Gen.Heur.MSIL.Krypt.2_16970cf650

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 Trojan's file once a user opens a drive's folder in Windows Explorer.

Process activity

The Trojan creates the following process(es):

%original file name%.exe:1700

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

THAZ.exe:644
svchost.exe:224

Mutexes

The following mutexes were created/opened:No objects were found.

File activity

The process THAZ.exe:644 makes changes in the file system.

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

%Documents and Settings%\%current user%\Local Settings\Temporary Internet Files\Content.IE5\desktop.ini (67 bytes)
%Documents and Settings%\%current user%\Local Settings\History\History.IE5\desktop.ini (159 bytes)
%Documents and Settings%\%current user%\Application Data\Microsoft\Windows\qKau4xtVEnGnoLH.dat (322 bytes)
%Documents and Settings%\%current user%\Local Settings\Temporary Internet Files\Content.IE5\G52VSXQ7\desktop.ini (67 bytes)
%Documents and Settings%\%current user%\Local Settings\Temporary Internet Files\Content.IE5\05AV0XQN\desktop.ini (67 bytes)
%Documents and Settings%\%current user%\Local Settings\Temporary Internet Files\Content.IE5\K5I7S9M7\desktop.ini (67 bytes)
%WinDir%\InstallDir\Server.exe (33 bytes)
%Documents and Settings%\%current user%\Local Settings\Temporary Internet Files\Content.IE5\GXQROL2N\desktop.ini (67 bytes)

The process %original file name%.exe:1700 makes changes in the file system.

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

%Documents and Settings%\%current user%\Local Settings\Temp\THAZ.exe (4708 bytes)

Registry activity

The process THAZ.exe:644 makes changes in the system registry.

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

[HKLM\SOFTWARE\Microsoft\Active Setup\Installed Components\{4Y00NGR4-Q6B1-132Y-8M17-7833RHND1ON6}]
"StubPath" = "%WinDir%\InstallDir\Server.exe restart"

[HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings\Cache\Paths]
"Directory" = "%Documents and Settings%\%current user%\Local Settings\Temporary Internet Files\Content.IE5"

[HKCU\Software\qKau4xtVEnGnoLH]
"ServerName" = "%WinDir%\InstallDir\Server.exe"

[HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings\Cache\Paths\path4]
"CacheLimit" = "65452"
"CachePath" = "%Documents and Settings%\%current user%\Local Settings\Temporary Internet Files\Content.IE5\Cache4"

[HKCU\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Connections]
"SavedLegacySettings" = "3C 00 00 00 1B 00 00 00 01 00 00 00 00 00 00 00"

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

[HKCU\Software\XtremeRAT]
"Mutex" = "qKau4xtVEnGnoLH"

[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\DirectDraw\MostRecentApplication]
"ID" = "708992537"

[HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings\Cache\Paths\path2]
"CachePath" = "%Documents and Settings%\%current user%\Local Settings\Temporary Internet Files\Content.IE5\Cache2"

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

[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"

[HKLM\SOFTWARE\Microsoft\DirectDraw\MostRecentApplication]
"Name" = "THAZ.exe"

[HKLM\System\CurrentControlSet\Hardware Profiles\0001\Software\Microsoft\windows\CurrentVersion\Internet Settings]
"ProxyEnable" = "0"

[HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings\Cache\Paths\path1]
"CacheLimit" = "65452"

[HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings\Cache\Paths\path2]
"CacheLimit" = "65452"

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "FF 95 A7 18 7E 0C F3 B8 3B A7 3A 0A 70 56 77 EE"

[HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings\Cache\Paths\path1]
"CachePath" = "%Documents and Settings%\%current user%\Local Settings\Temporary Internet Files\Content.IE5\Cache1"

[HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings\Cache\Paths\path3]
"CacheLimit" = "65452"

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

[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"

[HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings\Cache\Paths\path3]
"CachePath" = "%Documents and Settings%\%current user%\Local Settings\Temporary Internet Files\Content.IE5\Cache3"

[HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings\Cache\Paths]
"Paths" = "4"

[HKCU\Software\qKau4xtVEnGnoLH]
"ServerStarted" = "19/06/2016 14:40:21"

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

The Trojan 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"

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

[HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run]
"HKLM" = "%WinDir%\InstallDir\Server.exe"

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

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

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

"ProxyBypass" = "1"

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

[HKCU\Software\Microsoft\Windows\CurrentVersion\Run]
"HKCU" = "%WinDir%\InstallDir\Server.exe"

Proxy settings are disabled:

[HKCU\Software\Microsoft\Windows\CurrentVersion\Internet Settings]
"ProxyEnable" = "0"

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

[HKCU\Software\Microsoft\Windows\CurrentVersion\Internet Settings]
"AutoConfigURL"
"ProxyServer"
"ProxyOverride"

The process %original file name%.exe:1700 makes changes in the system registry.

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

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "2C 4E A2 5B 53 0A E5 32 BC E4 25 8A FD F2 59 CF"

[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"

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

[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]
"Cache" = "%Documents and Settings%\%current user%\Local Settings\Temporary Internet Files"

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

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

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

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

"IntranetName" = "1"

The Trojan 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"

Dropped PE files

MD5	File path
6ef417e774512e76998d489d31704e0c	c:\Documents and Settings\"%CurrentUserName%"\Local Settings\Temp\THAZ.exe
6ef417e774512e76998d489d31704e0c	c:\WINDOWS\InstallDir\Server.exe

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 Trojan'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:1700
   

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

   %Documents and Settings%\%current user%\Local Settings\Temporary Internet Files\Content.IE5\desktop.ini (67 bytes)
   %Documents and Settings%\%current user%\Local Settings\History\History.IE5\desktop.ini (159 bytes)
   %Documents and Settings%\%current user%\Application Data\Microsoft\Windows\qKau4xtVEnGnoLH.dat (322 bytes)
   %Documents and Settings%\%current user%\Local Settings\Temporary Internet Files\Content.IE5\G52VSXQ7\desktop.ini (67 bytes)
   %Documents and Settings%\%current user%\Local Settings\Temporary Internet Files\Content.IE5\05AV0XQN\desktop.ini (67 bytes)
   %Documents and Settings%\%current user%\Local Settings\Temporary Internet Files\Content.IE5\K5I7S9M7\desktop.ini (67 bytes)
   %WinDir%\InstallDir\Server.exe (33 bytes)
   %Documents and Settings%\%current user%\Local Settings\Temporary Internet Files\Content.IE5\GXQROL2N\desktop.ini (67 bytes)
   %Documents and Settings%\%current user%\Local Settings\Temp\THAZ.exe (4708 bytes)

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

   [HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run]
   "HKLM" = "%WinDir%\InstallDir\Server.exe"
   
   [HKCU\Software\Microsoft\Windows\CurrentVersion\Run]
   "HKCU" = "%WinDir%\InstallDir\Server.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

VersionInfo

Company Name: 1111111111111111111111111111111111111111111111111111
Product Name: 11111111111111111111111111111111111111111111111111
Product Version: 1.0.0.0
Legal Copyright: 11111111111111111111111111111111111111111111111111
Legal Trademarks: 111111111111111111111111111111111111111111111111111111
Original Filename: Stub.exe
Internal Name: Stub.exe
File Version: 1.0.0.0
File Description: 1111111111111111111111111111111111111111111111111
Comments: 1111111111111111111111111111111111111111111111111
Language: English (United States)

Company Name: 1111111111111111111111111111111111111111111111111111Product Name: 11111111111111111111111111111111111111111111111111Product Version: 1.0.0.0Legal Copyright: 11111111111111111111111111111111111111111111111111Legal Trademarks: 111111111111111111111111111111111111111111111111111111Original Filename: Stub.exeInternal Name: Stub.exeFile Version: 1.0.0.0File Description: 1111111111111111111111111111111111111111111111111Comments: 1111111111111111111111111111111111111111111111111Language: English (United States)

PE Sections

Name	Virtual Address	Virtual Size	Raw Size	Entropy	Section MD5
.text	8192	30388	30720	3.97539	99fdad7e802a7d3c21e550cf7f3c8b1e
.sdata	40960	312	512	1.13976	3c815f6e303731d5047e7b654dff6714
.rsrc	49152	217424	217600	4.95266	b2708dc8dca7c55ac6e03a4a9b790d9f
.reloc	270336	12	512	0.056519	89910a00879599755267eab2f6a4fe39

Dropped from:

Downloaded by:

Similar by SSDeep:

Similar by Lavasoft Polymorphic Checker:

Network Activity

URLs

IDS verdicts (Suricata alerts: Emerging Threats ET ruleset)

Traffic

Map

The Trojan connects to the servers at the folowing location(s):

Strings from Dumps

THAZ.exe_644:

`.rsrc

`.rsrc

ServerKeyloggerU

ServerKeyloggerU