Worm.Win32.Dorkbot_a8884c420e

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):

a8884c420e5f2ce410fa1360dd722b0a.exe:1284
2.exe:456
1.exe:364
1.exe:744

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

temp135025208.exe:516

File activity

The process 2.exe:456 makes changes in a file system.

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

%Documents and Settings%\%current user%\Local Settings\Temp\temp135025208.exe (3909 bytes)

The process temp135025208.exe:516 makes changes in a file system.

The Worm deletes the following file(s):

%Documents and Settings%\%current user%\Local Settings\Temp\tmp.exe (0 bytes)

Registry activity

The process a8884c420e5f2ce410fa1360dd722b0a.exe:1284 makes changes in a system registry.

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

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "2B A6 1F AE 82 72 47 D4 90 E7 8E B1 86 F6 74 BC"

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

The process 2.exe:456 makes changes in a system registry.

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

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "D0 8C 4A 81 D4 72 7D E8 C6 21 F1 D5 54 FE 2F 0D"

The process temp135025208.exe:516 makes changes in a system registry.

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

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "D9 09 31 D0 32 15 36 3E 22 28 37 3D E2 77 3D 1E"

[HKCU\Software\Microsoft\Notepad]
"sizeCompletedValid" = "DMr7ECZt8AEMJY4qik4OMziVoqo tRnMxcO/WdL154xjrpaVOrXNhiqV02lV9zgvkQ=="

[HKCU\Software\Sysinternals\Process Monitor]
"UrlEnabledUse" = "80"

[HKLM\System\CurrentControlSet\Services\nm\Parameters]
"EnableStationQueries" = "1"

[HKLM\System\CurrentControlSet\Services\nm\Parameters]
"ComputerName" = "XP10"

[HKCU\Software\Microsoft\Notepad]
"infoPlayedCurrent" = "00 00 00 00 00 00 00 00"

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

[HKCU\Software\Microsoft\Internet Explorer\Main]
"DBSavedUse" = "A2 49 4D F3 D9 1E 9F 88 01 01 08 61 00 02 01 10"

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

[HKCU\Software\Sysinternals\Process Monitor]
"FlagsModifiedValid" = "00 00 00 00 00 00 00 00"

[HKCU\Software\Microsoft\Notepad]
"styleModifiedPrev" = "80"

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

[HKCU\Software\Microsoft\Internet Explorer\Main]
"PlatformCompressedValid" = "00 00 00 00 00 00 00 00"

[HKCU\Software\Microsoft\Internet Explorer\Main]
"PersistentLocalizedName" = "28 80 F9 7F 7A 74 F0 EC BA 96 4A C9 C0 EC 09 56"

[HKCU\Software\Sysinternals\Process Monitor]
"DefaultCompressedRecord" = "28 80 F9 7F 73 6A 65 C0 9D CA C7 F7 5F CB C6 DE"

[HKCU\Software\Microsoft\Notepad]
"activeModifiedTheme" = "28 80 F9 7F 87 DE EE E5 C3 F9 22 3C E3 90 BB 4E"

[HKCU\Software\Microsoft\Internet Explorer\Main]
"RecordEnabledCheck" = "80"

[HKCU\Software\Sysinternals\Process Monitor]
"RecordModifiedMax" = "DMr7ECZt8AEMJY4qik4OMziVoqo tRnMxcO/WdL154xjrpaVOrXNhiqV02lV9zgvkQ=="

[HKLM\System\CurrentControlSet\Services\nm\Parameters]
"UserName" = "%CurrentUserName%"

[HKCU\Software\Microsoft\Internet Explorer\Main]
"LineLoadedQuick" = "DMr7ECZt8AEMJY4qik4OMziVoqo tRnMxcO/WdL154xjrpaVOrXNhiqV02lV9zgvkQ=="

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

[HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run]
"NetworkUpdater" = "C:\DOCUME~1\"%CurrentUserName%"\LOCALS~1\Temp\temp135025208.exe"

The process 1.exe:364 makes changes in a system registry.

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

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "37 0C 3D 17 49 1D 06 96 D7 C2 22 44 D8 D6 55 63"

The process 1.exe:744 makes changes in a system registry.

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

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "76 E6 97 47 8A CC F3 ED AA 71 B9 D9 81 92 65 71"

Network activity (URLs)

URL	IP
hxxp://st4.divshare.com/direct.php?f=24577101&s=75c.res	208.100.16.112
hxxp://st4.divshare.com/launch.php?f=24577101&s=75c&is_direct=true
hxxp://topcongo.be/site2/images/now.exe (Malicious)	213.186.33.19
hxxp://91.234.64.114/boris02.exe (Malicious)

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.

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):

   a8884c420e5f2ce410fa1360dd722b0a.exe:1284
   2.exe:456
   1.exe:364
   1.exe:744

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\temp135025208.exe (3909 bytes)

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

   [HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run]
   "NetworkUpdater" = "C:\DOCUME~1\"%CurrentUserName%"\LOCALS~1\Temp\temp135025208.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