On May 29, 2024, the US Department of Justice (DOJ) announced it had dismantled what was likely the world’s largest botnet ever. This botnet, called “911 S5,” infected systems at over 19 million IP addresses across more than 190 countries. The main sources of income for the operators, who stole a billions of dollars across a decade, came from committing pandemic and unemployment fraud, and by selling access to child exploitation materials.

The botnet operator generated millions of dollars by offering cybercriminals access to these infected IP addresses. As part of this operation, a Chinese national, YunHe Wang, was arrested. Wang is reportedly the proprietor of the popular service.

Of the infected Windows devices, 613,841 IP addresses were located in the United States. The DOJ also called the botnet a residential proxy service. Residential proxy networks allow someone in control to rent out a residential IP address which then can be used as a relay for their internet communications. This allows them to hide their true location behind the residential proxy. Cybercriminals used this service to engage in cyberattacks, large-scale fraud, child exploitation, harassment, bomb threats, and export violations.

To set up this botnet, Wang and his associates provided users with free, illegitimate VPN applications that were created to connect to the 911 S5 service. Unaware of the proxy backdoor, once users downloaded and installed these VPN applications, they unknowingly became part of the 911 S5 botnet.

Sometimes the VPN applications were bundled with games and other software and installed without user consent.

For this reason, the FBI has published a public service announcement (PSA) to help users find out if they have been affected by this botnet.

Users can start by going over this list of malicious VPN applications associated with the 911 S5 botnet:

• MaskVPN
• DewVPN
• PaladinVPN
• ProxyGate
• ShieldVPN
• ShineVPN

If you have one of these VPN applications installed, sometimes you can find an uninstaller located under the Start menu option of the VPN application. If present, you can use that uninstall option.

If the application doesn’t present you with an uninstall option, then follow the steps below to attempt to uninstall the application:

• Click on the Start menu (Windows button) and type “Add or remove programs” to bring up the “Add and Remove Programs” menu.
• Search for the name of the malicious VPN application.
• Once you find the application in the list, click on the application name, and select the “Uninstall” option.

Once you have uninstalled the application, you will want to make sure it’s no longer active. To do that, open the Windows Task manager. Press Control+Alt+Delete on the keyboard and select the “Task Manager” option or right-click on the Start menu (Windows button) and select the “Task Manager” option.

In Task Manager look under the “Process” tab for the following processes:

• MaskVPN (mask_svc.exe)
• DewVPN (dew_svc.exe)
• PaladinVPN (pldsvc.exe)
• ProxyGate (proxygate.exe, cloud.exe)
• ShieldVPN (shieldsvc.exe)
• ShineVPN (shsvc.exe)

If found, select the service related to one of the identified malicious software applications running in the process tab and select the option “End task” to attempt to stop the process from running.

Or, download Malwarebytes Premium (there is a free trial) and run a scan.

Whether you’re using the free or paid version of the app, you can manually run a scan to check for threats on your device. 

1. Open the app.
2. On the main dashboard, click the Scan button.
3. A progress page appears while the scan runs.
4. After the scan finishes, it displays the Threat scan summary.
   • If the scan detected no threats: Click Done.
   • If the scan detected threats on your device: Review the threats found on your computer. From here, you can manually quarantine threats by selecting a detection and clicking Quarantine.
5. Click View Report or View Scan Report to see a history of prior scans. After viewing the threat report, close the scanner window.

If neither of these options, including the Malwarebytes scan, resolve the problem, the FBI has more elaborate instructions. You can also contact the Malwarebytes Support team to assist you.

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A list of topics we covered in the week of April 1 to April 7 of 2024

Last week on Malwarebytes Labs:

• 60% of small businesses are concerned about cybersecurity threats
• Cookie consent choices are just being ignored by some websites
• Bing ad for NordVPN leads to SecTopRAT
• Jackson County hit by ransomware, declares state of emergency
• Google patches critical vulnerability for Androids with Qualcomm chips
• Google Chrome gets ‘Device Bound Session Credentials’ to stop cookie theft
• AT&T confirms 73 million people affected by data breach
• Trusted Advisor now available for Mac, iOS, and Android
• 2024 State of Malware in Education report: Top 6 cyberthreats facing K-12 and Higher Ed
• Free VPN apps turn Android phones into criminal proxies

Stay safe!

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Researchers at HUMAN’s Satori Threat Intelligence have discovered a disturbing number of VPN apps that turn users’ devices into proxies for cybercriminals without their knowledge, as part of a camapign called PROXYLIB.

Cybercriminals and state actors like to send their traffic through other people’s devices, known as proxies. This allows them to use somebody else’s resources to get their work done, it masks the origin of their attacks so they are less likely to get blocked, and it makes it easy for them to keep operating if one of their proxies is blocked.

An entire underground market of proxy networks exists to service this desire, offering cybercriminals flexible, scalable platfroms from which to launch activities like advertising fraud, password spraying, and credential stuffing attacks.

The researchers at HUMAN found 28 apps on Google Play that turned unsuspecting Android devices into proxies for criminals. 17 of the apps were free VPNs. All of them have now been removed from Google Play.

The operation was dubbed PROXYLIB after a code library shared by all the apps that was responsible for enrolling devices into the ciminal network.

HUMAN also found hundreds of apps in third-party repositories that appeared to use the LumiApps toolkit, a Software Development Kit (SDK) which can be used to load PROXYLIB. They also tied PROXYLIB to another platform that specializes in selling access to proxy nodes, called Asocks.

Protection and removal

Android users are now automatically protected from the PROXYLIB attack by Google Play Protect, which is on by default on Android devices with Google Play Services.

The affected apps can be uninstalled using a mobile device’s uninstall functionality. However, apps like these may be made available under different names in future, which is where apps like Malwarebytes for Android can help.

Recommendations to stay clear of PROXYLIB are:

• Do not install apps from third-party websites.
• Do not install free VPNs.
• Use Malwarebytes for Android.

Victims of novel attacks like PROXYLIB might notice slow traffic, because their bandwidth is in use for other purposes. And at some point their IP address may be blocked by websites and other services.

The researchers included a list of applications they uncovered as part of PROXYLIB. If you installed any of the apps on the list before they were removed from Google Play you will need to uninstall them.

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We don’t just report on privacy—we offer you the option to use it.

Privacy risks should never spread beyond a headline. Keep your online privacy yours by using Malwarebytes Privacy VPN.