Redline Stealer: What is it, and how does it work?

Redline Stealer is a dangerous remote access trojan (RAT) that infiltrates corporate systems to steal sensitive information. Employee passwords, confidential corporate data, and even your company’s finances can become the loot of a cybercriminal behind Redline. Read the article to learn about the threats posed by Redline Stealer, how it works, and how to protect your business.

What is Redline Stealer?

Redline Stealer is a lightweight yet highly dangerous infostealer malware designed to do one thing really well — steal. It targets your organization’s login data, stored payment details, corporate email accounts, and confidential documents. Plus, Redline Stealer collects sensitive information about an infected device’s software, antivirus programs, and active processes to aid in launching ransomware attacks.

Cybercriminals can simply buy Redline Stealer as a malware-as-a-service package on darknet forums. It’s inexpensive, highly customizable, and simple to deploy via phishing emails, fake software downloads, and malicious ads — wherever their victims least expect. Redline’s simple architecture has made it one of the most popular malware threats since its emergence in 2020.

Once on your system, Redline malware quietly extracts corporate data, system specs, and everything in between — all while making sure your cybersecurity team doesn't notice a thing until it’s too late. Attackers later sell this data to other hackers or use it for financial fraud.

How does Redline Stealer work?

The information-stealing Redline operates as a remote access trojan (RAT), which means that it disguises itself as a harmless file or program to trick unsuspecting users into installing it. Redline might be hidden in a phishing email, bundled software, or a seemingly innocent website link.

After Redline Stealer is installed, it connects to an open TCP port on a device and establishes a connection with the attacker’s computer. Next, the trojan connects to the command-and-control server controlled by the threat actors and gives intruders administrative access to your network. Once in an organization’s system, Redline malware can:

• Capture passwords.
• Steal cryptocurrency wallets.
• Spy on a network and log keystrokes.
• Steal sensitive information.
• Control webcams and record video or audio.
• Take screenshots.
• Spread other malware variants.
• Access, modify, download, or delete files.

What makes Redline particularly dangerous is that it runs quietly in the background and doesn’t appear in the list of running processes, which makes it really hard for system administrators to notice it.

How do cybercriminals acquire and deploy Redline Stealer?

Cybercriminals can easily buy Redline Stealer through underground forums and dark web marketplaces as a malware-as-a-service package available at surprisingly low prices. The malware comes with user-friendly dashboards and customizable options, easily accessible even to less tech-savvy attackers.

To deploy Redline Stealer, attackers embed it in phishing emails, fake software downloads, bogus system updates, or malicious ads. In this way, unsuspecting employees might unknowingly download the payload.

How do threat actors distribute Redline Stealer?

Cybercriminals use multiple sneaky and deceptive methods to distribute Redline Stealer onto unsuspecting users’ networks. One of the most common tactics is phishing emails loaded with malicious attachments or links disguised as legitimate communication. Attackers also embed software cracks, pirated software, and freeware downloads from disreputable websites with malware.

Threat actors also compromise ads, pop-ups, and websites that trigger Redline downloads when a user engages with them. Some attackers exploit weaknesses in outdated software to silently install the Redline malware onto the network. This information-stealing malware is very lightweight and highly adept at hiding, which is why it’s an absolute must to implement a strong cybersecurity strategy and monitor your business’s digital attack surface.

Indicators of a Redline Stealer infection

If your company network becomes infected with Redline Stealer, unusual network activity will likely be the first sign. For example, you may notice your system communicating with command-and-control servers, which will increase your network traffic. Other indications of Redline may include:

• Unusual system behavior. If your system gets sluggish out of nowhere, especially if you haven’t installed anything new or changed configurations, this could indicate that Redline is using your system resources.
• Strange network activity. Keep an eye on your company’s internet usage. Unusual amounts of data sent from your devices, especially at odd times, could indicate Redline exfiltrating your data to its command and control server.
• Unauthorized account logins. If you start receiving alerts about logins to your accounts from unfamiliar locations or devices, Redline malware could be the reason.
• Compromised autofill data. If your saved browser passwords stop working or you notice strange activity on accounts tied to saved autofill credentials, investigate further.
• Unfamiliar applications or files. Sometimes Redline Stealer disguises as legitimate software. If you spot any files, applications that you don’t remember downloading or installing, Redline could be doing it for you.
• Security software alerts. If your security solutions, such as antivirus, intrusion detection systems, or endpoint detection and response tools, alert intrusion, take it seriously.

How long does Redline Stealer stay in a system?

Redline Stealer malware stays in the system until it’s detected and removed. Unlike some other malware that causes immediate disruption, Redline is designed to quietly operate in the background, collecting data without detection. Unless your antivirus software detects it or you perform a thorough malware scan, it can remain active for months, or even longer. That’s why it’s crucial to regularly update your security software and practice vigilant online behavior — these are your best defenses against Redline and similar cyber threats.

How to remove Redline Stealer

If you suspect that your company device has been infected with Redline Stealer, react immediately to minimize potential damage. First, disconnect the device from the internet to prevent the malicious software from spreading and exfiltrating more information. Next, run a thorough system scan using a reliable antivirus software — it will remove Redline Stealer after it finds it.

Once the malware is out of your system, take some time to secure your accounts that may have been compromised. Change all passwords for your essential accounts, like email, banking, and cryptocurrency-related accounts. Plus, set up two-factor authentication where possible. And just to be really sure that the Redline is gone for good, check your browser extensions and remove any unfamiliar ones.

How to protect your organization from Redline Stealer malware

Establish a well-prepared cybersecurity strategy and vulnerability management plan to prevent Redline Stealer from carrying out data theft, account takeover attacks, financial fraud, or further spread of malware.

Conduct security awareness training

Teach your team how to recognize phishing attempts and suspicious links and introduce them to the dangers of downloading pirated software. A well-informed employee is your first line of defense. If people know what to look out for, they’re less likely to accidentally let Redline Stealer malware into the system.

Implement email and web filtering

Set up web filtering to block sketchy links and websites before they even reach your employees. Also, implement filtering tools that test suspicious files in a safe and isolated environment (sandbox) to check if they’re dangerous before letting them run on your system.

Deploy endpoint protection tools

Endpoint protection software uses behavior-based detection mechanisms that prevent malware, ransomware, and phishing attacks. It can detect new and sophisticated malware that usual security software might overlook. This smart tool monitors activity, detects suspicious behavior, and blocks anything harmful.

Regularly patch software and update asset inventory

Make sure your software and programs are up to date and patched against known vulnerabilities before attackers exploit them. Plus, an updated list of all your devices and software (your asset inventory) helps keep track of what you need to secure, patch, and monitor to minimize the attack surface. Staying proactive goes a long way.

Monitor the dark web and Telegram for your assets

NordStellar’s malware detection spots infostealers that bypass your antivirus or threat detection defenses. By using threat intelligence, it continuously monitors underground dark web forums and private Telegram channels for information tied to your company. These logs are a potential indicator of a compromised system — detailed packages of stolen data, ready for exploitation.

NordStellar identifies threats targeting your system, attributes them to known infostealer families, and alerts your security team, so they can start mitigating these threats, secure the network, and prevent a potential data breach.