One of the most notable aspects of White Rabbit’s attack is how its payload binary requires a specific command-line password to decrypt its internal configuration and proceed with its ransomware routine.
This method of hiding malicious activity is a trick that the ransomware family Egregor uses to hide malware techniques from analysis.
White Rabbit’s payload is inconspicuous at first glance, being a small file of around 100 KB with no notable strings and seemingly no activity.
The telltale sign of its malicious origin is the presence of strings for logging, but the actual behavior would not be easily observed without the correct password.
The sample analysts analyzed used the password or passphrase “KissMe,”, although other samples might use a different password. Figure 1 also shows the arguments accepted by the ransomware, which analysts surmise as standing for the following:
-p: password/passphrase
-f: file to be encrypted
-l: logfile
-t: malware’s start time
The ransomware routine itself is not complicated.
Like many modern ransomware families, White Rabbit uses double extortion and threatens its targets that their stolen data will be published or sold.
The ransomware creates a note for each file it encrypts. Each note bears the name of the encrypted file and is appended with “.scrypt.txt.” Prior to the ransomware routine, the malware also terminates several processes and services, particularly antivirus-related ones.
The malware then tries to encrypt files (if the -f argument is not given) in fixed, removable, and network drives, as well as resources.
It also tries to skip the following paths and directories to avoid crashing the system and destroying its own notes:
*.scrypt.txt
*.scrypt
c:windows*
*:sysvol*
*:netlogon*
c:filesource*
*.exe
*.dll
*desktop.ini
*:windows*
c:programdata*
*:programfiles*
*:program files (x86)*
*:program files (x64)*
*.lnk
*.iso
*.msi
*.sys
*.inf
%User Temp%*
*thumbs.db