Worm.Win32.Ainslot.VB_a3a51ad2e8

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):

rundll32.exe:1116
%original file name%.exe:284
reg.exe:424
reg.exe:1612
reg.exe:1604
reg.exe:1576
dumprep.exe:1616
dumprep.exe:828

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

1425900376.EXE:360

File activity

The process %original file name%.exe:284 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\1425900376.EXE (137 bytes)
%Documents and Settings%\%current user%\Local Settings\Temp\temp_ysBIjScqls\svchost.exe (7547 bytes)
%Documents and Settings%\%current user%\Local Settings\Temp\tmp1.tmp.exe (3730 bytes)

The Worm deletes the following file(s):

%Documents and Settings%\%current user%\Local Settings\Temp\tmp1.tmp (0 bytes)

The process dumprep.exe:1616 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\WER4b00.dir00\svchost.exe.mdmp (100867 bytes)

The process dumprep.exe:828 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\WER4b00.dir00\svchost.exe.hdmp (222995 bytes)

Registry activity

The process rundll32.exe:1116 makes changes in the system registry.

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

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "E9 0E 70 51 EA DD 6B 64 1A F9 D2 0C 5A F1 FB 37"

[HKCU\Software\Microsoft\Windows\ShellNoRoam\MUICache\%Documents and Settings%\%current user%\Local Settings\Temp\temp_ysBIjScqls]
"svchost.exe" = "Visual Basic Command Line Compiler"

[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\%Documents and Settings%\%current user%\Local Settings\Temp\temp_ysBIjScqls]
"svchost.exe" = "EnableNXShowUI"

The process 1425900376.EXE:360 makes changes in the system registry.

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

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "07 02 1A 25 C9 66 03 D5 90 72 D8 96 1A A1 71 5C"

The process %original file name%.exe:284 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 A2 B5 3D 79 96 B4 E1 01 62 39 6D C1 F9 5D 26"

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

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

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

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

[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\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"

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

"Personal" = "%Documents and Settings%\%current user%\My Documents"

[HKCU\Software\Microsoft\Windows\ShellNoRoam\MUICache\%Documents and Settings%\%current user%\Local Settings\Temp]
"1425900376.EXE" = "1425900376"

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]
"system.exe" = "%Documents and Settings%\%current user%\Local Settings\Temp\tmp1.tmp.exe"

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 urls to the Intranet Zone:

"IntranetName" = "1"

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

"ProxyBypass" = "1"

The process reg.exe:424 makes changes in the system registry.

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

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "66 35 DA 56 52 E0 11 1E A5 FA B0 59 38 4B 1A 05"

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

The process reg.exe:1612 makes changes in the system registry.

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

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "9A 32 13 17 E7 6D 16 15 33 29 C9 C0 A6 A3 F1 2B"

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

[HKLM\System\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List\%Documents and Settings%\%current user%\Application Data]
"ZQPV2L7C2K.exe" = "%Documents and Settings%\%current user%\Application Data\ZQPV2L7C2K.exe:*:Enabled:Windows Messanger"

The process reg.exe:1604 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 50 0F 25 BD 7B 37 79 D4 7B F7 D1 57 A9 DF F4"

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

The process reg.exe:1576 makes changes in the system registry.

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

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "37 F4 F5 8C 10 A2 74 6E F5 8F 04 C8 25 9A 10 FE"

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

[HKLM\System\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List\%Documents and Settings%\%current user%\Local Settings\Temp\temp_ysBIjScqls]
"svchost.exe" = "%Documents and Settings%\%current user%\Local Settings\Temp\temp_ysBIjScqls\svchost.exe:*:Enabled:Windows Messanger"

The process dumprep.exe:1616 makes changes in the system registry.

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

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "45 C8 AC 2C B8 A3 93 BD 21 89 57 B4 A3 C7 B5 3C"

The process dumprep.exe:828 makes changes in the system registry.

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

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "AE C0 FF 01 FA 4C 3C 94 70 2B B7 92 F6 46 B2 11"

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):

   rundll32.exe:1116
   %original file name%.exe:284
   reg.exe:424
   reg.exe:1612
   reg.exe:1604
   reg.exe:1576
   dumprep.exe:1616
   dumprep.exe:828

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

   %Documents and Settings%\%current user%\Local Settings\Temp\1425900376.EXE (137 bytes)
   %Documents and Settings%\%current user%\Local Settings\Temp\temp_ysBIjScqls\svchost.exe (7547 bytes)
   %Documents and Settings%\%current user%\Local Settings\Temp\tmp1.tmp.exe (3730 bytes)
   %Documents and Settings%\%current user%\Local Settings\Temp\WER4b00.dir00\svchost.exe.mdmp (100867 bytes)
   %Documents and Settings%\%current user%\Local Settings\Temp\WER4b00.dir00\svchost.exe.hdmp (222995 bytes)

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

   [HKCU\Software\Microsoft\Windows\CurrentVersion\Run]
   "system.exe" = "%Documents and Settings%\%current user%\Local Settings\Temp\tmp1.tmp.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