Infostealers Aren’t Just a Big Corporation Problem: How to Keep Attackers Out of Your Environment

Infostealers Aren’t Just a Big Corporation Problem: How to Keep Attackers Out of Your Environment

Typically, when thinking of a cyberattack, your mind might go to malware signatures, suspicious emails, and antivirus alerts. Cybersecurity professionals know modern attacks are often much quieter than people expect. There are cyber-attacks that aren’t always so loud and obvious to the “naked eye”. These attackers can swiftly move IP addresses, rotate servers, and domain names to avoid being seen.

What Is an Infostealer?

Cisco defines information stealers or “infostealers” as malicious programs designed to collect personal and financial information from infected systems. Unlike ransomware, infostealers quietly collect credentials and sensitive data in the background, often sending it to attacker-controlled servers for resale or further exploitation. Typically, they infiltrate devices through phishing emails, compromised websites, fake software installers, or embedded scripts in Office documents or PDFs.

You Don’t Have to be a Fortune 500 Company to be Targeted

Assuming hackers only target big corporations with billions of dollars is a bad business move. It’s easier for hackers to target places like smaller hospitals, non-profit organizations, or law firms. These organizations often hold large amounts of sensitive data but may lack the large security teams, or advanced monitoring tools needed to detect threats quickly. Often these smaller organizations have a “cybersecurity team” of one person, and they often have additional non-cyber responsibilities. And while this person can be very diligent, there’s only so much one person can defend on their own.

Common Infostealer Tactics

Attackers are constantly changing tactics to avoid detection and remain inside environments longer. Instead of relying on the same infrastructure repeatedly, they move quickly and quietly to stay ahead of security teams.

- Rotating Domains
Cybercriminals frequently generate and swap domain names to avoid getting blocked. Even if one malicious domain gets flagged, dozens more may already be waiting in the background ready to take its place.

- Using “Bulletproof” Hosting Providers
Some attackers rely on hosting providers known for ignoring or overlooking suspicious activity. These services allow criminals to deploy malware, run phishing campaigns, and quickly relocate infrastructure when attention starts building.

- Blending Into Legitimate Services
Not every malicious file comes from an obviously suspicious website. Attackers often abuse trusted cloud platforms and content delivery services to host malware or stolen data, making malicious traffic appear more legitimate at first glance.

- Taking Advantage of Vulnerabilities
Hackers also look for weaknesses in commonly used software and systems. When vulnerabilities in platforms are exposed, attackers can quietly gain access, move through environments, and shift infrastructure before defenders notice unusual activity.

This constant movement makes detection difficult. Static blacklists and simple domain-blocking rules are no longer enough when attackers can rapidly change domains, servers, and delivery methods to stay hidden.

GO’s Top 10 Most Effective Defenses for Infostealers

1. Require phishing-resistant multifactor authentication (“MFA”) to ensure attackers cannot man-in-the-middle your MFA process.

2. Implement conditional access policies that block sign ins from unmanaged devices and block risky sign ins (e.g., impossible travel).

3. Use endpoint detection & response (“EDR” or “XDR”) with attack surface reduction (“ASR”) rules that block known suspicious behaviors

4. Block passwords from being stored in the user’s browser.

5. Prevent phishing emails & malicious attachments from landing in users’ email inboxes

6. Block execution from writable locations (e.g.,temp folders, downloads folder, user profile folders)

7. Use DNS filtering to block suspicious domainsand newly registered domains

8. Harden endpoints including patching targeted applications and disabling office macros

9. Train all users to recognize the signs of malicious activity and how to report it

10. Do not give users administrator privileges to their systems.

Building Cyber Resiliency

Cyber threats like infostealers aren’t going away, and they’re not slowing down. The organizations that stay ahead aren’t always the ones with the biggest budgets—they’re the ones that take a more proactive approach to security and understand where their risks are.

For many teams, especially those without large security staff or dedicated resources, that is where support becomes important. And we recognize that the Top 10 list above can seem overwhelming, and you may not know where to start. Go Security Pro can help your organization build layered defenses, strengthen visibility across your environment, and better understand where your biggest exposure points exist.