Lampion Trojan Utilizes New Delivery through Cloud-Based Sharing

Found in Environments Protected By: Microsoft

By Andy Mann and Dylan Main, Cofense Phishing Defense Center

Analysts at the Cofense Phishing Defense Center (PDC) have recently analyzed an email asking users to download a “Proof of Payment” as well as other documents. While it is important to never click on the link(s) or download the attachment(s) of any suspicious email, if the recipient interacts with the link, it downloaded the malware Lampion.

The Lampion banking trojan has been around since 2019, but this is the first time it has been analyzed by the PDC. While it has not yet been determined who exactly is behind the malware, it is known for using a VBS loader. Fortunately, threat actors have been spotted by PDC analysts using a new form of delivery for that very VBS file. Using the trusted cloud platform used for payments, WeTransfer, threat actors are attempting to gain the trust of users while taking advantage of the service provided by the popular site. By leveraging a trusted payment site, it’s not surprising to see threat actors align their email messages for this process. A well-conditioned user quickly reported this email which mitigated the threat of malware infection.

Figure 1: Email Body

English translation: Good afternoon, I send proof of payment and documents on the link: hXXps://we[.]tl/t-pNvQIG8UJS I subscribe with high esteem and best regards

In Figure 1, the threat actor used a very simple email message to engage the recipient. The strongest tactic taken would be spoofing a legitimate company, which could potentially be a result of compromised credentials. The email sent to the recipient is sent a proof of payment and other documents, which are accessible at the URL hXXps://we[.]tl/t-pNvQIG8UJS. When the recipient interacts with the URL, they are directed to the page where they can download a ZIP file containing the documents referenced in the email.

Figure 2: Contents of the ZIP File

Figure 3: Strings from the First Wscript Process

Once the ZIP file is downloaded, its contents can be extracted to reveal a folder containing the two files seen in Figure 2. The VBS file, Comprovativo de pagamento de fatura_517-TEG_22-08-2022 20-09-24_28.vbs, is the file of concern as this launches the script, to lead the malicious process. Next, it will initiate a wscript process. Analyzing the strings in the memory of this process will result in finding references to two different VBS files, seen in Figure 3. This initial process created these files in the AppDataLocalTemp and AppDataRoaming directories. There are four VBS files created in total, each with random letters as a filename. The scripts in AppDataRoaming are less relevant. One file appears to be empty or was deleted during the process while the other is small with minimal functionality. The script, xjfgxhakusp.vbs, in AppDataLocalTemp is far more important.

Figure 4: URLs Leading to DLLs

While there are two VBS files in AppDataLocalTemp, the smaller script is only meant to initiate the other, larger script, xjfgxhakusp.vbs. It is a strange extra step taken by the threat actor. Upon running the larger script, another wscript process is initiated. This second wscript process reaches out to the two payload URLs in Figure 4. Both download the final DLL files. The bottom URL will download a password-protected ZIP that holds the DLL, but the password is hardcoded into the malicious process itself. The DLLs are then finally injected into the memory. As a banking Trojan, the Lampion mainly looks to steal the targets’ valuable information.

While email security continues to evolve to protect the organization, threat actors are constantly looking for opportunities to land in the inbox. This is why it is critical to provide your users with simulations aligned with the latest threats. Customers of the Cofense PDC can ease or confirm their suspicions by reporting suspicious emails to the PDC where an analyst will analyze the email for emerging threats. Contact us to learn more.

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