This email, which purports to be from cloud-based file transfer service WeTransfer claims that someone has sent you some files.
The email, which includes the WeTransfer logo, urges you to click a link to download your files.
As noted in more detail below, all unsolicited WeTransfer emails should be treated as suspicious.
While WeTransfer is a legitimate company, the way that it allows customers to use its service poses a significant security risk.
However, at least in the example that I discuss here, WeTransfer did not send the malicious email.
Instead, the email is a phishing scam designed to trick you into submitting your email account password to online criminals. The download links in the email are disguised so that they appear to point to the WeTransfer website. However, the links actually go to an unrelated website.
If you click on the download links in the email, a message warning that your session has expired will pop up in your browser window. The message asks you to enter the password for the email address that the scam email was sent to.
After you enter your email account password, you may be redirected to another page that prompts you to download malicious files. Or, you may be asked to supply further personal information.
Scammers can use the information you supplied to take control of your email account. They can then use it to distribute further spam, scam, and malware emails. The criminals may also be able to hijack services such as online storage or app stores that may be linked to the same account.
Here’s a screenshot of the scam email:
Here’s a screenshot of the fake session expired pop-up:
Be Wary of ALL WeTransfer Emails
While WeTransfer did not send the particular scam email discussed in this report, attackers can use the company’s system to send malicious messages.
Australian cyber emergency response team AusCert has been highly critical of WeTransfer because of the inadequate methods that the service users to validate email addresses. For example, attackers could enter the email address of a person or company that you know and trust as the sender of a file. You could then receive an email prompting you to download a malicious file that appears to come from this trusted friend or company.
However, WeTransfer perform minimal validation on email addresses provided by users, which is a major security hole. By default, users may enter any sender address.
This means that WeTransfer is allowing targeted phishing and malspam emails to be delivered, based on the strength of their own brand.
The company does offer a form of email verification, but, because the feature is opt-in rather than by default, it will not stop attackers exploiting the system.
Because of this security risk and the company’s failure to adequately address the issue, AusCert recommends that all emails sent from WeTransfer should be treated as suspicious.