BKDR_NECURS.XXTX

September 08, 2015
 PLATFORM:

Windows

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

This backdoor arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

  TECHNICAL DETAILS

File Size:

130,304 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

08 Sep 2015

Arrival Details

This backdoor arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

Installation

This backdoor drops the following copies of itself into the affected system:

  • %Windows%\Installer\{2D0AF8C1-0998-48E2-5AD1-46DF39CD1069}\syshost.exe

(Note: %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.)

It creates the following folders:

  • %Windows%\Installer\{2D0AF8C1-0998-48E2-5AD1-46DF39CD1069}

(Note: %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.)

Other System Modifications

This backdoor deletes the following files:

  • {malware path and file name}.tmp
  • %Windows%\Installer\{2D0AF8C1-0998-48E2-5AD1-46DF39CD1069}\syshost.exe:Zone.Identifier
  • %Windows%\Installer\{2D0AF8C1-0998-48E2-5AD1-46DF39CD1069}\syshost.exe.tmp
  • %User Temp%\70eb720f.tmp

(Note: %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.. %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)

It adds the following registry keys:

HKEY_CURRENT_USER\Software\WinRAR

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\syshost32
f259adc725e5da46 = "{random values}"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\syshost32
68a49afff60febcd = "{random values}"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\syshost32
1d15213fe659428 = "{random values}"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\syshost32
5f551a404b4e78da = "{random values}"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\syshost32
3777bf2f6573c1b6 = "{random values}"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\syshost32
c5a9bb6e54da971d = "{random values}"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\syshost32
7c214454e900b0d6 = "{random values}"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\syshost32
c6ebd988aedaca7f = "{random values}"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\SharedAccess\Parameters\
FirewallPolicy\DomainProfile
EnableFirewall = "0"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\SharedAccess\Parameters\
FirewallPolicy\DomainProfile
DoNotAllowExceptions = "0"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile
EnableFirewall = "0"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile
DoNotAllowExceptions = "0"

HKEY_CURRENT_USER\Software\WinRAR
HWID = "{random values}"

HKEY_CURRENT_USER\Software\WinRAR
Client Hash = "{random values}"

Dropping Routine

This backdoor drops the following files:

  • %Temp%\a6b5518b-97a3-f0e0-8be5-5e1f98b174b4.tmp
  • %Temp%\519b7ad3-e4ad-7660-3055-261eff290102.tmp
  • %Temp%\d6e86eb6-852d-7d21-15a7-74ffffb10fdb.tmp
  • %Temp%\f70b61a6-0fc3-1391-71c9-81fe6017f4f6.tmp
  • %Temp%\e908fc1b-c8a1-adc2-a141-95bb78ff66d8.tmp
  • %System%\drivers\217c4.sys
  • %System%\drivers\22531.sys
  • %System%\drivers\226e7.sys
  • %System%\drivers\2286d.sys
  • %System%\drivers\22a13.sys
  • %System%\drivers\22bb9.sys
  • %System%\drivers\22e49.sys
  • %System%\drivers\2351f.sys
  • %System%\drivers\237fe.sys
  • %System%\drivers\24665.sys
  • %System%\drivers\24888.sys
  • %System%\drivers\24abb.sys
  • %System%\drivers\2572e.sys
  • %System%\drivers\257ca.sys
  • %System%\drivers\25867.sys
  • %System%\drivers\25922.sys
  • %System%\drivers\25b16.sys
  • %System%\drivers\25bb2.sys
  • %System%\drivers\25c3f.sys
  • %System%\drivers\25cdb.sys
  • %System%\drivers\25d78.sys
  • %System%\drivers\25e04.sys
  • %System%\drivers\25ea0.sys
  • %System%\drivers\25f4c.sys
  • %System%\drivers\25fd9.sys
  • %System%\drivers\26075.sys
  • %System%\drivers\26102.sys
  • %System%\drivers\261ae.sys
  • %System%\drivers\2624a.sys
  • %System%\drivers\263a2.sys
  • %System%\drivers\266ed.sys
  • %System%\drivers\26836.sys
  • %System%\drivers\268c2.sys
  • %System%\drivers\2695e.sys
  • %System%\drivers\26aa7.sys
  • %System%\drivers\26b72.sys
  • %System%\drivers\26caa.sys
  • %System%\drivers\26d46.sys
  • %System%\drivers\26f98.sys
  • %System%\drivers\27034.sys
  • %System%\drivers\270c1.sys
  • %System%\drivers\2715d.sys
  • %System%\drivers\271ea.sys
  • %System%\drivers\27342.sys
  • %System%\drivers\2748a.sys
  • %System%\drivers\275d2.sys
  • %System%\drivers\2772a.sys
  • %System%\drivers\27872.sys
  • %System%\drivers\279ba.sys
  • %System%\drivers\27b02.sys
  • %System%\drivers\27c5a.sys
  • %System%\drivers\27da2.sys
  • %System%\drivers\27efa.sys
  • %System%\drivers\28042.sys
  • %System%\drivers\2819a.sys
  • %System%\drivers\28301.sys
  • %System%\drivers\28459.sys
  • %System%\drivers\285a1.sys
  • %System%\drivers\28718.sys
  • %System%\drivers\28860.sys
  • %System%\drivers\289a8.sys
  • %System%\drivers\29800.sys
  • %System%\drivers\29a42.sys
  • %System%\drivers\29c84.sys
  • %System%\drivers\29eb7.sys
  • %System%\drivers\2a0e9.sys
  • %System%\drivers\2a32b.sys
  • %System%\drivers\2a55e.sys
  • %System%\drivers\2a781.sys
  • %System%\drivers\2b3e5.sys
  • %System%\drivers\2b481.sys
  • %System%\drivers\2b4fe.sys
  • %System%\drivers\2b59a.sys
  • %System%\drivers\2b636.sys
  • %System%\drivers\2b6c3.sys

(Note: %Temp% is the Windows temporary folder, where it usually is C:\Windows\Temp on all Windows operating system versions.. %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)

Other Details

This backdoor connects to the following possibly malicious URL:

  • http://{BLOCKED}.26.254
  • {BLOCKED}2.74.22
  • {BLOCKED}5.196.241
  • {BLOCKED}134.162
  • {BLOCKED}6.103.130
  • {BLOCKED}144.130
  • {BLOCKED}.67.43
  • {BLOCKED}70.106
  • {BLOCKED}.210.46
  • {BLOCKED}.252.180
  • {BLOCKED}6.43.70
  • {BLOCKED}8
  • {BLOCKED}.166.26
  • {BLOCKED}103.95
  • {BLOCKED}.0.32
  • {BLOCKED}4.159.123
  • {BLOCKED}6.119.148

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine:

9.750

Step 1

Before doing any scans, Windows XP, Windows Vista, and Windows 7 users must disable System Restore to allow full scanning of their computers.

Step 2

Delete this registry key

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.

  • In HKEY_CURRENT_USER\Software
    • WinRAR

Step 3

Delete this registry value

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.

  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\syshost32
    • f259adc725e5da46 = "{random values}"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\syshost32
    • 68a49afff60febcd = "{random values}"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\syshost32
    • 1d15213fe659428 = "{random values}"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\syshost32
    • 5f551a404b4e78da = "{random values}"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\syshost32
    • 3777bf2f6573c1b6 = "{random values}"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\syshost32
    • c5a9bb6e54da971d = "{random values}"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\syshost32
    • 7c214454e900b0d6 = "{random values}"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\syshost32
    • c6ebd988aedaca7f = "{random values}"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\SharedAccess\Parameters\FirewallPolicy\DomainProfile
    • EnableFirewall = "0"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\SharedAccess\Parameters\FirewallPolicy\DomainProfile
    • DoNotAllowExceptions = "0"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile
    • EnableFirewall = "0"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile
    • DoNotAllowExceptions = "0"
  • In HKEY_CURRENT_USER\Software\WinRAR
    • HWID = "{random values}"
  • In HKEY_CURRENT_USER\Software\WinRAR
    • Client Hash = "{random values}"

Step 4

Search and delete these components

[ Learn More ]
There may be some components that are hidden. Please make sure you check the Search Hidden Files and Folders checkbox in the "More advanced options" option to include all hidden files and folders in the search result.
  • %Temp%\a6b5518b-97a3-f0e0-8be5-5e1f98b174b4.tmp
  • %Temp%\519b7ad3-e4ad-7660-3055-261eff290102.tmp
  • %Temp%\d6e86eb6-852d-7d21-15a7-74ffffb10fdb.tmp
  • %Temp%\f70b61a6-0fc3-1391-71c9-81fe6017f4f6.tmp
  • %Temp%\e908fc1b-c8a1-adc2-a141-95bb78ff66d8.tmp
  • %System%\drivers\217c4.sys
  • %System%\drivers\22531.sys
  • %System%\drivers\226e7.sys
  • %System%\drivers\2286d.sys
  • %System%\drivers\22a13.sys
  • %System%\drivers\22bb9.sys
  • %System%\drivers\22e49.sys
  • %System%\drivers\2351f.sys
  • %System%\drivers\237fe.sys
  • %System%\drivers\24665.sys
  • %System%\drivers\24888.sys
  • %System%\drivers\24abb.sys
  • %System%\drivers\2572e.sys
  • %System%\drivers\257ca.sys
  • %System%\drivers\25867.sys
  • %System%\drivers\25922.sys
  • %System%\drivers\25b16.sys
  • %System%\drivers\25bb2.sys
  • %System%\drivers\25c3f.sys
  • %System%\drivers\25cdb.sys
  • %System%\drivers\25d78.sys
  • %System%\drivers\25e04.sys
  • %System%\drivers\25ea0.sys
  • %System%\drivers\25f4c.sys
  • %System%\drivers\25fd9.sys
  • %System%\drivers\26075.sys
  • %System%\drivers\26102.sys
  • %System%\drivers\261ae.sys
  • %System%\drivers\2624a.sys
  • %System%\drivers\263a2.sys
  • %System%\drivers\266ed.sys
  • %System%\drivers\26836.sys
  • %System%\drivers\268c2.sys
  • %System%\drivers\2695e.sys
  • %System%\drivers\26aa7.sys
  • %System%\drivers\26b72.sys
  • %System%\drivers\26caa.sys
  • %System%\drivers\26d46.sys
  • %System%\drivers\26f98.sys
  • %System%\drivers\27034.sys
  • %System%\drivers\270c1.sys
  • %System%\drivers\2715d.sys
  • %System%\drivers\271ea.sys
  • %System%\drivers\27342.sys
  • %System%\drivers\2748a.sys
  • %System%\drivers\275d2.sys
  • %System%\drivers\2772a.sys
  • %System%\drivers\27872.sys
  • %System%\drivers\279ba.sys
  • %System%\drivers\27b02.sys
  • %System%\drivers\27c5a.sys
  • %System%\drivers\27da2.sys
  • %System%\drivers\27efa.sys
  • %System%\drivers\28042.sys
  • %System%\drivers\2819a.sys
  • %System%\drivers\28301.sys
  • %System%\drivers\28459.sys
  • %System%\drivers\285a1.sys
  • %System%\drivers\28718.sys
  • %System%\drivers\28860.sys
  • %System%\drivers\289a8.sys
  • %System%\drivers\29800.sys
  • %System%\drivers\29a42.sys
  • %System%\drivers\29c84.sys
  • %System%\drivers\29eb7.sys
  • %System%\drivers\2a0e9.sys
  • %System%\drivers\2a32b.sys
  • %System%\drivers\2a55e.sys
  • %System%\drivers\2a781.sys
  • %System%\drivers\2b3e5.sys
  • %System%\drivers\2b481.sys
  • %System%\drivers\2b4fe.sys
  • %System%\drivers\2b59a.sys
  • %System%\drivers\2b636.sys
  • %System%\drivers\2b6c3.sys

Step 5

Search and delete this folder

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden folders in the search result.
  • %Windows%\Installer\{2D0AF8C1-0998-48E2-5AD1-46DF39CD1069}

Step 6

Scan your computer with your Trend Micro product to delete files detected as BKDR_NECURS.XXTX. If the detected files have already been cleaned, deleted, or quarantined by your Trend Micro product, no further step is required. You may opt to simply delete the quarantined files. Please check this Knowledge Base page for more information.

Step 7

Restore this file from backup only Microsoft-related files will be restored. If this malware/grayware also deleted files related to programs that are not from Microsoft, please reinstall those programs on you computer again.

  • {malware path and file name}.tmp
  • %Windows%\Installer\{2D0AF8C1-0998-48E2-5AD1-46DF39CD1069}\syshost.exe:Zone.Identifier
  • %Windows%\Installer\{2D0AF8C1-0998-48E2-5AD1-46DF39CD1069}\syshost.exe.tmp
  • %User Temp%\70eb720f.tmp


Did this description help? Tell us how we did.