Analysis by: Jennifer Gumban
ALIASES:

Worm:Win32/Nuqel.Z (Microsoft), Virus.Win32.Sality.gen (Kaspersky)

 PLATFORM:

Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:
 INFORMATION EXPOSURE:

  • Threat Type: File infector

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel: Downloaded from the Internet, Dropped by other malware, Propagates via flashdrives

This file infector arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It uses the default Windows folder icon to trick users into opening the file. Double-clicking the file executes this malware.

It adds certain registry entries to disable the Task Manager. This action prevents users from terminating the malware process, which can usually be done via the Task Manager.

It drops copies of itself into all the removable drives connected to an affected system.

It modifies the Internet Explorer Zone Settings.

  TECHNICAL DETAILS

File Size: Varies
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 05 Aug 2013
Payload: Connects to URLs/IPs, Drops files

Arrival Details

This file infector arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

Installation

This file infector uses the default Windows folder icon to trick users into opening the file. Double-clicking the file executes this malware.

It adds the following mutexes to ensure that only one of its copies runs at any one time:

  • Op1mutx9
  • {Process Name}M_{Random Number}_ - Mutex is terminated immediately

Autostart Technique

This file infector adds the following registry entries to enable its automatic execution at every system startup:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
{Chosen Program} = "{Path of Infected File}"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
{Chosen Program} = "{Path of Infected File}"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon
Shell = "Explorer.exe {Infected File}.exe"

It adds the following entries or lines to the SYSTEM.INI file to enable its automatic execution at every system startup:

  • [Autorun]
  • Open={Infected File}.exe
  • Shellexecute={Infected File}.exe
  • Shell\Open\command={Infected File}.exe
  • Shell=Open

Other System Modifications

This file infector adds the following line(s)/entry(ies) in the SYSTEM.INI file:

  • [MCIDRV_VER]
  • DEVICEMB={Random Numbers}

It adds the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
WorkgroupCrawler\Shares
shared = "{Path of Malware Copy}"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Explorer
NofolderOptions = "0"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\policies\
system
EnableLUA = "0"

HKEY_LOCAL_MACHINE\SYSTEM\{Current Control Set}\
Services\Schedule
AtTaskMaxHours = "0"

It adds the following registry entries as part of its installation routine:

HKEY_CURRENT_USER\Software\{Username}914
{%1st Letter of Username%}{Num}_{Num} = "{DWORD}"

HKEY_CURRENT_USER\Software\{Username}914\
{Random Numbers}
{Random Numbers} = {Random Characters}

It adds the following registry entries to disable the Task Manager:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
System
DisableRegistryTools = "1"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
System
DisableTaskMgr = "0"

It creates the following registry entry(ies) to bypass Windows Firewall:

HKEY_LOCAL_MACHINE\SYSTEM\{Current Control Set}\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\AuthorizedApplications\
List
{Original Malware File Path} = "{Original Malware File Path}:*:Enabled:ipsec"

File Infection

This file infector infects the following file types:

  • .EXE
  • .SCR

Propagation

This file infector drops copies of itself into all the removable drives connected to an affected system.

Process Termination

This file infector terminates processes or services that contain any of the following strings if found running in the affected system's memory:

  • _AVPM.
  • A2GUARD.
  • AAVSHIELD.
  • ADVCHK.
  • AHNSD.
  • AIRDEFENSE
  • ALERTSVC
  • ALMON.
  • ALOGSERV
  • ALSVC.
  • AMON.
  • ANTI-TROJAN.
  • ANTIVIR
  • ANTS.
  • APVXDWIN.
  • ARMOR2NET.
  • ASHAVAST.
  • ASHDISP.
  • ASHENHCD.
  • ASHMAISV.
  • ASHPOPWZ.
  • ASHSERV.
  • ASHSIMPL.
  • ASHSKPCK.
  • ASHWEBSV.
  • ASWUPDSV.
  • ATCON.
  • ATUPDATER.
  • ATWATCH.
  • AUPDATE.
  • AUTODOWN.
  • AUTOTRACE.
  • AUTOUPDATE.
  • AVAST
  • AVAST
  • AVAST
  • AVCIMAN.
  • AVCONSOL.
  • AVENGINE.
  • AVGAMSVR.
  • AVGCC.
  • AVGCC32.
  • AVGCTRL.
  • AVGEMC.
  • AVGFWSRV.
  • AVGNT.
  • AVGNTDD
  • AVGNTMGR
  • AVGSERV.
  • AVGUARD.
  • AVGUPSVC.
  • AVINITNT.
  • AVKSERV.
  • AVKSERVICE.
  • AVKWCTL.
  • AVP32.
  • AVPCC.
  • AVPM.
  • AVSCHED32.
  • AVSYNMGR.
  • AVWUPD32.
  • AVWUPSRV.
  • AVXMONITOR9X.
  • AVXMONITORNT.
  • AVXQUAR.
  • BACKWEB-4476822.
  • BDMCON.
  • BDNEWS.
  • BDOESRV.
  • BDSS.
  • BDSUBMIT.
  • BDSWITCH.
  • BLACKD.
  • BLACKICE.
  • CAFIX.
  • CCAPP.
  • CCEVTMGR.
  • CCPROXY.
  • CCSETMGR.
  • CFIAUDIT.
  • CLAMTRAY.
  • CLAMWIN.
  • CLAW95.
  • CLAW95CF.
  • CLEANER.
  • CLEANER3.
  • CLISVC.
  • CMGRDIAN.
  • CUREIT
  • CUREIT.
  • DEFWATCH.
  • DOORS.
  • DRVIRUS.
  • DRWADINS.
  • DRWEB32W.
  • DRWEBSCD.
  • DRWEBUPW.
  • ESCANH95.
  • ESCANHNT.
  • EWIDOCTRL.
  • EZANTIVIRUSREGISTRATIONCHECK.
  • F-AGNT95.
  • F-PROT95.
  • F-SCHED.
  • F-STOPW.
  • FAMEH32.
  • FAST.
  • FCH32.
  • FILEMON
  • FIRESVC.
  • FIRETRAY.
  • FIREWALL.
  • FPAVUPDM.
  • FRESHCLAM.
  • FSAV32.
  • FSAVGUI.
  • FSBWSYS.
  • FSDFWD.
  • FSGK32.
  • FSGK32ST.
  • FSGUIEXE.
  • FSM32.
  • FSMA32.
  • FSMB32.
  • FSPEX.
  • FSSM32.
  • GCASDTSERV.
  • GCASSERV.
  • GIANTANTISPYWAREMAIN.
  • GIANTANTISPYWAREUPDATER.
  • GUARDGUI.
  • GUARDNT.
  • HREGMON.
  • HRRES.
  • HSOCKPE.
  • HUPDATE.
  • IAMAPP.
  • IAMSERV.
  • ICLOAD95.
  • ICLOADNT.
  • ICMON.
  • ICSSUPPNT.
  • ICSUPP95.
  • ICSUPPNT.
  • IFACE.
  • INETUPD.
  • INOCIT.
  • INORPC.
  • INORT.
  • INOTASK.
  • INOUPTNG.
  • IOMON98.
  • ISAFE.
  • ISATRAY.
  • ISRV95.
  • ISSVC.
  • KAVMM.
  • KAVPF.
  • KAVPFW.
  • KAVSTART.
  • KAVSVC.
  • KAVSVCUI.
  • KMAILMON.
  • KPFWSVC.
  • KWATCH.
  • LOCKDOWN2000.
  • LOGWATNT.
  • LUALL.
  • LUCOMSERVER.
  • LUUPDATE.
  • MCAGENT.
  • MCMNHDLR.
  • MCREGWIZ.
  • MCUPDATE.
  • MCVSSHLD.
  • MINILOG.
  • MYAGTSVC.
  • MYAGTTRY.
  • NAVAPSVC.
  • NAVAPW32.
  • NAVLU32.
  • NAVW32.
  • NEOWATCHLOG.
  • NEOWATCHTRAY.
  • NISSERV
  • NISUM.
  • NMAIN.
  • NOD32
  • NOD32.
  • NORMIST.
  • NOTSTART.
  • NPAVTRAY.
  • NPFMNTOR.
  • NPFMSG.
  • NPROTECT.
  • NSCHED32.
  • NSMDTR.
  • NSSSERV.
  • NSSTRAY.
  • NTRTSCAN.
  • NTXCONFIG.
  • NUPGRADE.
  • NVC95.
  • NVCOD.
  • NVCTE.
  • NVCUT.
  • NWSERVICE.
  • OFCPFWSVC.
  • OUTPOST.
  • PAVFIRES.
  • PAVFNSVR.
  • PAVKRE.
  • PAVPROT.
  • PAVPROXY.
  • PAVPRSRV.
  • PAVSRV51.
  • PAVSS.
  • PCCGUIDE.
  • PCCIOMON.
  • PCCNTMON.
  • PCCPFW.
  • PCCTLCOM.
  • PCTAV.
  • PERSFW.
  • PERTSK.
  • PERVAC.
  • PNMSRV.
  • POP3TRAP.
  • POPROXY.
  • PREVSRV.
  • PSIMSVC.
  • QHM32.
  • QHONLINE.
  • QHONSVC.
  • QHPF.
  • QHWSCSVC.
  • RAVMON.
  • RAVTIMER.
  • REALMON.
  • REALMON95.
  • RFWMAIN.
  • RTVSCAN.
  • RTVSCN95.
  • RULAUNCH.
  • SAVADMINSERVICE.
  • SAVMAIN.
  • SAVPROGRESS.
  • SAVSCAN.
  • SCAN32.
  • SCANNINGPROCESS.
  • SDHELP.
  • SHSTAT.
  • SITECLI.
  • SPBBCSVC.
  • SPHINX.
  • SPIDERML.
  • SPIDERNT.
  • SPIDERUI.
  • SPYBOTSD.
  • SPYXX.
  • SS3EDIT.
  • STOPSIGNAV.
  • SWAGENT.
  • SWDOCTOR.
  • SWNETSUP.
  • SYMLCSVC.
  • SYMPROXYSVC.
  • SYMSPORT.
  • SYMWSC.
  • SYNMGR.
  • TAUMON.
  • TBMON.
  • TDS-3.
  • TEATIMER.
  • TFAK.
  • THAV.
  • THSM.
  • TMAS.
  • TMLISTEN.
  • TMNTSRV.
  • TMPFW.
  • TMPROXY.
  • TNBUTIL.
  • TRJSCAN.
  • UP2DATE.
  • VBA32ECM.
  • VBA32IFS.
  • VBA32LDR.
  • VBA32PP3.
  • VBSNTW.
  • VCHK.
  • VCRMON.
  • VETTRAY.
  • VIRUSKEEPER.
  • VPTRAY.
  • VRFWSVC.
  • VRMONNT.
  • VRMONSVC.
  • VRRW32.
  • VSECOMR.
  • VSHWIN32.
  • VSMON.
  • VSSERV.
  • VSSTAT.
  • WATCHDOG.
  • WEBPROXY.
  • WEBSCANX.
  • WEBTRAP.
  • WGFE95.
  • WINAW32.
  • WINROUTE.
  • WINSS.
  • WINSSNOTIFY.
  • WRADMIN.
  • WRCTRL.
  • XCOMMSVR.
  • ZATUTOR.
  • ZAUINST.
  • ZLCLIENT.
  • ZONEALARM.

Web Browser Home Page and Search Page Modification

This file infector modifies the Internet Explorer Zone Settings.

Download Routine

This file infector connects to the following URL(s) to download its component file(s):

  • http://{BLOCKED}.67.154/testo5/
  • http://{BLOCKED}nfo.co.kr/picassa.dat
  • http://{BLOCKED}ustnet777.info/home.gif
  • http://{BLOCKED}ustnet777.info/home.gif
  • http://{BLOCKED}ustnet987.info/home.gif
  • http://{BLOCKED}ustnet888.info/home.gif

Other Details

This file infector attempts to access the following websites to download files, which are possibly malicious:

  • http://www.{BLOCKED}fqwieluoi.info/
  • http://{BLOCKED}7638dfqwieuoi.info/
  • http://{BLOCKED}.{BLOCKED}.ua/mainh.gif
  • http://{BLOCKED}nia.{BLOCKED}1.ru/mainh.gif
  • http://{BLOCKED}x.ru/logos.gif
  • http://{BLOCKED}o.com/logos.gif
  • http://{BLOCKED}gital.com/dumper/backup/fmain.gif
  • http://{BLOCKED}vcfds677.info
  • http://{BLOCKED}egood24.com
  • http://{BLOCKED}ctchoice1.com
  • http://{BLOCKED}ddt.net
  • http://{BLOCKED}ash.net
  • http://{BLOCKED}ash.net
  • http://{BLOCKED}-frn.net
  • http://{BLOCKED}ash.net
  • http://{BLOCKED}cash.net
  • http://{BLOCKED}kewo7i487fksd.info
  • http://{BLOCKED}96.info

NOTES:

It drops a rootkit component as %System%\drivers\{Random Name}.sys and registers it as a service by creating the following registry key/entry:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\{Random Name}
ImagePath=%System%\drivers\{Random Name}.sys

It then deletes this dropped component.

It saves the downloaded files in the folder, %User Temp%, and executes it. This file infector deletes files with the following extensions:

  • .AVC
  • .VDB

It also deletes the following services:

  • aswUpdSv
  • avast! Antivirus
  • avast! Mail Scanner
  • avast! Web Scanner
  • BackWeb Plug-in - 4476822
  • BGLiveSvc
  • BlackICE
  • CAISafe
  • ccEvtMgr
  • ccProxy
  • ccSetMgr
  • F-Prot Antivirus Update Monitor
  • fsbwsys
  • FSDFWD
  • F-Secure Gatekeeper Handler Starter
  • fshttps
  • InoRPC
  • InoRT
  • InoTask
  • ISSVC
  • LavasoftFirewall
  • LIVESRV
  • McAfeeFramework
  • McShield
  • McTaskManager
  • navapsvc
  • NOD32krn
  • NPFMntor
  • NSCService
  • Outpost Firewall main module
  • OutpostFirewall
  • PAVFIRES
  • PAVFNSVR
  • PavProt
  • PavPrSrv
  • PAVSRV
  • PcCtlCom
  • PersonalFirewal
  • PREVSRV
  • ProtoPort Firewall service
  • PSIMSVC
  • RapApp
  • SmcService
  • SNDSrvc
  • SPBBCSvc
  • Symantec Core LC
  • Tmntsrv
  • TmPfw
  • tmproxy
  • UmxAgent
  • UmxCfg
  • UmxLU
  • UmxPol
  • vsmon
  • VSSERV
  • WebrootDesktopFirewallDataService
  • WebrootFirewall
  • XCOMM

This file infector deletes entries from the following registry keys:

  • HKEY_CURRENT_USER\System\CurrentControlSet\Control\SafeBoot
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ProfileList
  • HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Ext\Stats
  • HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Ext\Stats
  • HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Browser
  • Helper Objects

  SOLUTION

Minimum Scan Engine: 9.300
FIRST VSAPI PATTERN FILE: 10.214.07
FIRST VSAPI PATTERN DATE: 13 Aug 2013
VSAPI OPR PATTERN File: 10.215.00
VSAPI OPR PATTERN Date: 14 Aug 2013

Step 1

Before doing any scans, Windows XP, Windows Vista, and Windows 7 users must disable System Restore to allow full scanning of their computers.

Step 2

Identify and terminate files detected as PE_SALITY.EK-O

[ Learn More ]
  1. Windows Task Manager may not display all running processes. In this case, please use a third-party process viewer, preferably Process Explorer, to terminate the malware/grayware/spyware file. You may download the said tool here.
  2. If the detected file is displayed in either Windows Task Manager or Process Explorer but you cannot delete it, restart your computer in safe mode. To do this, refer to this link for the complete steps.
  3. If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.

Step 3

Delete this registry value

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.

 
  • In HKEY_CURRENT_USER\Software\{Username}914
    • {%1st Letter of Username%}{Num}_{Num} = "{DWORD}"
  • In HKEY_CURRENT_USER\Software\{Username}914\{Random Numbers}
    • {Random Numbers} = {Random Characters}
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\System
    • DisableRegistryTools = "1"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\System
    • DisableTaskMgr = "0"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • {Chosen Program} = "{Path of Infected File}"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • {Chosen Program} = "{Path of Infected File}"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
    • Shell = "Explorer.exe {Infected File}.exe"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\WorkgroupCrawler\Shares
    • shared = "{Path of Malware Copy}"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer
    • NofolderOptions = "0"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\policies\system
    • EnableLUA = "0"
  • In HKEY_LOCAL_MACHINE\SYSTEM\{Current Control Set}\Services\Schedule
    • AtTaskMaxHours = "0"

Step 4

Remove the following string/s that this malware/grayware added to these system configuration files

[ Learn More ]
[MCIDRV_VER] DEVICEMB={Random Numbers}

Step 5

Remove the following string/s that this malware/grayware added to these system configuration files

[ Learn More ]

[Autorun] Open={Infected File}.exe Shellexecute={Infected File}.exe Shell\Open\command={Infected File}.exe Shell=Open

Step 6

Reset Internet security settings

[ Learn More ]

Step 7

Scan your computer with your Trend Micro product to clean files detected as PE_SALITY.EK-O. If the detected files have already been cleaned, deleted, or quarantined by your Trend Micro product, no further step is required. You may opt to simply delete the quarantined files. Please check this Knowledge Base page for more information.

Step 8

Restore these deleted registry keys/values from backup

*Note: Only Microsoft-related keys/values will be restored. If the malware/grayware also deleted registry keys/values related to programs that are not from Microsoft, please reinstall those programs on your computer.


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