Worm.Win32.Ainslot.VB_aae700a9d8

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.

Process activity

The Worm creates the following process(es):

%original file name%.exe:1480
reg.exe:1608
reg.exe:892
reg.exe:448
reg.exe:1564
rundll32.exe:340
dumprep.exe:872
dumprep.exe:816

The Worm injects its code into the following process(es):No processes have been created.

File activity

The process %original file name%.exe:1480 makes changes in the file system.

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

%Documents and Settings%\%current user%\Start Menu\Programs\Startup\Win32.lnk (2 bytes)

The process dumprep.exe:872 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\WER4e2c.dir00\svchost.exe.hdmp (179453 bytes)

The process dumprep.exe:816 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\WER4e2c.dir00\svchost.exe.mdmp (79691 bytes)

Registry activity

The process %original file name%.exe:1480 makes changes in the system registry.

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

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "6E 57 FF FB 86 AA DB 5C C2 9E 97 54 F6 20 E5 43"

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

[HKCU\Software\Microsoft\Windows NT\CurrentVersion\Winlogon]
"shell" = "%AppData%\Microsoft\DeciUpd.exe,explorer.exe"

[HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders]
"Startup" = "%Documents and Settings%\%current user%\Start Menu\Programs\Startup"

[HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders]
"CommonVideo" = "%Documents and Settings%\All Users\Documents\My Videos"

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

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

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

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

[HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders]
"CommonMusic" = "%Documents and Settings%\All Users\Documents\My Music"

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

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

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

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

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

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

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

[HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders]
"CommonPictures" = "%Documents and Settings%\All Users\Documents\My Pictures"

[HKCU\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer\Run]
"DeciUpd" = "%AppData%\Microsoft\DeciUpd.exe"

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]
"DeciUpd" = "%AppData%\Microsoft\DeciUpd.exe"

The process reg.exe:1608 makes changes in the system registry.

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

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "FB B8 08 90 CD 15 61 FF 00 7A E7 F7 A1 4F 82 9E"

[HKLM\System\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile]
"DoNotAllowExceptions" = "0"

The process reg.exe:892 makes changes in the system registry.

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

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "7C C5 09 B3 6A A6 12 BA 7B 8B 4D E7 EA 3B 5E 3B"

Adds a rule to the firewall Windows which allows any network activity:

[HKLM\System\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List\C:\DOCUME~1\"%CurrentUserName%"\LOCALS~1\Temp]
"AA.exe" = "C:\DOCUME~1\"%CurrentUserName%"\LOCALS~1\Temp\AA.exe:*:Enabled:Windows Messanger"

The process reg.exe:448 makes changes in the system registry.

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

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "D9 71 F8 C8 EE BC 42 D8 4F B5 D3 5F 25 DF 90 CA"

Adds a rule to the firewall Windows which allows any network activity:

[HKLM\System\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List\C:\Windows\System32]
"svchost.exe" = "C:\Windows\System32\svchost.exe:*:Enabled:Windows Messanger"

The process reg.exe:1564 makes changes in the system registry.

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

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "AC C0 18 07 14 FE 92 57 8C 49 F1 4F BC 29 53 B0"

[HKLM\System\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile]
"DoNotAllowExceptions" = "0"

The process rundll32.exe:340 makes changes in the system registry.

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

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "53 F2 4A 53 24 81 B1 59 C7 F6 1C 02 AD 9D CA D8"

[HKCU\Software\Microsoft\Windows\ShellNoRoam\MUICache\%System%]
"svchost.exe" = "Generic Host Process for Win32 Services"

[HKLM\System\CurrentControlSet\Control\Session Manager\AppCompatibility]
"AppCompatCache" = "EF BE AD DE 60 00 00 00 00 00 00 00 00 00 00 00"

[HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\AppCompatFlags\Layers\%System%]
"svchost.exe" = "EnableNXShowUI"

The process dumprep.exe:872 makes changes in the system registry.

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

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "D0 28 45 54 49 61 FB 9D C4 8B 43 28 46 48 39 35"

The process dumprep.exe:816 makes changes in the system registry.

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

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "D3 22 76 14 F3 17 1F AF A0 D8 EC CC FD 36 C0 54"

Network activity (URLs)

No activity has been detected.

HOSTS file anomalies

No changes have been detected.

Rootkit activity

No anomalies have been detected.

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.

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. Terminate malicious process(es) (How to End a Process With the Task Manager):

   %original file name%.exe:1480
   reg.exe:1608
   reg.exe:892
   reg.exe:448
   reg.exe:1564
   rundll32.exe:340
   dumprep.exe:872
   dumprep.exe:816

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

   %Documents and Settings%\%current user%\Start Menu\Programs\Startup\Win32.lnk (2 bytes)
   %Documents and Settings%\%current user%\Local Settings\Temp\WER4e2c.dir00\svchost.exe.hdmp (179453 bytes)
   %Documents and Settings%\%current user%\Local Settings\Temp\WER4e2c.dir00\svchost.exe.mdmp (79691 bytes)

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

   [HKCU\Software\Microsoft\Windows\CurrentVersion\Run]
   "DeciUpd" = "%AppData%\Microsoft\DeciUpd.exe"

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