In a recent campaign uncovered by CyberArmor analysts, cybercriminals exploited the theme of official Social Security statements to deceive over 2,000 individuals into downloading malware. The attack involved a highly convincing phishing lure designed to appear as a legitimate communication from the Social Security Administration (SSA).  Figure 1 shows the overview of the campaign.

Figure 1: Malware Overview

Phishing Technique

The cybercriminals sent emails to targets containing a URL that directed them to a phishing page hosted on Amazon Web Services (AmazonAWS). This hosting choice was likely intended to lend legitimacy, as many users inherently trust the Amazon brand.  Figure 2 shows the phish webpage.

  • hxxps://odertaoa[.]s3.us-east-1.amazonaws.com/ssa/US/index.html
Figure 2: Phish Page

Once the user clicked on ‘Access The Statement,’ the phishing page redirected to a second page with instructions for downloading the file. After the download, the page displayed further instructions on how to execute the file, as shown in Figure 3.

Figure 3: Phish Instructions

Malware File Overview

The malware has the following properties.

Malware Behavior

The malware is a .NET application loader. Upon execution, it loads and runs a .NET application embedded in its resources. The loader executes two main components: the first is a .NET resolver responsible for loading additional files stored in the ‘FILES’ folder—these are necessary to run the ScreenConnect software. Once the dependencies are loaded, the loader executes the ‘ENTRYPOINT’ file, which functions as the primary backdoor. This component retrieves the command-and-control (C2) address embedded within the loader and launches ScreenConnect to establish a silent connection to the cybercriminal’s server. Figure 4 shows the resource files embedded within the loader.

Figure 4: Loader Resources

The configuration below represents the C2 settings embedded within the loader file.

<?xml version=”1.0″ encoding=”utf-8″?>
<configuration>
<configSections>
<section name=”ScreenConnect.ApplicationSettings” type=”System.Configuration.ClientSettingsSection, System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089″ />
</configSections>
<ScreenConnect.ApplicationSettings>
<setting name=”ClientLaunchParametersConstraint” serializeAs=”String”>
<value>?h=secure.ratoscbom.com&amp;p=8041&amp;k=BgIAAACkAABSU0ExAA…</value>
</setting>
</ScreenConnect.ApplicationSettings>
</configuration>

Scope of Impact

CyberArmor’s telemetry confirms that over 2,000 users interacted with the phishing lure, and a significant percentage installed the malware unknowingly.

Recommendations

Indicators

CyberArmor continues to monitor this campaign and related infrastructure. Organizations are advised to alert their users, especially those in finance and healthcare sectors, to remain vigilant.