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BKDR_PAPRAS.SM

June 08, 2013
 ALIASES:

VirTool:Win32/Obfuscator.JL (Microsoft); Generic FakeAlert!yd (McAfee); Packed.Generic.325 (Symantec); Packed.Win32.Krap.ic (Kaspersky); Backdoor.Win32.Papras.rx (v) (Sunbelt); Packed:W32/MPack.A (FSecure)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

 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.

It deletes itself after execution.

  TECHNICAL DETAILS

File Size:

105,984 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

01 May 2012

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.

Other System Modifications

This backdoor deletes the following files:

  • %User Profile%\Cookies\index.dat
  • %Desktop%.ini
  • %User Profile%\History.IE5\index.dat
  • %User Profile%\MSHist012010121320101220\index.dat
  • %User Profile%\MSHist012010122820101229\index.dat
  • %User Profile%\MSHist012010122920101230\index.dat
  • %User Profile%\MSHist012011010220110103\index.dat
  • %Temporary Internet Files%\Content.IE5\2TPM8950\10[1].htm
  • %Temporary Internet Files%\Content.IE5\2TPM8950\16[1].htm
  • %Temporary Internet Files%\Content.IE5\2TPM8950\192.168.100[1].htm
  • %Temporary Internet Files%\Content.IE5\2TPM8950\192.168.100[2].htm
  • %Temporary Internet Files%\Content.IE5\2TPM8950\192.168.100[3].htm
  • %Temporary Internet Files%\Content.IE5\2TPM8950\192.168.100[4].htm
  • %Temporary Internet Files%\Content.IE5\2TPM8950\bottom_right3[1].png
  • %Temporary Internet Files%\Content.IE5\2TPM8950\box01[1].gif
  • %Temporary Internet Files%\Content.IE5\2TPM8950\box02[1].gif
  • %Temporary Internet Files%\Content.IE5\2TPM8950\box08[1].gif
  • %Temporary Internet Files%\Content.IE5\2TPM8950\desktop.ini
  • %Temporary Internet Files%\Content.IE5\2TPM8950\header00b[1].gif
  • %Temporary Internet Files%\Content.IE5\2TPM8950\jquery-1.4.2.min[1].js
  • %Temporary Internet Files%\Content.IE5\2TPM8950\report_image[1].png
  • %Temporary Internet Files%\Content.IE5\2TPM8950\table_left3[1].png
  • %Temporary Internet Files%\Content.IE5\4H9MXTT9\10[1].htm
  • %Temporary Internet Files%\Content.IE5\4H9MXTT9\192.168.100[1].htm
  • %Temporary Internet Files%\Content.IE5\4H9MXTT9\192.168.100[2].htm
  • %Temporary Internet Files%\Content.IE5\4H9MXTT9\192.168.100[3].htm
  • %Temporary Internet Files%\Content.IE5\4H9MXTT9\192.168.100[4].htm
  • %Temporary Internet Files%\Content.IE5\4H9MXTT9\box07[1].gif
  • %Temporary Internet Files%\Content.IE5\4H9MXTT9\CalendarPopup[1].js
  • %Temporary Internet Files%\Content.IE5\4H9MXTT9\desktop.ini
  • %Temporary Internet Files%\Content.IE5\4H9MXTT9\dropdown[1].jpg
  • %Temporary Internet Files%\Content.IE5\4H9MXTT9\footer00[1].gif
  • %Temporary Internet Files%\Content.IE5\4H9MXTT9\header02[1].jpg
  • %Temporary Internet Files%\Content.IE5\4H9MXTT9\import[1].png
  • %Temporary Internet Files%\Content.IE5\4H9MXTT9\table_bottom3[1].png
  • %Temporary Internet Files%\Content.IE5\4H9MXTT9\table_top3[1].png
  • %Temporary Internet Files%\Content.IE5\4H9MXTT9\transpix[1].gif
  • %Temporary Internet Files%\Content.IE5\desktop.ini
  • %Temporary Internet Files%\Content.IE5\index.dat
  • %Temporary Internet Files%\Content.IE5\SMCZPN4M\10[1].htm
  • %Temporary Internet Files%\Content.IE5\SMCZPN4M\192.168.100[1].htm
  • %Temporary Internet Files%\Content.IE5\SMCZPN4M\192.168.100[2].htm
  • %Temporary Internet Files%\Content.IE5\SMCZPN4M\192.168.100[3].htm
  • %Temporary Internet Files%\Content.IE5\SMCZPN4M\192.168.100[4].htm
  • %Temporary Internet Files%\Content.IE5\SMCZPN4M\background[1].gif
  • %Temporary Internet Files%\Content.IE5\SMCZPN4M\box03[1].gif
  • %Temporary Internet Files%\Content.IE5\SMCZPN4M\box04[1].gif
  • %Temporary Internet Files%\Content.IE5\SMCZPN4M\box06[1].gif
  • %Temporary Internet Files%\Content.IE5\SMCZPN4M\config[1].gif
  • %Temporary Internet Files%\Content.IE5\SMCZPN4M\desktop.ini
  • %Temporary Internet Files%\Content.IE5\SMCZPN4M\edit_icon_thumb[1].png
  • %Temporary Internet Files%\Content.IE5\SMCZPN4M\jquery-ui-1.8.custom.min[1].js
  • %Temporary Internet Files%\Content.IE5\SMCZPN4M\sandbox[1].css
  • %Temporary Internet Files%\Content.IE5\SMCZPN4M\top_right3[1].png
  • %Temporary Internet Files%\Content.IE5\X9QQH2D9\192.168.100[1].htm
  • %Temporary Internet Files%\Content.IE5\X9QQH2D9\192.168.100[2].htm
  • %Temporary Internet Files%\Content.IE5\X9QQH2D9\192.168.100[3].htm
  • %Temporary Internet Files%\Content.IE5\X9QQH2D9\192.168.100[4].htm
  • %Temporary Internet Files%\Content.IE5\X9QQH2D9\192.168.100[5].htm
  • %Temporary Internet Files%\Content.IE5\X9QQH2D9\bottom_left3[1].png
  • %Temporary Internet Files%\Content.IE5\X9QQH2D9\box09[1].gif
  • %Temporary Internet Files%\Content.IE5\X9QQH2D9\delete_icon_thumb[1].png
  • %Temporary Internet Files%\Content.IE5\X9QQH2D9\desktop.ini
  • %Temporary Internet Files%\Content.IE5\X9QQH2D9\jquery.jeditable.mini[1].js
  • %Temporary Internet Files%\Content.IE5\X9QQH2D9\overlib[1].js
  • %Temporary Internet Files%\Content.IE5\X9QQH2D9\sunbeltlabs_logo[1].jpg
  • %Temporary Internet Files%\Content.IE5\X9QQH2D9\table_right3[1].png
  • %Temporary Internet Files%\Content.IE5\X9QQH2D9\top_left3[1].png
  • %Temporary Internet Files%\Content.IE5\X9QQH2D9\users[1].png
  • %Temporary Internet Files%\desktop.ini

(Note: %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.. %Desktop% is the current user's desktop, which is usually C:\Documents and Settings\{User Name}\Desktop on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\Desktop on Windows Vista and 7.. %Temporary Internet Files% is the Temporary Internet Files folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temporary Internet Files on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local\Microsoft\Windows\Temporary Internet Files on Windows Vista and 7.)

It deletes the following folders:

  • %User Profile%\History.IE5\MSHist012010121320101220
  • %User Profile%\History.IE5\MSHist012010122820101229
  • %User Profile%\History.IE5\MSHist012010122920101230
  • %User Profile%\History.IE5\MSHist012011010220110103
  • %User Profile%\History\History.IE5
  • %Temporary Internet Files%\Content.IE5\2TPM8950
  • %Temporary Internet Files%\Content.IE5\4H9MXTT9
  • %Temporary Internet Files%\Content.IE5\SMCZPN4M
  • %Temporary Internet Files%\Content.IE5\X9QQH2D9
  • %Temporary Internet Files%\Content.IE5

(Note: %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.. %Temporary Internet Files% is the Temporary Internet Files folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temporary Internet Files on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local\Microsoft\Windows\Temporary Internet Files on Windows Vista and 7.)

It adds the following registry keys:

HKEY_LOCAL_MACHINE\System\CurrentControlSet\
Control\Session Manager\AppCertDlls

HKEY_CURRENT_USER\SOFTWARE\AppDataLow\
{c30a2ad0-ffef-2c82-04f9-783dd6936a77}

HKEY_CURRENT_USER\{09c5c506-58ad-6228-9a67-6e8bdc31d0f5}

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Control\Session Manager\AppCertDlls
chknrcp = "%System%\cscrsass.dll"

HKEY_CURRENT_USER\Software\AppDataLow\
{c30a2ad0-ffef-2c82-04f9-783dd6936a77}
k1 = "35d569"

HKEY_CURRENT_USER\Software\AppDataLow\
{c30a2ad0-ffef-2c82-04f9-783dd6936a77}
k2 = "4645423a"

HKEY_CURRENT_USER\Software\AppDataLow\
{c30a2ad0-ffef-2c82-04f9-783dd6936a77}
Version = "c11"

Dropping Routine

This backdoor drops the following files:

  • %System Root%\42671.bat

(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)

Other Details

This backdoor deletes itself after execution.

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine:

9.200

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_LOCAL_MACHINE\System\CurrentControlSet\Control\Session Manager
    • AppCertDlls
  • In HKEY_CURRENT_USER\SOFTWARE\AppDataLow
    • {c30a2ad0-ffef-2c82-04f9-783dd6936a77}
  • In HKEY_CURRENT_USER
    • {09c5c506-58ad-6228-9a67-6e8bdc31d0f5}

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\Control\Session Manager\AppCertDlls
    • chknrcp = "%System%\cscrsass.dll"
  • In HKEY_CURRENT_USER\Software\AppDataLow\{c30a2ad0-ffef-2c82-04f9-783dd6936a77}
    • k1 = "35d569"
  • In HKEY_CURRENT_USER\Software\AppDataLow\{c30a2ad0-ffef-2c82-04f9-783dd6936a77}
    • k2 = "4645423a"
  • In HKEY_CURRENT_USER\Software\AppDataLow\{c30a2ad0-ffef-2c82-04f9-783dd6936a77}
    • Version = "c11"

Step 4

Search and delete this file

[ Learn More ]
There may be some files 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.
  • %System Root%\42671.bat

Step 5

Scan your computer with your Trend Micro product to delete files detected as BKDR_PAPRAS.SM. 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 6

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.

  • %User Profile%\Cookies\index.dat
  • %Desktop%.ini
  • %User Profile%\History.IE5\index.dat
  • %User Profile%\MSHist012010121320101220\index.dat
  • %User Profile%\MSHist012010122820101229\index.dat
  • %User Profile%\MSHist012010122920101230\index.dat
  • %User Profile%\MSHist012011010220110103\index.dat
  • %Temporary Internet Files%\Content.IE5\2TPM8950\10[1].htm
  • %Temporary Internet Files%\Content.IE5\2TPM8950\16[1].htm
  • %Temporary Internet Files%\Content.IE5\2TPM8950\192.168.100[1].htm
  • %Temporary Internet Files%\Content.IE5\2TPM8950\192.168.100[2].htm
  • %Temporary Internet Files%\Content.IE5\2TPM8950\192.168.100[3].htm
  • %Temporary Internet Files%\Content.IE5\2TPM8950\192.168.100[4].htm
  • %Temporary Internet Files%\Content.IE5\2TPM8950\bottom_right3[1].png
  • %Temporary Internet Files%\Content.IE5\2TPM8950\box01[1].gif
  • %Temporary Internet Files%\Content.IE5\2TPM8950\box02[1].gif
  • %Temporary Internet Files%\Content.IE5\2TPM8950\box08[1].gif
  • %Temporary Internet Files%\Content.IE5\2TPM8950\desktop.ini
  • %Temporary Internet Files%\Content.IE5\2TPM8950\header00b[1].gif
  • %Temporary Internet Files%\Content.IE5\2TPM8950\jquery-1.4.2.min[1].js
  • %Temporary Internet Files%\Content.IE5\2TPM8950\report_image[1].png
  • %Temporary Internet Files%\Content.IE5\2TPM8950\table_left3[1].png
  • %Temporary Internet Files%\Content.IE5\4H9MXTT9\10[1].htm
  • %Temporary Internet Files%\Content.IE5\4H9MXTT9\192.168.100[1].htm
  • %Temporary Internet Files%\Content.IE5\4H9MXTT9\192.168.100[2].htm
  • %Temporary Internet Files%\Content.IE5\4H9MXTT9\192.168.100[3].htm
  • %Temporary Internet Files%\Content.IE5\4H9MXTT9\192.168.100[4].htm
  • %Temporary Internet Files%\Content.IE5\4H9MXTT9\box07[1].gif
  • %Temporary Internet Files%\Content.IE5\4H9MXTT9\CalendarPopup[1].js
  • %Temporary Internet Files%\Content.IE5\4H9MXTT9\desktop.ini
  • %Temporary Internet Files%\Content.IE5\4H9MXTT9\dropdown[1].jpg
  • %Temporary Internet Files%\Content.IE5\4H9MXTT9\footer00[1].gif
  • %Temporary Internet Files%\Content.IE5\4H9MXTT9\header02[1].jpg
  • %Temporary Internet Files%\Content.IE5\4H9MXTT9\import[1].png
  • %Temporary Internet Files%\Content.IE5\4H9MXTT9\table_bottom3[1].png
  • %Temporary Internet Files%\Content.IE5\4H9MXTT9\table_top3[1].png
  • %Temporary Internet Files%\Content.IE5\4H9MXTT9\transpix[1].gif
  • %Temporary Internet Files%\Content.IE5\desktop.ini
  • %Temporary Internet Files%\Content.IE5\index.dat
  • %Temporary Internet Files%\Content.IE5\SMCZPN4M\10[1].htm
  • %Temporary Internet Files%\Content.IE5\SMCZPN4M\192.168.100[1].htm
  • %Temporary Internet Files%\Content.IE5\SMCZPN4M\192.168.100[2].htm
  • %Temporary Internet Files%\Content.IE5\SMCZPN4M\192.168.100[3].htm
  • %Temporary Internet Files%\Content.IE5\SMCZPN4M\192.168.100[4].htm
  • %Temporary Internet Files%\Content.IE5\SMCZPN4M\background[1].gif
  • %Temporary Internet Files%\Content.IE5\SMCZPN4M\box03[1].gif
  • %Temporary Internet Files%\Content.IE5\SMCZPN4M\box04[1].gif
  • %Temporary Internet Files%\Content.IE5\SMCZPN4M\box06[1].gif
  • %Temporary Internet Files%\Content.IE5\SMCZPN4M\config[1].gif
  • %Temporary Internet Files%\Content.IE5\SMCZPN4M\desktop.ini
  • %Temporary Internet Files%\Content.IE5\SMCZPN4M\edit_icon_thumb[1].png
  • %Temporary Internet Files%\Content.IE5\SMCZPN4M\jquery-ui-1.8.custom.min[1].js
  • %Temporary Internet Files%\Content.IE5\SMCZPN4M\sandbox[1].css
  • %Temporary Internet Files%\Content.IE5\SMCZPN4M\top_right3[1].png
  • %Temporary Internet Files%\Content.IE5\X9QQH2D9\192.168.100[1].htm
  • %Temporary Internet Files%\Content.IE5\X9QQH2D9\192.168.100[2].htm
  • %Temporary Internet Files%\Content.IE5\X9QQH2D9\192.168.100[3].htm
  • %Temporary Internet Files%\Content.IE5\X9QQH2D9\192.168.100[4].htm
  • %Temporary Internet Files%\Content.IE5\X9QQH2D9\192.168.100[5].htm
  • %Temporary Internet Files%\Content.IE5\X9QQH2D9\bottom_left3[1].png
  • %Temporary Internet Files%\Content.IE5\X9QQH2D9\box09[1].gif
  • %Temporary Internet Files%\Content.IE5\X9QQH2D9\delete_icon_thumb[1].png
  • %Temporary Internet Files%\Content.IE5\X9QQH2D9\desktop.ini
  • %Temporary Internet Files%\Content.IE5\X9QQH2D9\jquery.jeditable.mini[1].js
  • %Temporary Internet Files%\Content.IE5\X9QQH2D9\overlib[1].js
  • %Temporary Internet Files%\Content.IE5\X9QQH2D9\sunbeltlabs_logo[1].jpg
  • %Temporary Internet Files%\Content.IE5\X9QQH2D9\table_right3[1].png
  • %Temporary Internet Files%\Content.IE5\X9QQH2D9\top_left3[1].png
  • %Temporary Internet Files%\Content.IE5\X9QQH2D9\users[1].png
  • %Temporary Internet Files%\desktop.ini


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