PUA.Win32.OCCAMY.AA

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

File Size: 10,009,088 bytes

File Type: EXE

Memory Resident: Yes

Initial Samples Received Date: 14 Apr 2021

Arrival Details

This Potentially Unwanted Application 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 Potentially Unwanted Application drops the following files:

%User Temp%\~{Random Characters}.inf
{Malware Path}\~{Random Characters}.tmp
%Desktop%\常用网址导航.lnk -> redirects to http://www.{BLOCKED}.com/?zm
%User Temp%\{Random Characters}.bat -> checks for TCP connection, then deletes {Malware Path}\~{Random Characters}.tmp and itself
%User Temp%\{Random Characters}.exe -> deleted afterwards

It adds the following processes:

{Malware Path}\{Malware Filename}.exe /nstart
%User Temp%\{Random Characters}.exe /HomeRegAccess10
Rundll32.exe setupapi,InstallHinfSection DefaultInstall 132 %User Temp%\~{Random Characters}.inf
cmd /c %User Temp%\{Random Characters}.bat

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Local\Temp on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)

Other System Modifications

This Potentially Unwanted Application adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\360Safe\
safemon\userset
hp = http://www.{BLOCKED}.com/?{Random numbers}

HKEY_LOCAL_MACHINE\SOFTWARE\Baidu\
BaiduProtect\LockIEStartPage
Start Page = http://www.{BLOCKED}.com/?{Random numbers}

It modifies the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Policies\
System
ConsentPromptBehaviorAdmin = 0

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Policies\
System
PromptOnSecureDesktop = 0

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Policies\
System
EnableLUA = 0

HKEY_LOCAL_MACHINE\SOFTWARE\Policies\
Microsoft\Windows Defender
DisableAntiSpyware = 1

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Internet Explorer\MAIN
Start Page = http://www.{BLOCKED}.com/?{Random number}

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Internet Explorer\MAIN
Default_Page_URL = http://www.{BLOCKED}.com/?{Random number}

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Internet Explorer\MAIN
First Home Page = http://www.{BLOCKED}.com/?{Random number}

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Main
Start Page = http://www.{BLOCKED}.com/?{Random number}

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Main
Default_Page_URL = http://www.{BLOCKED}.com/?{Random number}

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Main
First Home Page = http://www.{BLOCKED}.com/?{Random number}

HKEY_CURRENT_USER\Software\Policies\
Microsoft\Internet Explorer\Main
Start Page = http://www.{BLOCKED}.com/?{Random number}

HKEY_LOCAL_MACHINE\SOFTWARE\Policies\
Microsoft\Internet Explorer\Main
Start Page = http://www.{BLOCKED}.com/?{Random number}

Other Details

Based on analysis of the codes, it has the following capabilities:

Connects to the following malicious URL:
- http://yun.u{BLOCKED}g.com/ns
- http://yun.u{BLOCKED}g.com/nys

It adds the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\Baidu

HKEY_LOCAL_MACHINE\SOFTWARE\Baidu\
BaiduProtect

HKEY_LOCAL_MACHINE\SOFTWARE\Baidu\
BaiduProtect\LockIEStartPage

HKEY_LOCAL_MACHINE\SOFTWARE\360Safe

HKEY_LOCAL_MACHINE\SOFTWARE\360Safe\
safemon

HKEY_LOCAL_MACHINE\SOFTWARE\360Safe\
safemon\userset

It does the following:

It requires to be executed with administrative rights to proceed to its malicious routine
It erases all the content of the %System%\drivers\etc\hosts file
It deletes all the files found in the %Favorites% directory
It adds the following possibly unwanted favorites on the IE Favorites bar:
- %Favorites%\百度一下.url
- %Favorites%\链接\百度一下.url
- %Favorites%\links\百度一下.url
- %Favorites%\网址导航.url
- %Favorites%\链接\网址导航.url
- %Favorites%\links\网址导航.url
- %Favorites%\淘宝网.url
- %Favorites%\链接\淘宝网.url
- %Favorites%\links\淘宝网.url
- %Favorites%\京东商城.url
- %Favorites%\链接\京东商城.url
- %Favorites%\links\京东商城.url
- %Favorites%\天猫精选.url
- %Favorites%\链接\天猫精选.url
- %Favorites%\links\天猫精选.url
- %Favorites%\拼多多.url
- %Favorites%\链接\拼多多.url
- %Favorites%\links\拼多多.url
- %Favorites%\购物导航.url
- %Favorites%\链接\购物导航.url
- %Favorites%\links\购物导航.url
- %Favorites%\携程网.url
- %Favorites%\链接\携程网.url
- %Favorites%\links\携程网.url
- %Favorites%\网页游戏.url
- %Favorites%\链接\网页游戏.url
- %Favorites%\links\网页游戏.url
- %Favorites%\游戏加速.url
- %Favorites%\链接\游戏加速.url
- %Favorites%\links\游戏加速.url

(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.. %Favorites% is the current user's Favorites folder, which is usually C:\Documents and Settings\{user name}\Favorites on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\Favorites on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)

Minimum Scan Engine: 9.800

SSAPI PATTERN File: 2.400.10

SSAPI PATTERN Date: 21 Apr 2021

Step 1

Trend Micro Predictive Machine Learning detects and blocks malware at the first sign of its existence, before it executes on your system. When enabled, your Trend Micro product detects this malware under the following machine learning name:

Troj.Win32.TRX.XXPE50FSX009

Step 2

Before doing any scans, Windows 7, Windows 8, Windows 8.1, and Windows 10 users must disable System Restore to allow full scanning of their computers.

Step 3

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 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.

%Desktop%\常用网址导航.lnk
%User Temp%\~{Random Characters}.inf

Step 5

Restore this modified 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\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System
- ConsentPromptBehaviorAdmin = 0
In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System
- PromptOnSecureDesktop = 0
In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System
- EnableLUA = 0
In HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows Defender
- DisableAntiSpyware = 1
In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\MAIN
- Start Page = http://www.136738.com/?{Random number}
In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\MAIN
- Default_Page_URL = http://www.136738.com/?{Random number}
In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\MAIN
- First Home Page = http://www.136738.com/?{Random Number}
In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
- Start Page = http://www.136738.com/?{Random Number}
In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
- Default_Page_URL = http://www.136738.com/?{Random Number}
In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
- First Home Page = http://www.136738.com/?{Random Number}
In HKEY_CURRENT_USER\Software\Policies\Microsoft\Internet Explorer\Main
- Start Page = http://www.136738.com/?{Random Number}
In HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Internet Explorer\Main
- Start Page = http://www.136738.com/?{Random Number}

To restore the registry value this malware/grayware modified:

Open Registry Editor.
» For Windows 7 and Server 2008 (R2) users, click the Start button, type regedit in the Search input field then press Enter.
» For Windows 8, 8.1, 10, and Server 2012 (R2) users, right-click on the lower left corner of the screen, click Run, type regedit in the text box provided, and then press Enter.
In the left panel, double-click the following:
HKEY_LOCAL_MACHINE>SOFTWARE>Microsoft>Windows>CurrentVersion>Policies>System
In the right panel, locate the registry value:
ConsentPromptBehaviorAdmin = 0
Again In the right panel, locate the registry value:
PromptOnSecureDesktop = 0
Again In the right panel, locate the registry value:
EnableLUA = 0
In the left panel, double-click the following:
HKEY_LOCAL_MACHINE>SOFTWARE>Policies>Microsoft>Windows Defender
In the right panel, locate the registry value:
DisableAntiSpyware = 1
In the left panel, double-click the following:
HKEY_LOCAL_MACHINE>SOFTWARE>Microsoft>Internet Explorer>MAIN
In the right panel, locate the registry value:
Start Page = http://www.136738.com/?{Random number}
Again In the right panel, locate the registry value:
Default_Page_URL = http://www.136738.com/?{Random number}
Again In the right panel, locate the registry value:
First Home Page = http://www.136738.com/?{Random Number}
In the left panel, double-click the following:
HKEY_CURRENT_USER>Software>Microsoft>Internet Explorer>Main
In the right panel, locate the registry value:
Start Page = http://www.136738.com/?{Random Number}
Again In the right panel, locate the registry value:
Default_Page_URL = http://www.136738.com/?{Random Number}
Again In the right panel, locate the registry value:
First Home Page = http://www.136738.com/?{Random Number}
In the left panel, double-click the following:
HKEY_CURRENT_USER>Software>Policies>Microsoft>Internet Explorer>Main
In the right panel, locate the registry value:
Start Page = http://www.136738.com/?{Random Number}
In the left panel, double-click the following:
HKEY_LOCAL_MACHINE>SOFTWARE>Policies>Microsoft>Internet Explorer>Main
In the right panel, locate the registry value:
Start Page = http://www.136738.com/?{Random Number}
Close Registry Editor.

Step 6

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\SOFTWARE\360Safe\safemon\userset
- hp = http://www.136738.com/?{Random numbers}
In HKEY_LOCAL_MACHINE\SOFTWARE\Baidu\BaiduProtect\LockIEStartPage
- Start Page = http://www.136738.com/?{Random numbers}

Step 7

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\SOFTWARE\Baidu
- HKEY_LOCAL_MACHINE\SOFTWARE\Baidu\BaiduProtect
In HKEY_LOCAL_MACHINE\SOFTWARE\Baidu\BaiduProtect\LockIEStartPage
- HKEY_LOCAL_MACHINE\SOFTWARE\360Safe
In HKEY_LOCAL_MACHINE\SOFTWARE\360Safe\safemon
- HKEY_LOCAL_MACHINE\SOFTWARE\360Safe\safemon\userset

Step 8

Scan your computer with your Trend Micro product to delete files detected as PUA.Win32.OCCAMY.AA. 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 the following Trend Micro Support pages for more information:

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