Worm.Win32.Ainslot.VB_c33e6d2982

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:1268
taznact.exe:1464
WScript.exe:2420
rundll32.exe:848
reg.exe:2640
reg.exe:2620
reg.exe:2628
reg.exe:2612
dumprep.exe:820
dumprep.exe:2952

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

File activity

The process %original file name%.exe:1268 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\taznact.exe (40388 bytes)

The process taznact.exe:1464 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\1.vbs (894 bytes)
%Documents and Settings%\%current user%\Local Settings\Temp\Tar2.tmp (2712 bytes)
%Documents and Settings%\%current user%\Local Settings\Temp\Cab5.tmp (54 bytes)
%Documents and Settings%\%current user%\Application Data\Microsoft\CryptnetUrlCache\MetaData\2BF68F4714092295550497DD56F57004 (408 bytes)
%Documents and Settings%\%current user%\Application Data\Microsoft\CryptnetUrlCache\Content\94308059B57B3142E455B38A6EB92015 (54 bytes)
%Documents and Settings%\%current user%\Application Data\Microsoft\CryptnetUrlCache\MetaData\94308059B57B3142E455B38A6EB92015 (408 bytes)
%Documents and Settings%\%current user%\Local Settings\Temp\Cab1.tmp (49 bytes)
%Documents and Settings%\%current user%\Local Settings\Temp\Tar6.tmp (2712 bytes)
%Documents and Settings%\%current user%\Local Settings\Temp\Tar4.tmp (2712 bytes)
%Documents and Settings%\%current user%\Application Data\DataWork\taznact.exe (1425 bytes)
%Documents and Settings%\%current user%\Application Data\Microsoft\CryptnetUrlCache\Content\2BF68F4714092295550497DD56F57004 (18 bytes)
%Documents and Settings%\%current user%\Local Settings\Temp\Cab3.tmp (49 bytes)

The Worm deletes the following file(s):

%Documents and Settings%\%current user%\Local Settings\Temp\Tar2.tmp (0 bytes)
%Documents and Settings%\%current user%\Local Settings\Temp\Cab5.tmp (0 bytes)
%Documents and Settings%\%current user%\Local Settings\Temp\Cab1.tmp (0 bytes)
%Documents and Settings%\%current user%\Local Settings\Temp\Tar6.tmp (0 bytes)
%Documents and Settings%\%current user%\Local Settings\Temp\Tar4.tmp (0 bytes)
%Documents and Settings%\%current user%\Local Settings\Temp\Cab3.tmp (0 bytes)

The process WScript.exe:2420 makes changes in the file system.

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

%Documents and Settings%\%current user%\Application Data\Sample.lnk (793 bytes)

The Worm deletes the following file(s):

%Documents and Settings%\%current user%\Local Settings\Temp\1.vbs (0 bytes)

The process dumprep.exe:820 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\WERbb24.dir00\svchost.exe.mdmp (100029 bytes)

The process dumprep.exe:2952 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\WERbb24.dir00\svchost.exe.hdmp (218897 bytes)

Registry activity

The process %original file name%.exe:1268 makes changes in the system registry.

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

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "5C EE 74 E5 EF 75 6E 22 EA 70 58 9F 57 AB D3 75"

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

The process taznact.exe:1464 makes changes in the system registry.

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

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "09 04 AD A9 1B BD 78 0C 28 00 0A B7 40 6A A1 BB"

[HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\MountPoints2\{fdd9f6f3-7454-11e2-b4cd-806d6172696f}]
"BaseClass" = "Drive"

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

[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\{773a730e-74fb-11e2-b597-000c293bdf2f}]
"BaseClass" = "Drive"

[HKCU\S]
"E" = "1"

[HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\MountPoints2\{fdd9f6f2-7454-11e2-b4cd-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\{fdd9f6f5-7454-11e2-b4cd-806d6172696f}]
"BaseClass" = "Drive"

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

[HKCU\Software\Microsoft\Windows\ShellNoRoam\MUICache\%WinDir%\System32]
"WScript.exe" = "Microsoft (R) Windows Based Script Host"

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

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

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:

"ProxyBypass" = "1"

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

"IntranetName" = "1"

The process WScript.exe:2420 makes changes in the system registry.

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

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "C0 4E 2C 91 4C 1F E3 87 0D 7D 17 4F D7 4F 80 72"

[HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\MountPoints2\{fdd9f6f3-7454-11e2-b4cd-806d6172696f}]
"BaseClass" = "Drive"

[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\{773a730e-74fb-11e2-b597-000c293bdf2f}]
"BaseClass" = "Drive"

[HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\MountPoints2\{fdd9f6f2-7454-11e2-b4cd-806d6172696f}]
"BaseClass" = "Drive"

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

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

[HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\MountPoints2\{fdd9f6f5-7454-11e2-b4cd-806d6172696f}]
"BaseClass" = "Drive"

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

[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"

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\RunOnce]
"sidebar" = "%Documents and Settings%\%current user%\Application Data\Sample.lnk"

The process rundll32.exe:848 makes changes in the system registry.

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

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "22 3C FA 58 5D 1E F6 5F 5C 20 F9 75 EB 7D 86 41"

[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 reg.exe:2640 makes changes in the system registry.

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

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "6A 0C 1A 27 EE 85 A3 51 23 6D 21 64 5D 01 D3 8B"

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

The process reg.exe:2620 makes changes in the system registry.

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

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "F3 62 F2 B2 89 BE D4 BF 29 F4 0C C5 3C 18 E6 7D"

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

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

The process reg.exe:2628 makes changes in the system registry.

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

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "0C 75 9A FB B6 66 5F 0E FF CE 40 A8 C5 5E 7D 22"

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\Microsoft]
"2.exe" = "%Documents and Settings%\%current user%\Application Data\Microsoft\2.exe:*:Enabled:Windows Messanger"

The process reg.exe:2612 makes changes in the system registry.

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

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "17 A5 52 70 81 32 78 DA 75 CD B6 8F 51 85 CF EE"

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

The process dumprep.exe:820 makes changes in the system registry.

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

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "4A F2 26 08 0B EF 2D FD E3 64 63 50 73 5E B1 24"

The process dumprep.exe:2952 makes changes in the system registry.

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

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "A9 16 AA 43 61 56 EA 3C 0B A3 F1 99 F2 49 7A 56"

Network activity (URLs)

URL	IP
hxxp://tazbox.zapto.org/downloader/sll.exe (Malicious)	31.6.35.84
hxxp://a26.d.akamai.net/msdownload/update/v3/static/trustedr/en/authrootseq.txt
hxxp://a26.d.akamai.net/msdownload/update/v3/static/trustedr/en/authrootstl.cab
www.download.windowsupdate.com	205.234.225.88

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:1268
   taznact.exe:1464
   WScript.exe:2420
   rundll32.exe:848
   reg.exe:2640
   reg.exe:2620
   reg.exe:2628
   reg.exe:2612
   dumprep.exe:820
   dumprep.exe:2952

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\taznact.exe (40388 bytes)
   %Documents and Settings%\%current user%\Local Settings\Temp\1.vbs (894 bytes)
   %Documents and Settings%\%current user%\Local Settings\Temp\Tar2.tmp (2712 bytes)
   %Documents and Settings%\%current user%\Local Settings\Temp\Cab5.tmp (54 bytes)
   %Documents and Settings%\%current user%\Application Data\Microsoft\CryptnetUrlCache\MetaData\2BF68F4714092295550497DD56F57004 (408 bytes)
   %Documents and Settings%\%current user%\Application Data\Microsoft\CryptnetUrlCache\Content\94308059B57B3142E455B38A6EB92015 (54 bytes)
   %Documents and Settings%\%current user%\Application Data\Microsoft\CryptnetUrlCache\MetaData\94308059B57B3142E455B38A6EB92015 (408 bytes)
   %Documents and Settings%\%current user%\Local Settings\Temp\Cab1.tmp (49 bytes)
   %Documents and Settings%\%current user%\Local Settings\Temp\Tar6.tmp (2712 bytes)
   %Documents and Settings%\%current user%\Local Settings\Temp\Tar4.tmp (2712 bytes)
   %Documents and Settings%\%current user%\Application Data\DataWork\taznact.exe (1425 bytes)
   %Documents and Settings%\%current user%\Application Data\Microsoft\CryptnetUrlCache\Content\2BF68F4714092295550497DD56F57004 (18 bytes)
   %Documents and Settings%\%current user%\Local Settings\Temp\Cab3.tmp (49 bytes)
   %Documents and Settings%\%current user%\Application Data\Sample.lnk (793 bytes)
   %Documents and Settings%\%current user%\Local Settings\Temp\WERbb24.dir00\svchost.exe.mdmp (100029 bytes)
   %Documents and Settings%\%current user%\Local Settings\Temp\WERbb24.dir00\svchost.exe.hdmp (218897 bytes)

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

   [HKCU\Software\Microsoft\Windows\CurrentVersion\RunOnce]
   "sidebar" = "%Documents and Settings%\%current user%\Application Data\Sample.lnk"

5. Clean the Temporary Internet Files folder, which may contain infected files (How to clean Temporary Internet Files folder).
   
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.

Static Analysis

Network Activity

Map

Strings from Dumps