Worm.Win32.Dorkbot_81f1f333bf

by malwarelabrobot on September 2nd, 2013 in Malware Descriptions.

Trojan.Win32.Patched.dj (Kaspersky), Virus.Win32.Slugin.a (v) (VIPRE), Virus.Win32.Slugin!IK (Emsisoft), Backdoor.Win32.Farfli.FD, Worm.Win32.Dorkbot.FD, GenericUSBInfector.YR, GenericProxy.YR, GenericSYNFlooder.YR, GenericUDPFlooder.YR, GenericDNSBlocker.YR, GenericMSNWorm.YR, GenericIRCBot.YR, GenericAutorunWorm.YR, WormDorkbot.YR, GenericPhysicalDrive0.YR, GenericInjector.YR, BankerGeneric.YR (Lavasoft MAS)
Behaviour: Banker, Trojan, Backdoor, Flooder, Worm, Virus, WormAutorun, IRCBot, MSNWorm, DNSBlocker, UDPFlooder, SYNFlooder, Trojan-Proxy, USBInfector


The description has been automatically generated by Lavasoft Malware Analysis System and it may contain incomplete or inaccurate information.

Summary
Technical Details
Removal Recommendations

MD5: 81f1f333bf0985c0daf0aee13a2b1cdf
SHA1: 8c1cbbd49336e86edbc662535995fec4230edc33
SHA256: b57ba34360077a86fce83b2ef5c95ee5096402266581ee23ae352c68441b7006
SSDeep: 3072:m05Vrs2uoJohxNO2HF9qXxduDfrKRHBAvfkgbNxu4pPaZs7zokAihYZ4z1sxtbjy:N5VAoJ xNOiqxIHEHB4tLp/YZ4zytbLK
Size: 244707 bytes
File type: EXE
Platform: WIN32
Entropy: Packed
PEID: UPolyXv05_v6
Company: no certificate found
Created at: 2013-01-26 14:57:35


Summary:

Worm. A program that is primarily replicating on networks or removable drives.

Payload

Behaviour Description
WormAutorun A worm can spread via removable drives. It writes its executable and creates "autorun.inf" scripts on all removable drives. The autorun script will execute the Worm's file once a user opens a drive's folder in Windows Explorer.
IRCBot A bot can communicate with command and control servers via IRC channel.
MSNWorm A worm can spread its copies through the MSN Messanger.
DNSBlocker A program can block designated DNS servers for making it difficult for users to locate specific domains or web sites on the Internet.
UDPFlooder This program can make a UDP flood. A UDP flood attack is a denial-of-service attack using the User Datagram Protocol (UDP). It can be initiated by sending a large number of UDP packets to random ports on a remote host.
SYNFlooder This program can make a SYN flood. It is a form of denial-of-service attack in which an attacker sends a succession of SYN requests to a target's system in an attempt to consume enough server resources to make the system unresponsive to legitimate traffic.
Trojan-Proxy This program can launch a proxy server (SOCKS4) on a designated TCP port.
USBInfector A program can register a device notification with the help of RegisterDeviceNotification. So it is notified when a USB device is plugged and then the worm copies itself to the USB device plugged into the affected computer.


Process activity

The Worm creates the following process(es):

81f1f333bf0985c0daf0aee13a2b1cdf.exe:208
81f1f333bf0985c0daf0aee13a2b1cdf.exe:1848
81f1f333bf0985c0daf0aee13a2b1cdf.exe:968
Reader_sl.exe:1064

The Worm injects its code into the following process(es):

mspaint.exe:216

File activity

The process 81f1f333bf0985c0daf0aee13a2b1cdf.exe:1848 makes changes in a file system.
The Worm creates and/or writes to the following file(s):

%Documents and Settings%\%current user%\Application Data\temp.bin (1281 bytes)

The process 81f1f333bf0985c0daf0aee13a2b1cdf.exe:968 makes changes in a file system.
The Worm creates and/or writes to the following file(s):

%WinDir%\explorer.exe.local (12 bytes)
%WinDir%\Wplugin.dll (601 bytes)
%WinDir%\ws2help.dll (2755 bytes)

The process mspaint.exe:216 makes changes in a file system.
The Worm creates and/or writes to the following file(s):

%Documents and Settings%\%current user%\Local Settings\Temporary Internet Files\Content.IE5\desktop.ini (67 bytes)
%Documents and Settings%\%current user%\Application Data\Microsoft\Pukmkb.exe (1281 bytes)
%Documents and Settings%\%current user%\Local Settings\Temporary Internet Files\Content.IE5\85OL8DWT\desktop.ini (67 bytes)
%Documents and Settings%\%current user%\Local Settings\Temporary Internet Files\Content.IE5\LLD5DBNN\desktop.ini (67 bytes)
%Documents and Settings%\%current user%\Local Settings\Temporary Internet Files\Content.IE5\KDA3SLU7\desktop.ini (67 bytes)
%Documents and Settings%\%current user%\Local Settings\Temporary Internet Files\Content.IE5\6FAH65KD\desktop.ini (67 bytes)

The Worm deletes the following file(s):

C:\81f1f333bf0985c0daf0aee13a2b1cdf.exe (0 bytes)

Registry activity

The process 81f1f333bf0985c0daf0aee13a2b1cdf.exe:208 makes changes in a system registry.
The Worm creates and/or sets the following values in system registry:

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "42 D1 34 9D 0B 96 D0 54 B6 AF 2F FD D9 B5 DD 6A"

[HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders]
"AppData" = "%Documents and Settings%\%current user%\Application Data"

The process 81f1f333bf0985c0daf0aee13a2b1cdf.exe:1848 makes changes in a system registry.
The Worm creates and/or sets the following values in system registry:

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "A8 04 4D 89 33 D6 B2 FD 6D 6A DE 83 9E 6B DF 3F"

[HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders]
"AppData" = "%Documents and Settings%\%current user%\Application Data"

The process Reader_sl.exe:1064 makes changes in a system registry.
The Worm creates and/or sets the following values in system registry:

[HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\MountPoints2\{c155cd73-744b-11e2-8294-806d6172696f}]
"BaseClass" = "Drive"

[HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders]
"AppData" = "%Documents and Settings%\%current user%\Application Data"

[HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\MountPoints2\{c155cd72-744b-11e2-8294-806d6172696f}]
"BaseClass" = "Drive"

[HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\MountPoints2\{b98117e8-75ca-11e2-81b2-000c293708fb}]
"BaseClass" = "Drive"

[HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\MountPoints2\{c155cd75-744b-11e2-8294-806d6172696f}]
"BaseClass" = "Drive"

The process mspaint.exe:216 makes changes in a system registry.
The Worm creates and/or sets the following values in system registry:

[HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings\Cache\Paths]
"Directory" = "%Documents and Settings%\%current user%\Local Settings\Temporary Internet Files\Content.IE5"

[HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings\Cache\Paths\path4]
"CacheLimit" = "65452"

[HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings\Cache\Paths\path4]
"CachePath" = "%Documents and Settings%\%current user%\Local Settings\Temporary Internet Files\Content.IE5\Cache4"

[HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings\Cache\Paths\path2]
"CacheLimit" = "65452"

[HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders]
"AppData" = "%Documents and Settings%\%current user%\Application Data"

[HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders]
"Cookies" = "%Documents and Settings%\%current user%\Cookies"

[HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings\Cache\Paths\path2]
"CachePath" = "%Documents and Settings%\%current user%\Local Settings\Temporary Internet Files\Content.IE5\Cache2"

[HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders]
"Common AppData" = "%Documents and Settings%\All Users\Application Data"

[HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders]
"Cache" = "%Documents and Settings%\%current user%\Local Settings\Temporary Internet Files"

[HKLM\System\CurrentControlSet\Hardware Profiles\0001\Software\Microsoft\windows\CurrentVersion\Internet Settings]
"ProxyEnable" = "0"

[HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings\Cache\Paths\path1]
"CacheLimit" = "65452"

[HKCU\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Connections]
"SavedLegacySettings" = "3C 00 00 00 16 00 00 00 01 00 00 00 00 00 00 00"

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "2B 76 62 F7 8E 96 22 98 0A 3A 8E 19 1E 33 DB 89"

[HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings\Cache\Paths\path1]
"CachePath" = "%Documents and Settings%\%current user%\Local Settings\Temporary Internet Files\Content.IE5\Cache1"

[HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings\Cache\Paths\path3]
"CacheLimit" = "65452"

[HKCU\Software\Microsoft\Windows\CurrentVersion\Internet Settings]
"MigrateProxy" = "1"

[HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders]
"History" = "%Documents and Settings%\%current user%\Local Settings\History"

[HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings\Cache\Paths\path3]
"CachePath" = "%Documents and Settings%\%current user%\Local Settings\Temporary Internet Files\Content.IE5\Cache3"

[HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings\Cache\Paths]
"Paths" = "4"

The Worm modifies IE settings for security zones to map all local web-nodes with no dots which do not refer to any zone to the Intranet Zone:

[HKCU\Software\Microsoft\Windows\CurrentVersion\Internet Settings\ZoneMap]
"UNCAsIntranet" = "1"

The Worm modifies IE settings for security zones to map all web-nodes that bypassing proxy to the Intranet Zone:

[HKCU\Software\Microsoft\Windows\CurrentVersion\Internet Settings\ZoneMap]
"ProxyBypass" = "1"

Proxy settings are disabled:

[HKCU\Software\Microsoft\Windows\CurrentVersion\Internet Settings]
"ProxyEnable" = "0"

The Worm modifies IE settings for security zones to map all urls to the Intranet Zone:

[HKCU\Software\Microsoft\Windows\CurrentVersion\Internet Settings\ZoneMap]
"IntranetName" = "1"

To automatically run itself each time Windows is booted, the Worm adds the following link to its file to the system registry autorun key:

[HKCU\Software\Microsoft\Windows\CurrentVersion\Run]
"Pukmkb" = "%Documents and Settings%\%current user%\Application Data\Microsoft\Pukmkb.exe"

The Worm deletes the following value(s) in system registry:

[HKCU\Software\Microsoft\Windows\CurrentVersion\Internet Settings]
"AutoConfigURL"

[HKCU\Software\Microsoft\Windows\CurrentVersion\Internet Settings]
"ProxyServer"

[HKCU\Software\Microsoft\Windows\CurrentVersion\Internet Settings]
"ProxyOverride"

Network activity (URLs)

No activity has been detected.

Rootkit activity

The Worm installs the following user-mode hooks in WININET.dll:

HttpSendRequestW
InternetWriteFile
HttpSendRequestA

The Worm installs the following user-mode hooks in dnsapi.dll:

DnsQuery_A
DnsQuery_W

The Worm installs the following user-mode hooks in WS2_32.dll:

send
GetAddrInfoW

The Worm installs the following user-mode hooks in kernel32.dll:

MoveFileA
CopyFileW
CopyFileA
MoveFileW
CreateFileW
CreateFileA

The Worm installs the following user-mode hooks in ntdll.dll:

LdrLoadDll
NtResumeThread
NtQueryDirectoryFile
NtEnumerateValueKey

Propagation

A worm can spread via removable drives. It writes its executable and creates "autorun.inf" scripts on all removable drives. The autorun script will execute the Worm's file once a user opens a drive's folder in Windows Explorer.
A program can register a device notification with the help of RegisterDeviceNotification. So it is notified when a USB device is plugged and then the worm copies itself to the USB device plugged into the affected computer.
A worm can spread its copies through the MSN Messanger.


Remove it with Ad-Aware

  1. Click (here) to download and install Ad-Aware Free Antivirus.
  2. Update the definition files.
  3. Run a full scan of your computer.


Manual removal*

  1. Scan a system with an anti-rootkit tool.
  2. Terminate malicious process(es) (How to End a Process With the Task Manager):

    81f1f333bf0985c0daf0aee13a2b1cdf.exe:208
    81f1f333bf0985c0daf0aee13a2b1cdf.exe:1848
    81f1f333bf0985c0daf0aee13a2b1cdf.exe:968

  3. Delete the original Worm file.
  4. Delete or disinfect the following files created/modified by the Worm:

    %Documents and Settings%\%current user%\Application Data\temp.bin (1281 bytes)
    %WinDir%\explorer.exe.local (12 bytes)
    %WinDir%\Wplugin.dll (601 bytes)
    %WinDir%\ws2help.dll (2755 bytes)
    %Documents and Settings%\%current user%\Local Settings\Temporary Internet Files\Content.IE5\desktop.ini (67 bytes)
    %Documents and Settings%\%current user%\Application Data\Microsoft\Pukmkb.exe (1281 bytes)
    %Documents and Settings%\%current user%\Local Settings\Temporary Internet Files\Content.IE5\85OL8DWT\desktop.ini (67 bytes)
    %Documents and Settings%\%current user%\Local Settings\Temporary Internet Files\Content.IE5\LLD5DBNN\desktop.ini (67 bytes)
    %Documents and Settings%\%current user%\Local Settings\Temporary Internet Files\Content.IE5\KDA3SLU7\desktop.ini (67 bytes)
    %Documents and Settings%\%current user%\Local Settings\Temporary Internet Files\Content.IE5\6FAH65KD\desktop.ini (67 bytes)

  5. Delete the following value(s) in the autorun key (How to Work with System Registry):

    [HKCU\Software\Microsoft\Windows\CurrentVersion\Run]
    "Pukmkb" = "%Documents and Settings%\%current user%\Application Data\Microsoft\Pukmkb.exe"

  6. Find and delete all copies of the worm's file together with "autorun.inf" scripts on removable drives.
  7. Reboot the computer.

*Manual removal may cause unexpected system behaviour and should be performed at your own risk.