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Backdoor.Win32.Fynloski_c2b5ef548f


Backdoor.Win32.Fynloski.FD, Trojan.Win32.Iconomon.FD, Trojan.Win32.Sasfis.FD, VirTool.Win32.DelfInject.FD, BackdoorFynloski.YR, GenericDownloader.YR, GenericInjector.YR, TrojanDownloaderAndromeda.YR (Lavasoft MAS)Behaviour: Trojan-Downloader, Trojan, Backdoor, VirTool

The description has been automatically generated by Lavasoft Malware Analysis System and it may contain incomplete or inaccurate information.

Summary

MD5: c2b5ef548f0f7386971f24479374e1f6

SHA1: 2213abb9cff63b2e40eb248d071bf7a6bd79bc0b

SHA256: a66822fbbfe053b6c0bb71fc55869e8fed3d0ac5d9ce8535f001397134b31c67

SSDeep: 12288:ulOP5pfMvpwDziv/jToXTgDgJ yRbNlpaUpV1jXOebAjr4g:ulg3fMvp8zevGcgsy/lpJ1SebAjk

Size: 625664 bytes

File type: EXE

Platform: WIN32

Entropy: Packed

PEID: MicrosoftVisualC, NETexecutable, UPolyXv05_v6

Company: SummerSoft

Created at: 2014-02-02 15:26:03

Analyzed on: WindowsXP SP3 32-bit

Summary: Backdoor. Malware that enables a remote control of victim's machine.

Dynamic Analysis

Payload

No specific payload has been found.

Process activity

The Backdoor creates the following process(es):

Reader_sl.exe:1064
reg.exe:572
%original file name%.exe:1960

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

cvtres.exe:1292

File activity

The process cvtres.exe:1292 makes changes in the file system.


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

%System%\drivers\etc\hosts (62 bytes)

The process %original file name%.exe:1960 makes changes in the file system.


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

%Documents and Settings%\%current user%\Application Data\8CIESVeD\aSXudZZqBxs11LBmXqXF8Snfi (79660 bytes)
%Documents and Settings%\%current user%\Application Data\8CIESVeD\n96YlhI.exe.lnk (873 bytes)

Registry activity

The process cvtres.exe:1292 makes changes in the system registry.


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

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "59 F5 7F 10 6B 83 5C E0 F9 F6 AA 4D 22 EB B3 50"

[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"

The process Reader_sl.exe:1064 makes changes in the system registry.


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

[HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\MountPoints2\{c155cd73-744b-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\{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\MountPoints2\{c155cd75-744b-11e2-8294-806d6172696f}]
"BaseClass" = "Drive"

The process reg.exe:572 makes changes in the system registry.


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

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "56 24 50 16 C8 85 1C 53 9E 43 72 B9 ED D0 14 B5"

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]
"CmSjyPtOxC" = "%Documents and Settings%\%current user%\Application Data\8CIESVeD\n96YlhI.exe.lnk"

The process %original file name%.exe:1960 makes changes in the system registry.


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

[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 Start Menu" = "%Documents and Settings%\All Users\Start Menu"

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

[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 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]
"My Pictures" = "%Documents and Settings%\%current user%\My Documents\My Pictures"

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

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

"CommonMusic" = "%Documents and Settings%\All Users\Documents\My Music"

[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]
"CommonPictures" = "%Documents and Settings%\All Users\Documents\My Pictures"

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "29 65 BB AA BE E1 98 46 CB 71 95 A1 FE 71 74 4A"

[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"

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 web-nodes that bypassing proxy to the Intranet Zone:

"ProxyBypass" = "1"

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

"IntranetName" = "1"

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 62 bytes in size. The following strings are added to the hosts file listed below:

127.0.0.1blackhatworld.com
127.0.0.1www.blackhatworld.com


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):

    reg.exe:572
    %original file name%.exe:1960

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

    %System%\drivers\etc\hosts (62 bytes)
    %Documents and Settings%\%current user%\Application Data\8CIESVeD\aSXudZZqBxs11LBmXqXF8Snfi (79660 bytes)
    %Documents and Settings%\%current user%\Application Data\8CIESVeD\n96YlhI.exe.lnk (873 bytes)

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

    [HKCU\Software\Microsoft\Windows\CurrentVersion\Run]
    "CmSjyPtOxC" = "%Documents and Settings%\%current user%\Application Data\8CIESVeD\n96YlhI.exe.lnk"

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