The ransomware attempts to terminate any process that may interfere with encryption.
Interestingly, the kph.sys driver from Process Hacker come into play in process termination in some cases but not others.
This likely reflects the attacker’s need to leverage the driver to disable certain local security solutions on specific engagements.
There are numerous process names, service names and folder names included in each sample’s configuration.
For example, in sample 19CE538B2597DA454ABF835CFF676C28B8EB66F7, the following processes, services and folders are excluded from the encryption process:
Processes names skipped:
sql.exe
oracle.exe
ocssd.exe
dbsnmp.exe
visio.exe
winword.exe
wordpad.exe
notepad.exe
excel.exe
onenote.exe
outlook.exe
synctime.exe
agntsvc.exe
isqlplussvc.exe
xfssvccon.exe
mydesktopservice.exe
ocautoupds.exe
encsvc.exe
firefox.exe
tbirdconfig.exe
mydesktopqos.exe
ocomm.exe
dbeng50.exe
sqbcoreservice.exe
infopath.exe
msaccess.exe
mspub.exe
powerpnt.exe
steam.exe
thebat.exe
thunderbird.exe
Service names terminated:
memtas
mepocs
veeam
backup
GxVss
GxBlr
GxFWD
GxCVD
GxCIMgr
DefWatch
ccEvtMgr
ccSetMgr
SavRoam
RTVscan
QBFCService
QBIDPService
Intuit.QuickBooks.FCS
QBCFMonitorService
AcrSch2Svc
AcronisAgent
CASAD2DWebSvc
CAARCUpdateSvc
Folders names skipped:
Program Files
Program Files (x86)
AppData
Windows
Windows.old
Tor Browser
Internet Explorer
Google
Opera
Opera Software
Mozilla
File names skipped:
autorun.inf
boot.ini
bootfont.bin
bootsect.bak
bootmgr
bootmgr.efi
bootmgfw.efi
desktop.ini
iconcache.db
ntldr
ntuser.dat
ntuser.dat.log
ntuser.ini
thumbs.db
As with most modern ransomware families, Rook will also attempt to delete volume shadow copies to prevent victims from restoring from backup. This is achieved via vssadmin.exe.