How to avoid installation of Agent Tesla via Contract Agreement email?
Written by Tomas Meskauskas on (updated)
What is Contract Agreement email virus?
In most cases, cybercriminals behind malspam campaigns impersonate legitimate companies, organizations, or other entities. They send emails that have some malicious file attached to them or contain a website link designed to download a malicious file.
Usually, their emails are disguised as important, urgent letters containing an invoice, purchase order, or some other document. In one way or another, their goal is to trick recipients into downloading and opening a malicious file designed install malware on the operating system.
This malspam campaign is used to distribute Agent Tesla, a remote access trojan (RAT).
Cybercriminals behind this malspam campaign attempt to trick recipients into believing that they have received an email from SIA & AFRICA GENERAL TRADING L.L.C and the file attached to it (named "Signed Contract Agreement.zip") is a contract that should be signed and then sent back. Although, the file attached to this email is a ZIP archive file containing a malicious executable file (named "Signed Contract Agreement.exe").
It is important to mention that the filename of a malicious attachment may be different (e.g., "FlushAsyncInternald68.exe") in other email variants. In one way or another, the purpose of this malspam campaign is to trick recipients into executing a malicious file designed to install Agent Tesla.
Agent Tesla is the name of a remote access trojan that cybercriminals use to steal login credentials (usernames, email addresses, passwords), and other sensitive information by using its ability to record keyboard input and gather clipboard data. It means that Agent Tesla can be used to steal data that could be used to access email clients, messaging clients, certain FTP and VPN clients, download managers, etc.
In most cases, cybercriminals use hijacked accounts to steal identities, make unauthorized purchases, transactions, distribute malicious programs, trick other users into making money transactions, and for other purposes. Another important detail about Agent Tesla is that this RAT can be used to prevent victims from accessing the Task Manager, system registry, and executing commands via the Command Prompt.
It means that Agent Tesla can be used as a tool to infect computers with other malware, disable or even uninstall installed antivirus, anti-spyware or other software, and perform other tasks.
|Name||Contract Agreement spam|
|Threat Type||Trojan, password-stealing virus, banking malware, spyware.|
|Hoax||Email attachment is a contract that needs to be signed and sent back|
|Attachment(s)||Signed Contract Agreement.zip, FlushAsyncInternald68.zip, or a malicious file with another filename|
|Detection Names (FlushAsyncInternald68.exe)||Avast (Win32:MalwareX-gen [Trj]), BitDefender (Trojan.GenericKD.36982185), ESET-NOD32 (A Variant Of MSIL/Kryptik.ABDU), Kaspersky (HEUR:Trojan.MSIL.Taskun.gen), Microsoft (Trojan:MSIL/AgenteslaPacker!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.|
|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.
It is very common that cybercriminals use email as tool to trick users/recipients into infecting their computers with malware. More examples of malspam campaigns used to deliver malicious progrsms via links or files in emails are THUAN HIEP THANH Email Virus", "Pending Order Email Virus", and "Your Address Is Invalid Email Virus".
It is noteworthy that most cybercriminals use names and logos of legitimate companies, names of existing people, etc., to give their emails legitimacy. A couple examples of malicious programs that were or still are distributed via email are Snake Keylogger, FormBook, and LokiBot.
How did "Contract Agreement email virus" infect my computer?
This malspam campaign is used to trick recipients into executing a malicious executable extracted from the attached ZIP file. Research shows that the attached files can be named "Signed Contract Agreement.zip", "FlushAsyncInternald68.zip" or have another filename. Either way, cybercriminals behind this campaign succeed when recipients execute a malicious file designed to install Agent Tesla.
Although, malicious documents opened with newer versions do not install malicious software unless users enable macros commands (editing/content). In other words, newer MS Office versions have the "Protected View" mode that prevents malicious documents from automatically installing malware.
How to avoid installation of malware?
It is recommended not to download (or install) any programs or files using third-party software downloaders, installers, from untrustworthy websites, Peer-to-Peer networks (e.g., torrent clients, eMule), and so on. Files/programs downloaded from official websites and via direct download links.
Files (and website links) in irrelevant emails sent from unknown, suspicious addresses should not be opened - it is very common that such emails are used to trick recipients into installing malware (they contain malicious links or files). Installed programs have to be updated and activated properly - it has to be achieved using tools or functions that their official developers provide/have created.
It is strongly recommended not to use third-party tools for that - most of them are designed to install malware. Another detail about 'cracking' tools is that it is against the law to use them to activate licensed software.
Additionally, it is recommended to scan computers for viruses and other threats with a reputable security solution (anti-spyware or antivirus software). If you've already opened "Contract Agreement email virus" attachment, we recommend running a scan with Combo Cleaner Antivirus for Windows to automatically eliminate infiltrated malware.
Text presented in the "Contract Agreement email virus" email letter:
Subject: Signed Contract Agreement
Please find attached the contract agreement.
Kindly confirm, sign and send back to us.
We will appreciate your kind response.
ASIA & AFRICA GENERAL TRADING LLC
P O BOX 172363, AL RAS,
OPP. AL RAS METRO STATION,
DEIRA, DUBAI, UAE
TEL:- +971 4 2268241
FAX:- +971 4 2268251
Detection names of a malicious file designed to install Agent Tesla on VirusTotal:
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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:
- What is Contract Agreement 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:
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.
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.
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