Threat description




Trojan-Dropper:OSX/Revir.A drops a downloader component that downloads a backdoor program onto the system, while camouflaging its activity by opening a PDF file to distract the user.


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Technical Details

Trojan-Dropper:OSX/Revir.A drops a PDF file in the /tmp folder, then opens it to distract the user from noticing any other activity occuring:

Screenshot of a PDF file dropped by Trojan-Dropper:OSX/Revir.A.

The PDF file contains Chinese-language text related to political issues, which some users may find offensive.

Note that the PDF file in the screenshot above uses the name 'trojan.pdf'. The PDF file will actually use the same name as the trojan-dropper's binary file, which is usually saved to the /Users/%user%/Downloads or /User/%user%/Documents folders.


In the background, the malware will drop and execute the following downloader component (detected as Trojan-Downloader:OSX/Revir.A):

  • /tmp/host

This file downloads and executes a file from the following remote location:

  • h t t p://[...]

The downloaded file is also saved as:

  • /tmp/updtdata

As of this writing, the downloaded file is detected as Backdoor:OSX/Imuler.A. Our Browsing Protection blocks the download server hosting the file.

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