When it comes to email, there are a number of ways through which a cyberattacker can target a victim. Malicious links, persuasive language, and dangerous attachments are all used to swindle unknowing individuals out of their sensitive data and money.
So how can you avoid falling victim to this? What actually is a malicious attachment? And how can you spot a suspicious attachment in an email?
What Is a Malicious Attachment?
It’s pretty common to receive attachments in everyday emails. Documents, audio files, and images are all often attached to emails. But not every attachment you receive is necessarily benign.
Malicious attachments are those which are used to spread malware to someone’s device. Cyberattackers need vectors through which they can spread these dangerous programs; this can be done in a number of ways, with malicious attachments being a popular choice.
When a victim downloads a malicious attachment, they are actually downloading malware onto their device. Depending on what kind of malware this is, their device might be affected in different ways. But the consequences of downloading a malicious attachment could be severe.
5 Signs of a Malicious Attachment
This is why it’s important that you know how to spot a malicious attachment so the chances of unknowingly downloading malware onto your device are lowered. So how can you recognize an attachment that’s potentially harmful?
1. Analyze the File Type
When you receive any kind of attachment via email, you’ll be able to see the extension, or suffix, of the file. There are many different file types out there, many of which you’ve likely seen before, such as .jpg, .zip, or .pdf. And while there are no definitively malicious file types, there are some that are commonly used to spread malware.
The main types of suspicious file attachments you should be aware of are: exe, .vbs, .scr, .cmd, and .js. It’s these file types that can be leveraged to spread malware. For example, .exe files, or executable files, can sometimes be viruses. Executable files contain sets of instructions that are used to perform certain functions on a device. Because of this, executable files can be ideal vectors for malware.
This is why you always need to check the file type of an attachment before opening it. This is especially true if the attachment has been sent from a new or unknown address.
2. Check the Context
The context of an email can also be indicative of whether a given attachment is malicious. For example, if you’ve received an email wherein the sender claims to have attached a document, but the attachment is in an MP3 format, then chances are you’re dealing with a misleading attachment at the very least.
So, it’s worth knowing what different file types mean so that you can more effectively avoid malicious attachments within emails.
3. Check the Sender’s Address
A key step in weeding out malicious emails, and therefore malicious attachments, is checking the email address of the sender. An attacker cannot directly replicate and use the address of a trusted source but will try to create addresses that are very similar. This makes it harder for a target to notice they’re communicating with a threat actor.
For example, an attacker may slightly alter the company name within the address (e.g. “w4lmart” instead of “walmart”). When you receive any kind of email from a new sender, make sure you have a quick look at the address to determine whether it’s suspicious.
4. Use an Attachment Scanner
Yes, there are actually programs out there that can scan attachments for you! This can make it super quick and easy to verify whether an email is safe or not. Some antivirus programs come with attachment scanning features, but you can also download separate attachment scanners if your chosen antivirus program does not offer this option, such as the VirusTotal Online Scanner.
5. Utilize Anti-Spam Features
Today, most email providers offer some kind of anti-spam feature, which filters out potentially harmful emails from your main inbox and places them in a spam folder. While anti-spam protocols aren’t perfect, they can help you to avoid dangerous emails, and therefore dangerous attachments. But you may want to check your spam folder regularly when using an anti-spam feature, as legitimate emails may sometimes be misidentified and hidden from your main inbox.
Malicious Attachments: Dangerous but Avoidable
A huge number of individuals have already been hit by malicious attachments, with cybercriminals using email as a key vector for spreading them. But there are things you can do to weed out malicious attachments so that you can keep your devices safe from malware. Just remain skeptical and vigilant.