TSPY_ZBOT.YUYADD


 ALIASES:

PWS:Win32/Zbot (Microsoft); Trojan-Spy.Win32.Zbot.kqo (Kaspersky); Troj/MSIL-CVM (Sophos); Win32/Spy.Zbot.ABV trojan (ESET-NOD32)

 PLATFORM:

Windows

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

  • Threat Type: Spyware

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

This spyware arrives as attachment to mass-mailed email messages. It arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It modifies the Internet Explorer Zone Settings.

However, as of this writing, the said sites are inaccessible. It deletes itself after execution.

  TECHNICAL DETAILS

File Size:

165,376 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

03 Jun 2015

Arrival Details

This spyware arrives as attachment to mass-mailed email messages.

It 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 spyware drops the following copies of itself into the affected system:

  • %Application Data%\{random foldername 1}\{random filename 1}.exe

(Note: %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming 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 drops the following files:

  • %Application Data%\{random foldername 2}\{random filename 2}.tmp
  • %Application Data%\{random foldername 2}\{random filename 2}.{random extension}

(Note: %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming 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 creates the following folders:

  • %Application Data%\{random foldername 1}
  • %Application Data%\{random foldername 2}

(Note: %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming 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.)

Other System Modifications

This spyware adds the following registry keys:

HKEY_CURRENT_USER\Software\Microsoft\
{random key 1}

It adds the following registry entries:

HKEY_CURRENT_USER
(Default) = "{hex values}"

HKEY_CURRENT_USER\Software\Microsoft\
{random key 1}
{random 1} = "{hex values}"

HKEY_CURRENT_USER\Software\Microsoft\
{random key 1}
{random 2} = "{hex values}"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings
WarnonBadCertRecving = "0"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings
EnableSPDY3_0 = "0"

Web Browser Home Page and Search Page Modification

This spyware modifies the Internet Explorer Zone Settings.

Other Details

This spyware connects to the following possibly malicious URL:

  • http://{BLOCKED}ecialists.co.nz/claper/server/config.jpg

However, as of this writing, the said sites are inaccessible.

It deletes itself after execution.

  SOLUTION

Minimum Scan Engine:

9.750

FIRST VSAPI PATTERN FILE:

11.678.03

FIRST VSAPI PATTERN DATE:

19 May 2015

VSAPI OPR PATTERN File:

11.679.00

VSAPI OPR PATTERN Date:

20 May 2015

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

Note that not all files, folders, and registry keys and entries are installed on your computer during this malware's/spyware's/grayware's execution. This may be due to incomplete installation or other operating system conditions. If you do not find the same files/folders/registry information, please proceed to the next step.

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_CURRENT_USER
    • (Default) = "{hex values}"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings
    • WarnonBadCertRecving = "0"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings
    • EnableSPDY3_0 = "0"

Step 4

Reset Internet security settings

[ Learn More ]

Step 5

Scan your computer with your Trend Micro product to delete files detected as TSPY_ZBOT.YUYADD. 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

The following created files/folders/registry keys/registry entries cannot be identified by the user since there are no reference values in the created key. The only way it can be identified is by comparing the present system information with a backup. Note that the said components do not have to be deleted since it won't be harmful to the system.

  • HKEY_CURRENT_USER\Software\Microsoft
    • {random key 1}
  • HKEY_CURRENT_USER\Software\Microsoft\{random key 1}
    • {random 1} = "{hex values}"
  • HKEY_CURRENT_USER\Software\Microsoft\{random key 1}
    • {random 2} = "{hex values}"
  • %Application Data%\{random folder 1}
  • %Application Data%\{random folder 2}
  • %Application Data%\{random folder 2}\{random filename 2}.tmp
  • %Application Data%\{random folder 2}\{random filename 2}.{random extension}


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