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Yesterday I installed version 0.43 of 'chkrootkit', and when I run it for the first time I got this output:
You have 1 process hidden for readdir comman
You have 1 process hidden for ps command
Warning: Possible LKM Trojan installed
However, all subsequent runs of 'chkrootkit' -done immediately after and from then on at several intervals- didn't show that warning anymore. I also compiled another instance of the program in other directory and it didn't find anything ("Checking `lkm'... nothing detected").
After that, I verified some system binaries ('ps', 'ls' and many others) with rpm -V and the output showed that they hadn't changed (at least according to 'rpm').
Then I compared the file 'System.map' with the kernel syscall table by means of the program 'kern_check', and no inconsistencies were found.
Googling around I also found references stating that LKM detection on 'chkrootkit 0.43' is sometimes prone to false positives, and even the FAQ of the program indicates that some processes could report false detections in some cases.
In view of all this, can I assume that this has been a false positive, or is there room for suspicion?