Worm.Win32.Ainslot.VB_7a2df6664f

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):

reg.exe:2024
reg.exe:2248
reg.exe:2400
reg.exe:2416
ctfmon.exe:252
AppLaunch.exe:2460
AppLaunch.exe:936

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

nwtray.exe:2272
%original file name%.exe:2420
nvxdsinc.exe:1904

File activity

The process AppLaunch.exe:936 makes changes in the file system.

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

%Documents and Settings%\%current user%\Application Data\csrsc.exe (59 bytes)
%Documents and Settings%\%current user%\Application Data\KEY (34 bytes)

The process %original file name%.exe:2420 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\System\nwtray.exe (1281 bytes)
%Documents and Settings%\%current user%\Local Settings\Temp\System\nvxdsinc.exe (42 bytes)

Registry activity

The process reg.exe:2024 makes changes in the system registry.

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

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "2A 9E 43 12 E6 D0 02 96 AA 39 80 DC EF 8A D6 51"

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

The process reg.exe:2248 makes changes in the system registry.

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

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "28 77 63 A6 CE BA 26 A0 06 0F 19 2E 0D 9E BD 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]
"csrsc.exe" = "%Documents and Settings%\%current user%\Application Data\csrsc.exe:*:Enabled:Windows Messanger"

The process reg.exe:2400 makes changes in the system registry.

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

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "F4 2A 21 0F C1 AD 8E 44 A9 B6 9E 8D FD 86 5D 6A"

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

The process reg.exe:2416 makes changes in the system registry.

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

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "6D 0A 2D 49 13 F3 A2 35 56 A5 80 01 38 C9 3B C1"

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

[HKLM\System\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List\%WinDir%\Microsoft.NET\Framework\v2.0.50727]
"AppLaunch.exe" = "%WinDir%\Microsoft.NET\Framework\v2.0.50727\AppLaunch.exe:*:Enabled:Windows Messanger"

The process ctfmon.exe:252 makes changes in the system registry.

The Worm deletes the following value(s) in system registry:

The Worm disables automatic startup of the application by deleting the following autorun value:

[HKCU\Software\Microsoft\Windows\CurrentVersion\Run]
"internat.exe"

The process nwtray.exe:2272 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 00 74 E6 1D FA 86 27 4E BB 8D 02 2F 07 2F 7B"

[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 AppLaunch.exe:2460 makes changes in the system registry.

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

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "32 5E 12 F5 23 3D C4 25 EA 2C CD A4 04 A3 AA D2"

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

The process AppLaunch.exe:936 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 08 01 41 2D 34 73 A9 26 6B 0B D8 01 8F 75 C6"

[HKCU\Software\VB and VBA Program Settings\INSTALL\DATE]
"UQFR8F0TQ5" = "November 19, 2013"

[HKCU\Software\VB and VBA Program Settings\SrvID\ID]
"UQFR8F0TQ5" = "NET"

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

[HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\policies\Explorer\run]
"Framework" = "%Documents and Settings%\%current user%\Application Data\csrsc.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:

[HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run]
"Framework" = "%Documents and Settings%\%current user%\Application Data\csrsc.exe"

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

The process %original file name%.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" = "19 CA 0A 79 65 01 F3 37 91 94 3B 7C 5F 0D 02 26"

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

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

[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"
"Cookies" = "%Documents and Settings%\%current user%\Cookies"

[HKCU\Software\Microsoft\Windows\ShellNoRoam\MUICache\%Documents and Settings%\%current user%\Local Settings\Temp\System]
"nvxdsinc.exe" = "NVIDIA User Experience Driver Component"

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

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

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:

"UNCAsIntranet" = "1"

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

"IntranetName" = "1"

The process nvxdsinc.exe:1904 makes changes in the system registry.

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

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "FD E5 74 03 10 58 9B C9 B0 29 BE D3 C2 59 E2 4A"

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

[HKCU\Software\Microsoft\Windows\CurrentVersion\Internet Settings\ZoneMap]
"AutoDetect" = "1"
[HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\MountPoints2\{773a730e-74fb-11e2-b597-000c293bdf2f}]
"BaseClass" = "Drive"

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

[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"
"Cookies" = "%Documents and Settings%\%current user%\Cookies"

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

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

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:

"UNCAsIntranet" = "1"

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]
"Microsoft® Windows® Operating System" = "%Documents and Settings%\%current user%\Local Settings\Temp\System\nvxdsinc.exe"

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

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

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):

   reg.exe:2024
   reg.exe:2248
   reg.exe:2400
   reg.exe:2416
   AppLaunch.exe:2460
   AppLaunch.exe:936
   

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

   %Documents and Settings%\%current user%\Application Data\csrsc.exe (59 bytes)
   %Documents and Settings%\%current user%\Application Data\KEY (34 bytes)
   %Documents and Settings%\%current user%\Local Settings\Temp\System\nwtray.exe (1281 bytes)
   %Documents and Settings%\%current user%\Local Settings\Temp\System\nvxdsinc.exe (42 bytes)

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

   [HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run]
   "Framework" = "%Documents and Settings%\%current user%\Application Data\csrsc.exe"
   
   [HKCU\Software\Microsoft\Windows\CurrentVersion\Run]
   "Framework" = "%Documents and Settings%\%current user%\Application Data\csrsc.exe"
   
   [HKCU\Software\Microsoft\Windows\CurrentVersion\Run]
   "Microsoft® Windows® Operating System" = "%Documents and Settings%\%current user%\Local Settings\Temp\System\nvxdsinc.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