Worm.Win32.Dorkbot_6a99dcfb7d

Dynamic Analysis

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):

%original file name%.exe:1508
%original file name%.exe:900
%original file name%.exe:1360
Ctkmko.exe:1556
Ctkmko.exe:1752
Ctkmko.exe:1088

File activity

The process %original file name%.exe:1508 makes changes in the file system.

The Worm creates and/or writes to the following file(s):

%Documents and Settings%\%current user%\Local Settings\Temp\J7ygghyk6L1AItgfM1t.tmp (3 bytes)
%Documents and Settings%\%current user%\Application Data\Microsoft\Crypto\RSA\S-1-5-21-1844237615-1960408961-1801674531-1003\c5b88721db08c824db69d0bbc702beb8_75ed9567-aa58-4c8e-a8ea-3cad7c47ab03 (44 bytes)

The process %original file name%.exe:900 makes changes in the file system.

The Worm creates and/or writes to the following file(s):

%Documents and Settings%\%current user%\Application Data\Ctkmko.exe (673 bytes)

The process Ctkmko.exe:1088 makes changes in the file system.

The Worm creates and/or writes to the following file(s):

%Documents and Settings%\%current user%\Local Settings\Temp\J7ygghyk6L1AItgfM1t.tmp (3 bytes)

Registry activity

The process %original file name%.exe:1508 makes changes in the system registry.

The Worm creates and/or sets the following values in system registry:

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "F9 F9 D9 69 EB F7 83 85 50 77 69 21 5E 50 EE C2"

The process %original file name%.exe:900 makes changes in the system registry.

The Worm creates and/or sets the following values in system registry:

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "BA 0E 99 07 59 2B E0 AB 45 D3 BA 32 AD 94 6D F2"

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

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]
"Ctkmko" = "%Documents and Settings%\%current user%\Application Data\Ctkmko.exe"

The process %original file name%.exe:1360 makes changes in the system registry.

The Worm creates and/or sets the following values in system registry:

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "F2 C9 D2 C2 31 E7 8F 42 E5 7E F8 DD 12 80 D8 45"

The process Ctkmko.exe:1556 makes changes in the system registry.

The Worm creates and/or sets the following values in system registry:

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "A1 D1 DA 4F 4B BB 79 76 44 C8 77 45 1D 28 E1 7F"

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

The process Ctkmko.exe:1752 makes changes in the system registry.

The Worm creates and/or sets the following values in system registry:

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "59 09 69 4D D3 36 8D 60 D7 FB 1B 02 6A C7 AA F7"

The process Ctkmko.exe:1088 makes changes in the system registry.

The Worm creates and/or sets the following values in system registry:

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "B5 AB 08 89 0D 91 08 4C 53 AB 61 81 E9 9E 47 81"

Network activity (URLs)

URL	IP
update.jebac.net	Unresolvable

HOSTS file anomalies

No changes have 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 ADVAPI32.dll:

RegCreateKeyExA
RegCreateKeyExW

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

send
getaddrinfo

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.

Removals

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):

   %original file name%.exe:1508
   %original file name%.exe:900
   %original file name%.exe:1360
   Ctkmko.exe:1556
   Ctkmko.exe:1752
   Ctkmko.exe:1088

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

   %Documents and Settings%\%current user%\Local Settings\Temp\J7ygghyk6L1AItgfM1t.tmp (3 bytes)
   %Documents and Settings%\%current user%\Application Data\Microsoft\Crypto\RSA\S-1-5-21-1844237615-1960408961-1801674531-1003\c5b88721db08c824db69d0bbc702beb8_75ed9567-aa58-4c8e-a8ea-3cad7c47ab03 (44 bytes)
   %Documents and Settings%\%current user%\Application Data\Ctkmko.exe (673 bytes)
   

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

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

6. Clean the Temporary Internet Files folder, which may contain infected files (How to clean Temporary Internet Files folder).
   
7. Find and delete all copies of the worm's file together with "autorun.inf" scripts on removable drives.
   
8. Reboot the computer.
   

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

Static Analysis

Network Activity

Map

Strings from Dumps