Description
Win32.Reckmess.A consists of a trojan downloader (Reckmess.A!downloader) and subsequently the backdoor trojan it downloads(Win32.Reckmess.A). The downloader is a Win32 executable with a length of 3,114 bytes, while the backdoor component has been distributed as a 48,887-byte, PECompact-packed Win32 executable. Note: The file size of the backdoor component may vary across very similar, minor variants of this trojan.
Back to top
Method of Infection
Reckmess.A!downloader has been distributed as "bla.exe" (in one confirmed case this file was dropped via an unpatched Internet Explorer exploit). When executed, it downloads a file from an encrypted URL in its code and executes it using the name "c:\winamp.exe". The file "C:\bla.exe" is then deleted.
When the backdoor trojan is executed, it copies itself to %System%\<random file name>.exe and sets the following registry key so as to run each time Windows is started:
HKCU\SOFTWARE\Microsoft\Windows\CurrentVersion\Run\JavaUpdate0.07 = "%System%\<random file name>.exe"
The backdoor trojan, running as “c:\winampa.exe”, deletes itself and remains running in memory.
Note: ‘%System%’ is a variable location. The trojan determines the location of the current System folder by querying the operating system. The default installation location for the System directory for Windows 2000 and NT is C:\Winnt\System32; for 95, 98 and ME is C:\Windows\System; and for XP is C:\Windows\System32.
Back to top
Payload
Backdoor Functionality
The backdoor component opens a random port on the affected machine and listens for incoming commands. This allows an attacker to take control of the affected machine - eg to instruct the trojan to download and execute files. Files are downloaded to the %System% directory with a random file name and an .exe extension.
Terminates Processes
The trojan checks if the following processes are running and if so, terminates them:
ACKWIN32.EXE
ANTI-TROJAN.EXE
APVXDWIN.EXE
AUTODOWN.EXE
AVCONSOL.EXE
AVE32.EXE
AVGCTRL.EXE
AVKSERV.EXE
AVNT.EXE
AVP32.EXE
AVPCC.EXE
AVPDOS32.EXE
AVPM.EXE
AVPTC32.EXE
AVPUPD.EXE
AVSCHED32.EXE
AVWIN95.EXE
AVWUPD32.EXE
BLACKD.EXE
BLACKICE.EXE
CFIADMIN.EXE
CFIAUDIT.EXE
CFINET.EXE
CFINET32.EXE
CLAW95.EXE
CLAW95CF.EXE
CLEANER.EXE
CLEANER3.EXE
DVP95
DVP95.EXE
ECENGINE.EXE
ESAFE.EXE
ESPWATCH.EXE
F-AGNT95.EXE
F-PROT.EXE
F-PROT95.EXE
F-STOPW.EXE
FINDVIRU.EXE
FP-WIN.EXE
FPROT.EXE
FRW.EXE
IAMAPP.EXE
IAMSERV.EXE
IBMASN.EXE
IBMAVSP.EXE
ICLOAD95.EXE
ICLOADNT.EXE
ICMON.EXE
ICSUPP95.EXE
ICSUPPNT.EXE
IFACE.EXE
IOMON98.EXE
JEDI.EXE
LOCKDOWN2000.EXE
LUALL.EXE
MOOLIVE.EXE
MPFTRAY.EXE
N32SCANW.EXE
NAVAPW32.EXE
NAVLU32.EXE
NAVNT.EXE
NAVW32.EXE
NAVWNT.EXE
NISUM.EXE
NMAIN.EXE
NORMIST.EXE
NUPGRADE.EXE
NVC95.EXE
OUTPOST.EXE
PADMIN.EXE
PAVCL.EXE
PAVSCHED.EXE
PAVW.EXE
PCCWIN98.EXE
PCFWALLICON.EXE
PERSFW.EXE
RAV7.EXE
RAV7WIN.EXE
RESCUE.EXE
SAFEWEB.EXE
SCAN32.EXE
SCAN95.EXE
SCANPM.EXE
SCRSCAN.EXE
SERV95.EXE
SMC.EXE
SPHINX.EXE
SWEEP95.EXE
TBSCAN.EXE
TCA.EXE
TDS2-98.EXE
TDS2-NT.EXE
VET95.EXE
VETTRAY.EXE
VSCAN40.EXE
VSECOMR.EXE
VSHWIN32.EXE
VSSTAT.EXE
WEBSCANX.EXE
WFINDV32.EXE
ZONEALARM.EXE
_AVPCC.EXE
_AVPM.EXE
ccapp.exe
smc.exe
zlclient.exe
Back to top