Backdoor.Win32.Fynloski_31e2739a0c

Dynamic Analysis

Payload

No specific payload has been found.

Process activity

The Backdoor creates the following process(es):

msdcsc.exe:768
attrib.exe:1120
attrib.exe:1500
notepad.exe:1960
%original file name%.exe:1104
%original file name%.exe:552

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

msdcsc.exe:972
notepad.exe:1524

File activity

The process notepad.exe:1960 makes changes in the file system.

The Backdoor deletes the following file(s):

C:\%original file name%.exe (0 bytes)

The process %original file name%.exe:1104 makes changes in the file system.

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

%Documents and Settings%\%current user%\Desktop\MSDCSC\msdcsc.exe (5441 bytes)
%System%\drivers\etc\hosts (30 bytes)

Registry activity

The process msdcsc.exe:768 makes changes in the system registry.

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

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "B5 DE 2E 6A F5 07 C8 62 94 0D 4B C5 F0 A4 9D 22"

[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 msdcsc.exe:972 makes changes in the system registry.

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

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "43 52 A2 CE B5 10 AD 34 C0 78 B0 42 9B 4D CD A6"

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

[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\Policies\System]
"DisableRegistryTools" = "1"

[HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\MountPoints2\{c155cd75-744b-11e2-8294-806d6172696f}]
"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\{b98117e8-75ca-11e2-81b2-000c293708fb}]
"BaseClass" = "Drive"

User account control (UAC) is disabled:

[HKCU\Software\Microsoft\Windows\CurrentVersion\Policies\System]
"EnableLUA" = "0"

A firewall is disabled:

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

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

[HKCU\Software\Microsoft\Windows\CurrentVersion\Run]
"ãíßÑæÈÏÇÊí.b" = "%Documents and Settings%\%current user%\Desktop\MSDCSC\msdcsc.exe"

Firewall notifications are enabled:

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

Task Manager is disabled:

[HKCU\Software\Microsoft\Windows\CurrentVersion\Policies\System]
"DisableTaskMgr" = "1"

The process attrib.exe:1120 makes changes in the system registry.

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

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "F0 E0 26 56 BE F0 F1 8F F5 AF 99 AA 49 23 50 54"

The process attrib.exe:1500 makes changes in the system registry.

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

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "8F EB 7B 9E 94 CE 0F E1 90 28 1B 70 1C F3 20 F6"

The process notepad.exe:1524 makes changes in the system registry.

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

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "10 50 F6 2E 9D B8 70 7F 7A 48 30 35 CE 7F 43 83"

The process notepad.exe:1960 makes changes in the system registry.

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

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "16 55 F2 25 17 AE A4 C4 0B BA 69 91 55 D5 7D 72"

The process %original file name%.exe:1104 makes changes in the system registry.

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

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "E8 FA E2 AA 0A A9 64 54 FF 1E 34 C0 44 6D F7 EF"

[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\CurrentVersion\Explorer\MountPoints2\{c155cd72-744b-11e2-8294-806d6172696f}]
"BaseClass" = "Drive"

[HKCU\Software\Microsoft\Windows\ShellNoRoam\MUICache\%Documents and Settings%\%current user%\Desktop\MSDCSC]
"msdcsc.exe" = ""

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

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

[HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\MountPoints2\{c155cd75-744b-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]
"Personal" = "%Documents and Settings%\%current user%\My Documents"

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

"IntranetName" = "1"

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

[HKCU\Software\Microsoft\Windows\CurrentVersion\Run]
"ãíßÑæÈÏÇÊí.b" = "%Documents and Settings%\%current user%\Desktop\MSDCSC\msdcsc.exe"

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 adds the reference to itself to be executed when a user logs on:

[HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon]
"UserInit" = "%System%\userinit.exe,%Documents and Settings%\%current user%\Desktop\MSDCSC\msdcsc.exe"

The process %original file name%.exe:552 makes changes in the system registry.

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

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "E5 37 80 D9 6E 9E 2B C7 D6 36 66 90 68 94 31 69"

[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"

Network activity (URLs)

No activity has been detected.

HOSTS file anomalies

The Backdoor modifies "%System%\drivers\etc\hosts" file which is used to translate DNS entries to IP addresses. The modified file is 30 bytes in size. The following strings are added to the hosts file listed below:

yemen123.no-ip.biz	localhost

Rootkit activity

No anomalies have been detected.

Propagation

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):

   msdcsc.exe:768
   attrib.exe:1120
   attrib.exe:1500
   notepad.exe:1960
   %original file name%.exe:1104
   %original file name%.exe:552

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

   %Documents and Settings%\%current user%\Desktop\MSDCSC\msdcsc.exe (5441 bytes)
   %System%\drivers\etc\hosts (30 bytes)

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

   [HKCU\Software\Microsoft\Windows\CurrentVersion\Run]
   "ãíßÑæÈÏÇÊí.b" = "%Documents and Settings%\%current user%\Desktop\MSDCSC\msdcsc.exe"
   
   

5. Remove the references to the Backdoor by modifying the following registry value(s) (How to Work with System Registry):

   [HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon]
   "UserInit" = "%System%\userinit.exe,%Documents and Settings%\%current user%\Desktop\MSDCSC\msdcsc.exe"

6. Restore the original content of the HOSTS file (%System%\drivers\etc\hosts): 127.0.0.1 localhost
   
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