Do not trust the system has detected irregular activity email scam

Also Known As: possible malware infections
Damage level: Medium

What is system has detected irregular activity email scam?

It is common for an email to be used by scammers as a tool to trick recipients into providing personal information, for example, login credentials, credit card details, social security numbers. Recipients are encouraged to send sensitive information via email or enter it on the provided website. Typically, phishing emails look like letters from legitimate companies.

System has detected irregular activity email scam

System has detected irregular activity email scam in detail

This phishing email is disguised as a letter from email service provider. Scammers behind it attempt to trick recipients into believing that a system has detected some irregular activity and stopped them from receiving emails. Their main goal is to trick recipients into clicking the "Resolve issues now" button designed to open deceptive websites.

The aforementioned button opens fake Yahoo Mail, Gmail, or other login pages - it depends on the recipient's email address. For example, if a recipient uses Gmail as an email service provider, then the "Resolve issues now" button opens a fake Gmail login page. If a recipient uses Yahoo Mail, then that button opens a fake Yahoo Mail login page, etc.

Scammers behind this phishing email attempt to trick recipients into providing their email login credentials (email addresses and passwords). Typically, stolen email login credentials are used to access personal emails, send emails scams, deliver malware, and for other malicious purposes.

It is also common that scammers try to use stolen login credentials to access other accounts (for example, social media, banking accounts). They succeed when users use the same login credentials for more than one account. For this reasons, it is strongly recommended to use different passwords.

Threat Summary:
Name System Has Detected Irregular Activity Email Scam
Threat Type Phishing, Scam, Social Engineering, Fraud
Fake Claim Recipients have stopped from receiving emails due to suspicious activity
Related Domain test.ostetricamente[.]com
Detection Names (test.ostetricamente[.]com) Certego (Phishing), CRDF (Malicious), CyRadar (Malicious), Fortinet (Phishing), Full List Of Detections (VirusTotal)
Disguise Letter from email service provider
Symptoms Unauthorized online purchases, changed online account passwords, identity theft, illegal access of the computer.
Distribution methods Deceptive emails, rogue online pop-up ads, search engine poisoning techniques, misspelled domains.
Damage Loss of sensitive private information, monetary loss, identity theft.
Malware Removal (Windows)

To eliminate possible malware infections, scan your computer with legitimate antivirus software. Our security researchers recommend using Combo Cleaner.
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Phishing emails in general

In conclusion, this phishing email is used to extract login credentials for email accounts via fake Yahoo Mail, Gmail and other login pages. More examples of emails of this type are "Email Cloud Scam", "Voicemail Email Scam", and "Wage Increase Email Scam". It is important to know that email can be used as a channel for malware distribution.

How do spam campaigns infect computers?

When cybercriminals use email to deliver malware, they send emails with malicious files attached to them or contain malicious links. In one way or another, their main goal is to trick recipients into downloading and opening a malicious file, for example, archive file (like ZIP, RAR), executable file (like EXE), PDF document, Microsoft Office document, JavaScript file.

It is important to mention that malicious documents opened with MS Office 2010 and newer releases do not install malware unless users enable macros commands (editing/content). MS Office 2010 and later releases have the "Protected Mode" feature that opens documents in read-only mode and disables editing functions.

Older MS Office versions (released before 2010) do not have the "Protected View" mode. Therefore, malicious documents opened with those versions infect computers as soon as they are opened.

How to avoid installation of malware?

Files and links in emails received from unknown, suspicious addresses should not be opened (especially if those emails are irrelevant). It is common that files or links in emails of this kind are used to deliver malware. Typically, those files are presented as important documents (for example, bank statements, purchase orders).

Unofficial websites, third-party downloaders, Peer-to-Peer networks (such as torrent clients, eMule, and so on), free file hosting pages, etc., should not be used as sources to download files, programs - they can be used to distribute malware. Files and programs should be downloaded from legitimate websites and via direct links.

Installed software has to be updated and activated with implemented functions (or tools) provided by its official developers. Third-party (unofficial) tools can be designed to infect computers. Moreover, it is against the law to use cracking tools to activate software (use pirated software).

Also, it is recommended to have a reputable antivirus or anti-spyware software installed and the operating system and run scans with it on a regular basis. If you've already opened malicious attachments, we recommend running a scan with Combo Cleaner Antivirus for Windows to automatically eliminate infiltrated malware.

Text presented in the System has detected irregular activity email letter:

Subject: System deliveries error


Our system has detected irregular activity related to
As a precautionary measure, deliveries are put to stop.

egain access proceed to resolve.
This link only works for the direct recipients of this message.
Resolve issues now

Screenshot of the fake Yahoo Mail login page used to steal login credentials:

system has detected irregular activity email scam deceptive website for yahoo users

Screenshot of the fake Gmail login page used to steal login credentials:

system has detected irregular activity email scam deceptive website for gmail users

Instant automatic malware removal: Manual threat removal might be a lengthy and complicated process that requires advanced computer skills. Combo Cleaner is a professional automatic malware removal tool that is recommended to get rid of malware. Download it by clicking the button below:
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How to remove malware manually?

Manual malware removal is a complicated task - usually it is best to allow antivirus or anti-malware programs to do this automatically. To remove this malware we recommend using Combo Cleaner Antivirus for Windows.

If you wish to remove malware manually, the first step is to identify the name of the malware that you are trying to remove. Here is an example of a suspicious program running on a user's computer:

malicious process running on user's computer sample

If you checked the list of programs running on your computer, for example, using task manager, and identified a program that looks suspicious, you should continue with these steps:

manual malware removal step 1Download a program called Autoruns. This program shows auto-start applications, Registry, and file system locations:

screenshot of autoruns application

manual malware removal step 2Restart your computer into Safe Mode:

Windows XP and Windows 7 users: Start your computer in Safe Mode. Click Start, click Shut Down, click Restart, click OK. During your computer start process, press the F8 key on your keyboard multiple times until you see the Windows Advanced Option menu, and then select Safe Mode with Networking from the list.

Safe Mode with Networking

Video showing how to start Windows 7 in "Safe Mode with Networking":

Windows 8 users: Start Windows 8 is Safe Mode with Networking - Go to Windows 8 Start Screen, type Advanced, in the search results select Settings. Click Advanced startup options, in the opened "General PC Settings" window, select Advanced startup.

Click the "Restart now" button. Your computer will now restart into the "Advanced Startup options menu". Click the "Troubleshoot" button, and then click the "Advanced options" button. In the advanced option screen, click "Startup settings". Click the "Restart" button. Your PC will restart into the Startup Settings screen. Press F5 to boot in Safe Mode with Networking.

Windows 8 Safe Mode with networking

Video showing how to start Windows 8 in "Safe Mode with Networking":

Windows 10 users: Click the Windows logo and select the Power icon. In the opened menu click "Restart" while holding "Shift" button on your keyboard. In the "choose an option" window click on the "Troubleshoot", next select "Advanced options". In the advanced options menu select "Startup Settings" and click on the "Restart" button.

In the following window you should click the "F5" button on your keyboard. This will restart your operating system in safe mode with networking.

windows 10 safe mode with networking

Video showing how to start Windows 10 in "Safe Mode with Networking":


manual malware removal step 3Extract the downloaded archive and run the Autoruns.exe file.

extract autoruns.zip and run autoruns.exe

manual malware removal step 4In the Autoruns application, click "Options" at the top and uncheck "Hide Empty Locations" and "Hide Windows Entries" options. After this procedure, click the "Refresh" icon.

Click 'Options' at the top and uncheck 'Hide Empty Locations' and 'Hide Windows Entries' options

manual malware removal step 5Check the list provided by the Autoruns application and locate the malware file that you want to eliminate.

You should write down its full path and name. Note that some malware hides process names under legitimate Windows process names. At this stage, it is very important to avoid removing system files. After you locate the suspicious program you wish to remove, right click your mouse over its name and choose "Delete".

locate the malware file you want to remove

After removing the malware through the Autoruns application (this ensures that the malware will not run automatically on the next system startup), you should search for the malware name on your computer. Be sure to enable hidden files and folders before proceeding. If you find the filename of the malware, be sure to remove it.

searching for malware file on your computer

Reboot your computer in normal mode. Following these steps should remove any malware from your computer. Note that manual threat removal requires advanced computer skills. If you do not have these skills, leave malware removal to antivirus and anti-malware programs.

These steps might not work with advanced malware infections. As always it is best to prevent infection than try to remove malware later. To keep your computer safe, install the latest operating system updates and use antivirus software. To be sure your computer is free of malware infections, we recommend scanning it with Combo Cleaner Antivirus for Windows.

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About the author:

Tomas Meskauskas

Tomas Meskauskas - expert security researcher, professional malware analyst.

I am passionate about computer security and technology. I have an experience of over 10 years working in various companies related to computer technical issue solving and Internet security. I have been working as an author and editor for pcrisk.com since 2010. Follow me on Twitter and LinkedIn to stay informed about the latest online security threats. Contact Tomas Meskauskas.

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Malware activity

Global malware activity level today:

Medium threat activity

Increased attack rate of infections detected within the last 24 hours.

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