Attackers took a sophisticated dropper and disguised it as a fake DHL shipping invoice to distribute Ursnif malware.

Deep Instinct recently came across an attack email that attempted to trick people into opening a fake DHL invoice. This notice was actually an Excel spreadsheet that prompted users to enable a VBA macro contained therein.

Once activated, the macro displayed a fake progress bar to trick the user into thinking the malicious document was legitimate while it secretly ran malicious code in the background. The macro was also obfuscated and contained randomly generated comments to make the code appear benign and help it evade detection by security solutions.

After loading the fake progress bar, the VBA macro read a portion of the Excel file, called WMIC.exe, using a Shell() function and executed a PowerShell command. This PowerShell code also came with multiple layers of obfuscation, encoding and compression. Ultimately, the code executed the campaign’s Ursnif malware payload.

A History of DHL Malware Campaigns

This is not the first time threat actors have disguised their malware campaigns as DHL correspondence. Back in 2018, for instance, Yoroi Security discovered a malspam campaign that used the cover of a message from DHL to target Italian users with Gozi/Ursnif/IFSB/Dreambot variants.

That was just a few months before SI-Lab spotted a DHL-themed phishing campaign pushing Muncy malware. Not long thereafter, My Online Security saw an email that pretended to deliver a DHL shipment notification, but actually used a link in the email body and two Microsoft Word documents to spread various malware.

How to Defend Against Ursnif Attacks

Security professionals can help defend their organizations against DHL-themed Ursnif attacks by using ahead-of-threat detection to spot potentially malicious domains before they become active in phishing campaigns and other attacks. Organizations should also use test phishing engagements to educate their employees and test their awareness of social engineering attacks.

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