escape (< 5.1.11 / 5.0.19 / 4.4.20) feature image

Administrators can connect to their UCOPIA Wireless Appliance using the SSH (TCP/22) or Web SSH (TCP/222) interfaces. The system shell is restricted through the usage of rbash and clish: specific commands or flags are disallowed on purpose, therefore a malicious administrator might want to escape from this shell in order to execute arbitrary commands.

The vulnerability lies in the handling of the .bashrc file: rbash reads and executes this file before starting the restricted shell. However, the malicious admin has several techniques to write arbitrary contents to this file.


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