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39 lines
2.5 KiB
Plaintext
39 lines
2.5 KiB
Plaintext
created: 20230603231547125
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creator: Octt
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modified: 20230603234352061
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modifier: Octt
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tags:
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title: SEB 3.5.0 on Linux (VM Bypass)
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Having the need of running Safe Exam Browser while I've only got GNU+Linux on my laptop and desktop, I had to look for alternative solutions.
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* There is no linux-native full SEB application, it's only for Windows and macOS.
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* Running SEB on WinPE is unfeasible as it needs to install many runtime dependencies, it's too slow to do that while booted into the live system, and on my 4 GB laptop the ramdisk is not big enough.
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* SEB by default detects and blocks virtual machines.
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** This option can be changed in the local configuration file, but when starting an exam the configuration loaded from the server takes precedence over the local one.
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** SEB 3.5.0 added an hard-to-break anti-tampering mechanism, where the LMS server verifies if the client is altered and won't let you take exams; patching the few needed modules won't work.
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Turns out only way to work around the issue is to make a relatively stealth VM.
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By analyzing the SEB for Windows source code, we can see some important files and methods:
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* [[VirtualMachineDetector.cs:IsVirtualMachine()|https://github.com/SafeExamBrowser/seb-win-refactoring/blob/11b10e8e4524c1fe65b6c3db7d12e172facf322c/SafeExamBrowser.SystemComponents/VirtualMachineDetector.cs#L49]]: Clearly the main place where VM detection is happening
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Also, by referring to various strings in the source code and [[issue #268|https://github.com/SafeExamBrowser/seb-win-refactoring/issues/268#issuecomment-994586854]], we can see that in VMs a bug occurs where 0 displays are detected. This must be accounted for after succeeding in concealing the VM from the program. A good start is in this class and method, which checks for displays and throws errors if necessary:
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* [[DisplayMonitorOperation.cs:CheckDisplayConfiguration()|https://github.com/SafeExamBrowser/seb-win-refactoring/blob/11b10e8e4524c1fe65b6c3db7d12e172facf322c/SafeExamBrowser.Runtime/Operations/DisplayMonitorOperation.cs#L51]]
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[TODO]
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!! VM Setup
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We choose VMWare Workstation 17 (latest version) as it lets a few important options be customized. First I created a VM with close-to-suggested settings (the primary ones don't matter here).
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Then I modified the network card settings [TODO]
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After this, I installed Windows 10 (a build from 2019 I have on a burned DVD always at hand). No VMWare tools have been installed.
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!! Hardening Windows
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[TODO] (https://pastebin.com/XEn7BykP)
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