Backdoor.Win32.Farfli_7cc14ad170

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

Process activity

The Backdoor creates the following process(es):

suLjyXabeeG6r3PMTNOF.exe:1480
%original file name%.exe:396

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

svchost.exe:544
iexplore.exe:1228

Mutexes

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

File activity

The process suLjyXabeeG6r3PMTNOF.exe:1480 makes changes in the file system.

The Backdoor deletes the following file(s):

%Documents and Settings%\%current user%\Local Settings\Temp\x.html (0 bytes)

The process %original file name%.exe:396 makes changes in the file system.

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

%WinDir%\Microsoft.NET\Framework\v2.0.50727\CONFIG\enterprisesec.config.cch.new (10036 bytes)
%WinDir%\Microsoft.NET\Framework\v2.0.50727\CONFIG\security.config.cch.new (10036 bytes)
%WinDir%\suLjyXabeeG6r3PMTNOF.exe (33 bytes)

Registry activity

The process suLjyXabeeG6r3PMTNOF.exe:1480 makes changes in the system registry.

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

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "A0 C6 AB 3C 52 77 E1 AC D7 A7 55 61 E5 BD 0A 24"

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

[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"

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

[HKCU\Software\XtremeRAT]
"Mutex" = "--((Mutex))--"

The process %original file name%.exe:396 makes changes in the system registry.

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

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "D8 FB DE CA 32 26 DA 9F B6 90 B6 48 FC 53 D7 8C"

[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\%WinDir%]
"suLjyXabeeG6r3PMTNOF.exe" = "suLjyXabeeG6r3PMTNOF"

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

"IntranetName" = "1"

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

"ProxyBypass" = "1"

Dropped PE files

MD5	File path
f60755947f262f10fb4da99cb13dd94a	c:\WINDOWS\InstallDir\Server.exe
f60755947f262f10fb4da99cb13dd94a	c:\WINDOWS\suLjyXabeeG6r3PMTNOF.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 Backdoor'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):

   suLjyXabeeG6r3PMTNOF.exe:1480
   %original file name%.exe:396
   

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

   %WinDir%\Microsoft.NET\Framework\v2.0.50727\CONFIG\enterprisesec.config.cch.new (10036 bytes)
   %WinDir%\Microsoft.NET\Framework\v2.0.50727\CONFIG\security.config.cch.new (10036 bytes)
   %WinDir%\suLjyXabeeG6r3PMTNOF.exe (33 bytes)

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

*Manual removal may cause unexpected system behaviour and should be performed at your own risk.

Static Analysis

VersionInfo

Company Name:
Product Name:
Product Version: 0.0.0.0
Legal Copyright:
Legal Trademarks:
Original Filename: server.exe
Internal Name: server.exe
File Version: 0.0.0.0
File Description:
Comments:
Language: Language Neutral

Company Name: Product Name: Product Version: 0.0.0.0Legal Copyright: Legal Trademarks: Original Filename: server.exeInternal Name: server.exeFile Version: 0.0.0.0File Description: Comments: Language: Language Neutral

PE Sections

Name	Virtual Address	Virtual Size	Raw Size	Entropy	Section MD5
.text	8192	3945895	3945984	3.78813	4334361d5c02f597345b60e98dc547c7
.rsrc	3956736	664	1024	1.47862	63f525e3b6792c692f08ee76bd0eb762
.reloc	3964928	12	512	0.070639	d152222fe347b1b0f9e0adf7f3008a4f

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 Backdoor connects to the servers at the folowing location(s):

Strings from Dumps

svchost.exe_544:

.text

.text

`.data

`.data

.rsrc

.rsrc

ADVAPI32.dll

ADVAPI32.dll

KERNEL32.dll

KERNEL32.dll

NTDLL.DLL

NTDLL.DLL

RPCRT4.dll

RPCRT4.dll

NETAPI32.dll

NETAPI32.dll

ole32.dll

ole32.dll

ntdll.dll

ntdll.dll

RegCloseKey

RegCloseKey

RegOpenKeyExW

RegOpenKeyExW

GetProcessHeap

GetProcessHeap

NtOpenKey

NtOpenKey

svchost.pdb

svchost.pdb

\PIPE\

\PIPE\

Software\Microsoft\Windows NT\CurrentVersion\Svchost

Software\Microsoft\Windows NT\CurrentVersion\Svchost

\Registry\Machine\System\CurrentControlSet\Control\SecurePipeServers\

\Registry\Machine\System\CurrentControlSet\Control\SecurePipeServers\

5.1.2600.5512 (xpsp.080413-2111)

5.1.2600.5512 (xpsp.080413-2111)

svchost.exe

svchost.exe

Windows

Windows

Operating System

Operating System

5.1.2600.5512

5.1.2600.5512

svchost.exe_544_rwx_10000000_0004D000:

`.rsrc

`.rsrc

ServerKeyloggerU

ServerKeyloggerU