Incidents

Brazilian banking Trojans meet PowerShell

Crooks are always creating new ways to improve the malware they use to target bank accounts, and now Brazilian bad guys have made an important addition to their arsenal: the use of PowerShell. Brazil is the most infected country worldwide when it comes to banking Trojans, according to our Q1 2016 report, and the quality of the malware is evolving dramatically. We found Trojan-Proxy.PowerShell.Agent.a in the wild a few days ago, marking a new achievement by Brazil’s cybercriminals.

The malware is distributed using a malicious email campaign disguised as a receipt from a mobile operator with a malicious .PIF file. After the file is executed it changes the proxy configuration in Internet Explorer to a malicious proxy server that redirects connections to phishing pages for Brazilian banks. It’s the same technique used by malicious PACs that we described in 2013, but this time no PACs are used; the changes in the system are made using a PowerShell script. As Windows 7 and newer OS versions are now the most popular in Brazil, the malware will not face a problem running on victims’ computers.

The malware has no C&C communication. After execution it spawned the process “powershell.exe” with the command line “-ExecutionPolicy Bypass -File %TEMP%\599D.tmp\599E.ps1” aiming to bypass PowerShell execution policies. The .ps1 file in the temp folder uses random names. It’s a base64 encoded script capable of making changes in the system.

Brazilian banking Trojans meet PowerShell

After some deobfuscation we can see the goal of the script: to change the Internet Settings key and enable a proxy server on it:

Brazilian banking Trojans meet PowerShell

And this is the result in the browser of the victim – a small change in the proxy settings:

Brazilian banking Trojans meet PowerShell

This change will not only affect IE but all other browsers installed in the system as well, as they tend to use the same proxy configuration set on IE. The proxy domains used in the attack are listed below. All of them use dynamic DNS services and their goal is to redirect all traffic to a server located in the Netherlands (89.34.99.45), where there are several phishing pages for Brazilian banks:

gbplugin.[REMOVED].com.br
moduloseguro.[REMOVED].com.br
x0x0.[REMOVED].com.br
X1x1.[REMOVED].com.br

The malware also has other features of interest: it checks for the language of the OS and aborts if it’s not PTBR, a clever trick to avoid infecting Windows versions in languages other than Brazilian Portuguese.

To protect a network against malware that uses PowerShell, it is important to modify its execution, using administrative templates that only allow signed scripts. We are sure this is the first of many that Brazil’s bad guys will code.

Hash of the malware: cancelamento.pif -> MD5: 9419e7cd60487532313a43559b195cb0

Brazilian banking Trojans meet PowerShell

Your email address will not be published. Required fields are marked *

 

Reports

Lazarus targets defense industry with ThreatNeedle

In mid-2020, we realized that Lazarus was launching attacks on the defense industry using the ThreatNeedle cluster, an advanced malware cluster of Manuscrypt (a.k.a. NukeSped). While investigating this activity, we were able to observe the complete life cycle of an attack, uncovering more technical details and links to the group’s other campaigns.

Sunburst backdoor – code overlaps with Kazuar

While looking at the Sunburst backdoor, we discovered several features that overlap with a previously identified backdoor known as Kazuar. Our observations shows that Kazuar was used together with Turla tools during multiple breaches in past years.

Lazarus covets COVID-19-related intelligence

As the COVID-19 crisis grinds on, some threat actors are trying to speed up vaccine development by any means available. We have found evidence that the Lazarus group is going after intelligence that could help these efforts by attacking entities related to COVID-19 research.

Sunburst: connecting the dots in the DNS requests

We matched private and public DNS data for the SUNBURST-malware root C2 domain with the CNAME records, to identify who was targeted for further exploitation. In total, we analyzed 1722 DNS records, leading to 1026 unique target name parts and 964 unique UIDs.

Subscribe to our weekly e-mails

The hottest research right in your inbox