Avoid clicking the link in the "Customer Complaint Report" malspam message

What is Customer Complaint email virus?

Cyber criminals often use emails as channels to trick users into downloading and installing malware onto their computers. Emails that are used to deliver malware are termed phishing messages or malspam. Usually, the emails contain an attachment or website link that opens a download page for a malicious file.

Note that cyber criminals behind malspam/phishing emails often claim to be legitimate companies. They also disguise their emails as important, official, and urgent.

This particular email is used to deliver Cobalt Strike.

This is a targeted and personalized malspam campaign and mentions the company name of the recipient. It is disguised as a message from the HR department and claims that someone has filed a customer complaint against its recipient. Furthermore, it claims that a recipient was fined two weeks' wages because of this issue.

The main purpose of this email is to trick recipients into reviewing the "complaint" and clicking a website link, which then opens a download page (e.g., Google Docs or another legitimate page or a deceptive site) for a malicious executable file. This file is designed to install Cobalt Strike, a tool that cyber criminals use for various purposes. For example, to upload and download files, log keystrokes (record keyboard input), execute commands via Command Prompt, etc.

In this way, the attackers use Cobalt strike to steal sensitive information (e.g., credit card details, login credentials, social security numbers, names, surnames) and to distribute (install) malware (e.g., Trojans, ransomware, cryptocurrency miners).

Therefore, by clicking the link in this email and opening a downloaded file, recipients could encounter problems such as data and monetary loss, identity theft, loss of access to various personal accounts, issues with online privacy, browsing safety, and more.

Threat Summary:

Name	Customer Complaint Report spam
Threat Type	Trojan, password-stealing virus, banking malware, spyware.
Hoax	A customer complaint is filed against the recipient
Detection Names	Avast (Win64:DangerousSig [Trj]), AVG (Win64:DangerousSig [Trj]), ESET-NOD32 (Win64/Rozena.BY), Kaspersky (Trojan.Win64.Shelma.iku), Microsoft (Backdoor:Win64/Bazarldr.MJK!MTB), Full List Of Detections (VirusTotal)
Symptoms	Trojans are designed to stealthily infiltrate the victim's computer and remain silent, and thus no particular symptoms are clearly visible on an infected machine.
Payload	Cobalt Strike
Distribution methods	Infected email attachments, malicious online advertisements, social engineering, software 'cracks'.
Damage	Stolen passwords and banking information, identity theft, the victim's computer added to a botnet.
Malware Removal (Windows)	To eliminate possible malware infections, scan your computer with legitimate antivirus software. Our security researchers recommend using Combo Cleaner. ▼ Download Combo Cleaner To use full-featured product, you have to purchase a license for Combo Cleaner. 7 days free trial available. Combo Cleaner is owned and operated by Rcs Lt, the parent company of PCRisk.com read more.

More examples of malspam campaigns/phishing emails are "Here's your PayPal invoice Email Virus", "International Air & Sea Freight Forwarder Email Virus", and "Ministero Dello Sviluppo Economico Email Virus". Phishing emails are generally employed to distribute malware or to extract sensitive information.

Falling for such scams can lead to serious problems. Therefore, check all suspicious emails before opening attachments or clicking links.

Examples of malware that cyber criminals distribute via email are Agent Tesla, Emotet, LokiBot, and Ursnif.

How did Cobalt Strike infect my computer?

Recipients often install malware onto their computers when they download and open a malicious attachment, or click a link and then open a downloaded file. In this particular case, Cobalt Strike is installed after executing a malicious executable file downloaded via the provided website link.

Note that a link in this phishing email may open a legitimate website. For example, Google Docs page (docs.google[.]com). When cyber criminals use email attachments to distribute malware, they usually attach a malicious PDF or Microsoft Office document, JavaScript file, ZIP, RAR or another archive file, or an executable file (.exe).

Note that malicious MS Office documents can install malware only when users enable editing/content (macros commands). If the documents are opened with MS Office versions prior to 2010, however, the documents install malicious software automatically, since these older versions do not include "Protected View" mode.

How to avoid installation of malware

To avoid infecting the system with malware spread through spam mail, you are strongly advised not to open suspicious or irrelevant emails, especially those with any attachments or links present in them. Use official and verified download channels.

Additionally, all programs must be activated and updated with tools/functions provided by legitimate developers, since illegal activation tools ("cracks") and third party updaters commonly proliferate malicious software.

To ensure device integrity and user safety, it is paramount to have reputable anti-virus/anti-spyware software installed and kept updated. Furthermore, use these programs to run regular system scans and to remove detected/potential threats.

Do not trust irrelevant emails that contain attachments or website links, especially if received from unknown, suspicious addresses.

Fake update tools infect systems by installing malicious programs rather than updates/fixes for installed software, or by exploiting bugs/flaws of outdated software that is installed on the computer.

Further encryption of any unaffected files can be prevented by uninstalling the ransomware, however, already compromised files remain encrypted even after removal of the rogue software and can only be recovered from a backup.

If you have already opened a "Customer Complaint email virus" attachment, we recommend running a scan with Combo Cleaner Antivirus for Windows to automatically eliminate infiltrated malware.

Text presented in the email:

Subject: [recipient's company name] complaint

By [recipient's company name] head office HR request, here is a copy of your Customer Complaint Report #852-2-25

You will get two weeks payout. I am very sorry for that.

Customer Complaint Report on you in PDF online: hxxps://customer-complaint-25febr.getresponsepages.com/

[recipient's company name] outsource HR assistant

Screenshot of the download page for the executable file that installs Cobalt Strike:

Screenshot of the malicious file "Customer Statement.exe" (its name may vary) detected as a threat by multiple detection engines:

Instant automatic malware removal: Manual threat removal might be a lengthy and complicated process that requires advanced IT 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:
▼ DOWNLOAD Combo Cleaner By downloading any software listed on this website you agree to our Privacy Policy and Terms of Use. To use full-featured product, you have to purchase a license for Combo Cleaner. 7 days free trial available. Combo Cleaner is owned and operated by Rcs Lt, the parent company of PCRisk.com read more.

Quick menu:

• What is Customer Complaint Report spam?
• Types of malicious emails.
• How to spot a malicious email?
• What to do if you fell for an email scam?

Types of malicious emails:

Phishing Emails

Most commonly, cybercriminals use deceptive emails to trick Internet users into giving away their sensitive private information, for example, login information for various online services, email accounts, or online banking information.

Such attacks are called phishing. In a phishing attack, cybercriminals usually send an email message with some popular service logo (for example, Microsoft, DHL, Amazon, Netflix), create urgency (wrong shipping address, expired password, etc.), and place a link which they hope their potential victims will click on.

After clicking the link presented in such email message, victims are redirected to a fake website that looks identical or extremely similar to the original one. Victims are then asked to enter their password, credit card details, or some other information that gets stolen by cybercriminals.

Emails with Malicious Attachments

Another popular attack vector is email spam with malicious attachments that infect users' computers with malware. Malicious attachments usually carry trojans that are capable of stealing passwords, banking information, and other sensitive information.

In such attacks, cybercriminals' main goal is to trick their potential victims into opening an infected email attachment. To achieve this goal, email messages usually talk about recently received invoices, faxes, or voice messages.

If a potential victim falls for the lure and opens the attachment, their computers get infected, and cybercriminals can collect a lot of sensitive information.

While it's a more complicated method to steal personal information (spam filters and antivirus programs usually detect such attempts), if successful, cybercriminals can get a much wider array of data and can collect information for a long period of time.

Sextortion Emails

This is a type of phishing. In this case, users receive an email claiming that a cybercriminal could access the webcam of the potential victim and has a video recording of one's masturbation.

To get rid of the video, victims are asked to pay a ransom (usually using Bitcoin or another cryptocurrency). Nevertheless, all of these claims are false - users who receive such emails should ignore and delete them.

How to spot a malicious email?

While cyber criminals try to make their lure emails look trustworthy, here are some things that you should look for when trying to spot a phishing email:

• Check the sender's ("from") email address: Hover your mouse over the "from" address and check if it's legitimate. For example, if you received an email from Microsoft, be sure to check if the email address is @microsoft.com and not something suspicious like @m1crosoft.com, @microsfot.com, @account-security-noreply.com, etc.
• Check for generic greetings: If the greeting in the email is "Dear user", "Dear @youremail.com", "Dear valued customer", this should raise suspiciousness. Most commonly, companies call you by your name. Lack of this information could signal a phishing attempt.
• Check the links in the email: Hover your mouse over the link presented in the email, if the link that appears seems suspicious, don't click it. For example, if you received an email from Microsoft and the link in the email shows that it will go to firebasestorage.googleapis.com/v0... you shouldn't trust it. It's best not to click any links in the emails but to visit the company website that sent you the email in the first place.
• Don't blindly trust email attachments: Most commonly, legitimate companies will ask you to log in to their website and to view any documents there; if you received an email with an attachment, it's a good idea to scan it with an antivirus application. Infected email attachments are a common attack vector used by cybercriminals.

To minimise the risk of opening phishing and malicious emails we recommend using Combo Cleaner Antivirus for Windows. 

Example of a spam email:

What to do if you fell for an email scam?

• If you clicked on a link in a phishing email and entered your password - be sure to change your password as soon as possible. Usually, cybercriminals collect stolen credentials and then sell them to other groups that use them for malicious purposes. If you change your password in a timely manner, there's a chance that criminals won't have enough time to do any damage.
• If you entered your credit card information - contact your bank as soon as possible and explain the situation. There's a good chance that you will need to cancel your compromised credit card and get a new one.
• If you see any signs of identity theft - you should immediately contact the Federal Trade Commission. This institution will collect information about your situation and create a personal recovery plan.
• If you opened a malicious attachment - your computer is probably infected, you should scan it with a reputable antivirus application. For this purpose, we recommend using Combo Cleaner Antivirus for Windows.
• Help other Internet users - report phishing emails to Anti-Phishing Working Group, FBI’s Internet Crime Complaint Center, National Fraud Information Center and U.S. Department of Justice.

▼ Show Discussion