Recently, Morphisec Labs identified a significant increase in activity linked to Mispadu (also known as URSA), a banking trojan first flagged by ESET in 2019. Initially concentrated on LATAM countries and Spanish-speaking individuals, Mispadu has broadened its scope in the latest campaign.  

Introduction

Mispadu is a highly active banking trojan and Infostealer, now targeting diverse regions, including European countries, which previously were not targeted. Morphisec has prevented attacks from the same campaign across a variety of industries, including finance, services, motor vehicle manufacturing, law firms, and other commercial facilities.

Despite the geographic expansion, Mexico remains the primary target. The campaign has resulted in thousands of stolen credentials, with records dating back to April 2023. The threat actor leverages these credentials to orchestrate malicious phishing emails, posing a significant threat to recipients. 

Mispadu has been expanding outside of LATAM (Image generated by: Datawrapper.de)

Infection Chain 

The attack chain consists of multiple stages, which largely remain the same when compared to previous campaigns. However, most changes occur at the initial stages.

Delivery 

The image below demonstrates an example of a phishing email sent by the threat actor. Each email in this campaign included a PDF attachment, luring the victim to open their supposed invoice.

(Email body translated: “The XML and PDF of your invoice are available.”) 

Clicking the "View Full Invoice" (translated) button in the PDF will initiate the download of a ZIP file through a URL shortener service, insprl.com, which redirects to the payload stored on Yandex.Mail (a Russian free email service) as an attachment. 

https://webattach.mail.yandex[.]net/message_part_real/?sid=<sid>&name=<payload_name>  

First Stage VB Script 

The downloaded archive contains either an MSI installer or an HTA script, which ultimately leads to the deployment and execution of the first stage VB script. The MSI installer does that by invoking the export function of a DLL it contains under CustomActions. 

The export function decrypts a string, which contains the executed command responsible for dropping the first stage VB script. Additionally, it pops a message box to distract the victim from the malicious activity occurring in the background. The decryption algorithm used to decrypt the string is the same one used throughout the entire campaign. 

The executed command is obfuscated, its purpose is to drop a VB script into the public folder and invoke it. 

• The HTA operates similarly when executing the following command. Therefore, from this stage onward, the execution is similar to the HTA attack chain.
  

The downloaded script is the second stage VB script, evaluated and executed in memory. The C2 will not serve the payload unless the User-Agent field contains “(MSIE)”, which appended by default when executing the VB script that manner (Default value - Mozilla/4.0 (compatible; MSIE 7.0)…). 

Second Stage VB Script 

This script is heavily obfuscated and employs the same decryption algorithm as mentioned in the DLL. Before downloading and invoking the next stage, the script conducts several Anti-VM checks, including querying the computer’s model, manufacturer, and BIOS version, and comparing them to those associated with virtual machines. 

It will also compare the OS language code against hardcoded language codes that belong to the set of victim’s language codes. Additionally, it ensures that the computer name is not equal to JOHN-PC which is a common machine name used in sandboxes. 

If the aforementioned checks pass, the execution proceeds with downloading three files: 

1. A download of an archive file containing an obfuscated file from https://contdskl.bounceme[.]net/dhyhsh3am1.ahgrher2. This file will be later decrypted to be the final Mispadu payload.  
2. An obfuscated file is downloaded, decrypted to its archive form, and then unzipped. This file is a compiled AutoIT script utilized to load the final payload. Before invoking the request, it prompts for an index to download from <base_name>3<index>.<extension>, with the index incrementing by one for each request.
   
3. Another obfuscated file is downloaded, decrypted to its archive form, and unzipped. This file is a legitimate AutoIT executable used to launch the AutoIT script. 

Next, it will execute the legitimate AutoIT executable, passing the compiled script as a parameter. This script loads a DLL into memory and invokes its export function. The DLL is responsible for decrypting and injecting the encrypted Mispadu payload into memory. 

AutoIT Script 

The following is part of the decompiled AutoIT script, responsible loading the DLL into memory and invoking its export function. 

Injector DLL 

Once loaded to memory and invoked, the DLL decrypts the Mispadu payload downloaded in the second stage VB script and injects it to either attrib.exe or RegSvcs.exe. 

Mispadu Payload 

Similar to the preceding steps in the infection chain, the final Mispadu payload remains largely unchanged. It continues to utilize NirSoft’s legitimate WebBrowserPassView and Mail PassView to extract browser and email client credentials. It actively monitors foreground windows of websites and applications for specific strings, including bank names, cryptocurrency exchanges, finance-related applications, and email clients. Over 200 such services are monitored for potential credential exfiltration.  

Below is an example of credentials obtained from the C2 server, encoded using the algorithm employed across the infection chain. The threat actor divides the exfiltrated data into two parts. The first part comprises credentials extracted from email clients and browser passwords, while the second consists of email addresses obtained from the victim’s machine. Subsequently, the TA uses those email addresses to craft and distribute the malicious phishing emails. 

Conclusion 

The threat actor utilizes two command and control (C2) servers throughout the infection chain. The first C2 server is employed to fetch payloads utilized in the attack, such as the second stage VB script, Mispadu payload, and additional components. While the second C2 server is utilized for exfiltrating the extracted credentials. The first C2 server undergoes frequent alterations, whereas the second C2 server utilized for credential exfiltration remains relatively consistent across various campaigns. 

Based on the stolen credentials discovered on the C2 server, the earliest records date back to as early as April 2023 and continue to be ongoing up to the present day. Currently, there are more than 60K files in the C2 server. 

How Morphisec Can Help 

Mispadu is an extremely evasive threat that generally bypasses many of the leading solutions that organizations have in place today. Morphisec’s Automated Moving Target Defense (AMTD) stops attacks like Mispadu and other banking trojans across the attack chain, detecting malicious installers, scripts and the payload itself. Morphisec doesn’t rely on signature or behavioral patterns. Instead, it uses patented moving target defense technology to prevent the attack at its earliest stages, preemptively blocking attacks on memory and applications, effectively remediating the need for response. 

Schedule a demo today to see how Morphisec stops Mispadu and other new and emerging threats. 

Indicators of Compromise