Backdoor.Win32.Fynloski_c42df26d82

by malwarelabrobot on February 24th, 2014 in Malware Descriptions.

Gen:Variant.Kazy.45351 (BitDefender), HEUR:Trojan.Win32.Generic (Kaspersky), Gen:Variant.Kazy.45351 (B) (Emsisoft), Backdoor.MSIL (Ikarus), Gen:Variant.Kazy.45351 (FSecure), Dropper.Msil (AVG), 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
Technical Details
Removal Recommendations

MD5: c42df26d82b85098f2084b3a9c3d0fe9
SHA1: 6bafa4bcc5547c149d2171666fadafd5f61cabc5
SHA256: 88a0bb2918e78e38cc5110f54ca90bbef286e8eb954012057ad8cb0361cfd466
SSDeep: 12288:E 1MNbtLWmIY7dV2b/kRqkMzXU01x/iDLu DuH0Wa6WdwfkXAHrD/g8Wd/0toZ6u:bT0laUh83md2gcGC4WdiOl8F/
Size: 1086976 bytes
File type: EXE
Platform: WIN32
Entropy: Not Packed
PEID: MicrosoftVisualC, NETexecutable, UPolyXv05_v6
Company: no certificate found
Created at: 2014-02-20 05:31:02
Analyzed on: WindowsXP SP3 32-bit


Summary:

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

Payload

No specific payload has been found.

Process activity

The Backdoor creates the following process(es):

%original file name%.exe:456
attrib.exe:416
attrib.exe:508
wscript.exe:1284
notepad.exe:600
%tmp%.exe:1240

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

notepad.exe:220
FacebookUpdate.exe:1764

File activity

The process %original file name%.exe:456 makes changes in the file system.
The Backdoor creates and/or writes to the following file(s):

%Documents and Settings%\%current user%\Application Data\rundll32-.txt (7433 bytes)
%WinDir%\Temp\svchost.exe (7547 bytes)
%Documents and Settings%\%current user%\Application Data\per.bat (124 bytes)
%System%\drivers\etc\hosts (193 bytes)
%Documents and Settings%\%current user%\Application Data\java2.bat (160 bytes)
%Documents and Settings%\%current user%\Local Settings\Temp\%tmp%.exe (1638 bytes)
%Documents and Settings%\%current user%\Application Data\java.bat (53 bytes)
%Documents and Settings%\%current user%\Application Data\invs.vbs (78 bytes)

The Backdoor deletes the following file(s):

%Documents and Settings%\%current user%\Application Data\rundll32-.txt (0 bytes)
%Documents and Settings%\%current user%\Application Data\java.bat (0 bytes)
%Documents and Settings%\%current user%\Application Data\java2.bat (0 bytes)
%Documents and Settings%\%current user%\Application Data\invs.vbs (0 bytes)

The process notepad.exe:600 makes changes in the file system.
The Backdoor deletes the following file(s):

%Documents and Settings%\%current user%\Local Settings\Temp\%tmp%.exe (0 bytes)

The process %tmp%.exe:1240 makes changes in the file system.
The Backdoor creates and/or writes to the following file(s):

%Documents and Settings%\%current user%\Application Data\FacebookUpdate.exe (2105 bytes)

Registry activity

The process %original file name%.exe:456 makes changes in the system registry.
The Backdoor creates and/or sets the following values in system registry:

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "6A 8A 3B D1 6C 53 43 33 F0 18 F1 0C FC 88 CC 61"

[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"

"Desktop" = "%Documents and Settings%\%current user%\Desktop"

[HKCU\Software\Microsoft\Windows\ShellNoRoam\MUICache\%Documents and Settings%\%current user%\Application Data]
"java.bat" = "java"

[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"

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

[HKCU\Software\Microsoft\Windows\ShellNoRoam\MUICache\C:\DOCUME~1\"%CurrentUserName%"\LOCALS~1\Temp]
"%tmp%.exe" = "Remote Service Application"

[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 local web-nodes with no dots which do not refer to any zone to the Intranet Zone:

"UNCAsIntranet" = "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]
"rundll32" = "%Documents and Settings%\%current user%\Application Data\rundll32 .exe"

The process attrib.exe:416 makes changes in the system registry.
The Backdoor creates and/or sets the following values in system registry:

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "0A 4E EC EC 27 0B 45 47 1F 3C 75 1A 2E 16 89 83"

The process attrib.exe:508 makes changes in the system registry.
The Backdoor creates and/or sets the following values in system registry:

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "32 01 8B 71 78 70 74 12 E6 20 95 A0 33 5C B5 84"

The process wscript.exe:1284 makes changes in the system registry.
The Backdoor creates and/or sets the following values in system registry:

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "6B BB 7E E9 A8 C7 3A 84 DB 04 6F D0 1C 24 83 77"

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

[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\ShellNoRoam\MUICache\%Documents and Settings%\%current user%\Application Data]
"java2.bat" = "java2"

[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 urls to the Intranet Zone:

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

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:

"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 process notepad.exe:600 makes changes in the system registry.
The Backdoor creates and/or sets the following values in system registry:

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "34 F6 08 B9 98 44 B4 B2 E5 F5 46 99 6F 0F 79 69"

The process notepad.exe:220 makes changes in the system registry.
The Backdoor creates and/or sets the following values in system registry:

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "30 BD 00 25 10 CE DF D7 BD 48 61 F8 1E 57 AC 20"

The process %tmp%.exe:1240 makes changes in the system registry.
The Backdoor creates and/or sets the following values in system registry:

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "F7 54 77 B9 E3 A1 7E 25 D3 C9 DC A7 16 10 A3 0F"

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

"Desktop" = "%Documents and Settings%\%current user%\Desktop"

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

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

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

[HKCU\Software\Microsoft\Windows\ShellNoRoam\MUICache\%Documents and Settings%\%current user%\Application Data]
"FacebookUpdate.exe" = "Remote Service Application"

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%\Application Data\FacebookUpdate.exe"

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

[HKCU\Software\Microsoft\Windows\CurrentVersion\Internet Settings\ZoneMap]
"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]
"FacebookUpdate.exe" = "%Documents and Settings%\%current user%\Application Data\FacebookUpdate.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 modifies IE settings for security zones to map all web-nodes that bypassing proxy to the Intranet Zone:

"ProxyBypass" = "1"

The process FacebookUpdate.exe:1764 makes changes in the system registry.
The Backdoor creates and/or sets the following values in system registry:

[HKLM\SOFTWARE\Microsoft\Cryptography\RNG]
"Seed" = "B2 21 ED C3 47 91 C7 14 77 D0 AD E4 0A 26 7E B2"

[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"

[HKLM\SOFTWARE\Microsoft\Security Center]
"UpdatesDisableNotify" = "1"

[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"

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]
"FacebookUpdate.exe" = "%Documents and Settings%\%current user%\Application Data\FacebookUpdate.exe"

Antivirus notifications are disabled:

[HKLM\SOFTWARE\Microsoft\Security Center]
"AntiVirusDisableNotify" = "1"

Firewall notifications are enabled:

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

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

127.0.0.1 virustotal.com
127.0.0.1 vscan.novirusthanks.org
127.0.0.1 irusscan.jotti.org
127.0.0.1 virscan.org
127.0.0.1 www.virus-trap.org


Rootkit activity

No anomalies have been detected.

Propagation


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:456
    attrib.exe:416
    attrib.exe:508
    wscript.exe:1284
    notepad.exe:600
    %tmp%.exe:1240

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

    %Documents and Settings%\%current user%\Application Data\rundll32-.txt (7433 bytes)
    %WinDir%\Temp\svchost.exe (7547 bytes)
    %Documents and Settings%\%current user%\Application Data\per.bat (124 bytes)
    %System%\drivers\etc\hosts (193 bytes)
    %Documents and Settings%\%current user%\Application Data\java2.bat (160 bytes)
    %Documents and Settings%\%current user%\Local Settings\Temp\%tmp%.exe (1638 bytes)
    %Documents and Settings%\%current user%\Application Data\java.bat (53 bytes)
    %Documents and Settings%\%current user%\Application Data\invs.vbs (78 bytes)
    %Documents and Settings%\%current user%\Application Data\FacebookUpdate.exe (2105 bytes)

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

    [HKCU\Software\Microsoft\Windows\CurrentVersion\Run]
    "rundll32" = "%Documents and Settings%\%current user%\Application Data\rundll32 .exe"

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

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