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How to find which process used a port? Possible Trojan.

I got this warning on my router:


Threat

A Network Trojan was Detected. Signature ET MALWARE

Suspicious User Agent (Autoupdate). From: 10.0.1.3:61379, to: 54.36.160.184:80, protocol: TCP


I did "% lsof -i" to try to figure out which process it was, but none was using that port when I checked. Is there any way to monitor the port and catch which process tries to use it, the next time it does?

Mac Pro, macOS 10.13

Posted on Oct 4, 2020 4:27 AM

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Question marked as Best reply

Posted on Oct 4, 2020 7:03 AM

Works here...

im19:~ bd1$ lsof -nP -i4TCP:$61379 | grep LISTEN

im19:~ bd1$ 


bash -c 'while [ 0 ]; do lsof -nP -i4TCP:$61379 | grep LISTEN;sleep 1;done'

Or...

bash -c 'while [ 0 ]; do sudo lsof -iTCP -sTCP:LISTEN -n -P;sleep 5;done'


Control+c to stop

5 replies

Oct 4, 2020 6:48 AM in response to BDAqua

% lsof -nP -i4TCP:$63681 | grep LISTEN

lsof: unacceptable port specification in: -i 4TCP:

lsof 4.89

latest revision: ftp://lsof.itap.purdue.edu/pub/tools/unix/lsof/

latest FAQ: ftp://lsof.itap.purdue.edu/pub/tools/unix/lsof/FAQ

latest man page: ftp://lsof.itap.purdue.edu/pub/tools/unix/lsof/lsof_man

usage: [-?abhlnNoOPRtUvV] [+|-c c] [+|-d s] [+D D] [+|-f[cgG]]

[-F [f]] [-g [s]] [-i [i]] [+|-L [l]] [+|-M] [-o [o]] [-p s]

[+|-r [t]] [-s [p:s]] [-S [t]] [-T [t]] [-u s] [+|-w] [-x [fl]] [--] [names]

Use the ``-h'' option to get more help information.


% sudo lsof -iTCP -sTCP:LISTEN -n -P


shows about 25 lines of things on various ports, but 1) my port of interest isn't there - is there an option to have it wait and keep testing until it shows up, or I need to write a script for that, and 2) I would assume there are more than 25 processes making connections right now - what are the criteria for being shown on this list? Thanks!!

How to find which process used a port? Possible Trojan.

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