WORM_OSCHA.A


 ALIASES:

Worm:MSIL/Wisbipuf.B (Microsoft); RDN/Generic.dx!drp (McAfee); Trojan.Gen (Symantec); Worm.MSIL.Agent.aqk (Kaspersky); Trojan.Win32.Generic!BT (Sunbelt); Trojan horse MSIL7.CFJE (AVG)

 PLATFORM:

Windows

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

This worm 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:

97,792 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

02 Jun 2015

Arrival Details

This worm 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 worm deletes the following files:

  • %User Temp%\elpy7x8d.pdb
  • %User Temp%\nx4-vjfb.pdb
  • %User Temp%\kk3p48r4.pdb
  • %User Temp%\ijghj7er.pdb
  • %User Temp%\p7ntvpoa.pdb
  • %User Temp%\rttbogj5.pdb
  • %User Temp%\6igckax8.pdb
  • %User Temp%\p-vdd44k.pdb
  • %User Temp%\jtfowidd.pdb
  • %System Root%\??zb.pdb
  • %User Temp%\vbc7.tmp
  • %System Root%\?f???.pdb
  • %User Temp%\vbc18.tmp
  • %System Root%\B?f??KF.pdb
  • %User Temp%\vbc29.tmp
  • %System Root%\?Y?s??.pdb
  • %User Temp%\vbc3A.tmp
  • %System Root%\W?XkHfd.pdb
  • %User Temp%\vbc4B.tmp

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

It modifies the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
HideFileExt = "1"

(Note: The default value data of the said registry entry is 1.)

Dropping Routine

This worm drops the following files:

  • %User Temp%\elpy7x8d.tmp
  • %User Temp%\elpy7x8d.0.vb
  • %User Temp%\elpy7x8d.cmdline
  • %User Temp%\elpy7x8d.out
  • %User Temp%\elpy7x8d.err
  • %User Temp%\nx4-vjfb.tmp
  • %User Temp%\nx4-vjfb.0.vb
  • %User Temp%\nx4-vjfb.cmdline
  • %User Temp%\nx4-vjfb.out
  • %User Temp%\nx4-vjfb.err
  • %User Temp%\kk3p48r4.tmp
  • %User Temp%\kk3p48r4.0.vb
  • %User Temp%\kk3p48r4.cmdline
  • %User Temp%\kk3p48r4.out
  • %User Temp%\kk3p48r4.err
  • %User Temp%\ijghj7er.tmp
  • %User Temp%\ijghj7er.0.vb
  • %User Temp%\ijghj7er.cmdline
  • %User Temp%\ijghj7er.out
  • %User Temp%\ijghj7er.err
  • %User Temp%\p7ntvpoa.tmp
  • %User Temp%\p7ntvpoa.0.vb
  • %User Temp%\p7ntvpoa.cmdline
  • %User Temp%\p7ntvpoa.out
  • %User Temp%\p7ntvpoa.err
  • %User Temp%\rttbogj5.tmp
  • %User Temp%\rttbogj5.0.vb
  • %User Temp%\rttbogj5.cmdline
  • %User Temp%\rttbogj5.out
  • %User Temp%\rttbogj5.err
  • %User Temp%\6igckax8.tmp
  • %User Temp%\6igckax8.0.vb
  • %User Temp%\6igckax8.cmdline
  • %User Temp%\6igckax8.out
  • %User Temp%\6igckax8.err
  • %User Temp%\p-vdd44k.tmp
  • %User Temp%\p-vdd44k.0.vb
  • %User Temp%\p-vdd44k.cmdline
  • %User Temp%\p-vdd44k.out
  • %User Temp%\p-vdd44k.err
  • %User Temp%\jtfowidd.tmp
  • %User Temp%\jtfowidd.0.vb
  • %User Temp%\jtfowidd.cmdline
  • %User Temp%\jtfowidd.out
  • %User Temp%\jtfowidd.err
  • %User Startup%\Interface Setting.lnk
  • %System Root%\??zb.exe
  • %User Temp%\RES9.tmp
  • \?P?z.exe
  • %System Root%\?f???.exe
  • %User Temp%\RES1A.tmp
  • \?xD?G.exe
  • %System Root%\B?f??KF.exe
  • %User Temp%\RES2B.tmp
  • \v?D?.exe
  • %System Root%\?Y?s??.exe
  • %User Temp%\RES3C.tmp
  • \Y?Ff.exe
  • %System Root%\W?XkHfd.exe
  • %User Temp%\RES4D.tmp

(Note: %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.. %User Startup% is the current user's Startup folder, which is usually C:\Windows\Profiles\{user name}\Start Menu\Programs\Startup on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Start Menu\Programs\Startup on Windows NT, and C:\Documents and Settings\{User name}\Start Menu\Programs\Startup.. %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.)

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

Restore these modified registry values

[ Learn More ]

Important:Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this only if you know how to or you can seek your system administrator's help. You may also check out this Microsoft article first before modifying your computer's registry.

  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
    • From: HideFileExt = "1"
      To: HideFileExt = ""1""

Step 3

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.
  • %User Temp%\elpy7x8d.tmp
  • %User Temp%\elpy7x8d.0.vb
  • %User Temp%\elpy7x8d.cmdline
  • %User Temp%\elpy7x8d.out
  • %User Temp%\elpy7x8d.err
  • %User Temp%\nx4-vjfb.tmp
  • %User Temp%\nx4-vjfb.0.vb
  • %User Temp%\nx4-vjfb.cmdline
  • %User Temp%\nx4-vjfb.out
  • %User Temp%\nx4-vjfb.err
  • %User Temp%\kk3p48r4.tmp
  • %User Temp%\kk3p48r4.0.vb
  • %User Temp%\kk3p48r4.cmdline
  • %User Temp%\kk3p48r4.out
  • %User Temp%\kk3p48r4.err
  • %User Temp%\ijghj7er.tmp
  • %User Temp%\ijghj7er.0.vb
  • %User Temp%\ijghj7er.cmdline
  • %User Temp%\ijghj7er.out
  • %User Temp%\ijghj7er.err
  • %User Temp%\p7ntvpoa.tmp
  • %User Temp%\p7ntvpoa.0.vb
  • %User Temp%\p7ntvpoa.cmdline
  • %User Temp%\p7ntvpoa.out
  • %User Temp%\p7ntvpoa.err
  • %User Temp%\rttbogj5.tmp
  • %User Temp%\rttbogj5.0.vb
  • %User Temp%\rttbogj5.cmdline
  • %User Temp%\rttbogj5.out
  • %User Temp%\rttbogj5.err
  • %User Temp%\6igckax8.tmp
  • %User Temp%\6igckax8.0.vb
  • %User Temp%\6igckax8.cmdline
  • %User Temp%\6igckax8.out
  • %User Temp%\6igckax8.err
  • %User Temp%\p-vdd44k.tmp
  • %User Temp%\p-vdd44k.0.vb
  • %User Temp%\p-vdd44k.cmdline
  • %User Temp%\p-vdd44k.out
  • %User Temp%\p-vdd44k.err
  • %User Temp%\jtfowidd.tmp
  • %User Temp%\jtfowidd.0.vb
  • %User Temp%\jtfowidd.cmdline
  • %User Temp%\jtfowidd.out
  • %User Temp%\jtfowidd.err
  • %User Startup%\Interface Setting.lnk
  • %System Root%\??zb.exe
  • %User Temp%\RES9.tmp
  • \?P?z.exe
  • %System Root%\?f???.exe
  • %User Temp%\RES1A.tmp
  • \?xD?G.exe
  • %System Root%\B?f??KF.exe
  • %User Temp%\RES2B.tmp
  • \v?D?.exe
  • %System Root%\?Y?s??.exe
  • %User Temp%\RES3C.tmp
  • \Y?Ff.exe
  • %System Root%\W?XkHfd.exe
  • %User Temp%\RES4D.tmp

Step 4

Scan your computer with your Trend Micro product to delete files detected as WORM_OSCHA.A. 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 5

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 Temp%\elpy7x8d.pdb
  • %User Temp%\nx4-vjfb.pdb
  • %User Temp%\kk3p48r4.pdb
  • %User Temp%\ijghj7er.pdb
  • %User Temp%\p7ntvpoa.pdb
  • %User Temp%\rttbogj5.pdb
  • %User Temp%\6igckax8.pdb
  • %User Temp%\p-vdd44k.pdb
  • %User Temp%\jtfowidd.pdb
  • %System Root%\??zb.pdb
  • %User Temp%\vbc7.tmp
  • %System Root%\?f???.pdb
  • %User Temp%\vbc18.tmp
  • %System Root%\B?f??KF.pdb
  • %User Temp%\vbc29.tmp
  • %System Root%\?Y?s??.pdb
  • %User Temp%\vbc3A.tmp
  • %System Root%\W?XkHfd.pdb
  • %User Temp%\vbc4B.tmp


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