Pinging All The Way

Published: 2016-12-24
Last Updated: 2016-12-24 15:55:30 UTC
by Didier Stevens (Version: 1)
5 comment(s)

A week or two ago reader Norris Carden submitted a malicious document. This document is another "sleeper": it waits a couple of minutes before downloading and executing a malicious payload.

The trick used here is to start a ping command (from VBA macros) that will take several minutes to execute: cmd.exe /C ping -n 250 > nul

This command does 250 pings to Google DNS It will take around 4 minutes and 10 seconds to execute. And after that, the VBA code downloads and executes malware.

Didier Stevens
Microsoft MVP Consumer Security

5 comment(s)


You can explain what's your command .How i can do that.It's is DDOS to google .Tks nice post.
what does the time delay buy the actor?
Same as the other sleeper I wrote a diary entry for.

Evade detection by time-limited, automatic dynamic analysis.

Which can in turn be defeated by killing the ping process.
just being able to ping or use might be a way for badguys to determine whether an endpoint is outside of a protected network (no IPS, NGFW, etc).
The VBA code does not check the result of the ping command. It just launches the command with a synchronous call: when the command terminates the VBA code continues to run. Regardless of what the result of the ping command is.

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