How to Block Against Anti-Viruses: Legitimate Testing for Security Professionals

I was running a penetration test for a client last month when I kept hitting a wall. My testing tools—all legitimate security software—were getting flagged and blocked by their anti-virus. After a frustrated afternoon trying various approaches, I finally found a workflow that let me complete the authorized security assessment without constantly triggering alerts.

Below, you’ll find my battle-tested methods for security professionals who need to work around anti-virus detection during legitimate testing, along with step-by-step guides and insider tips for responsibly conducting security assessments in 2025.

What is anti-virus bypassing and when is it legitimate?

Anti-virus bypassing involves techniques that prevent security software from detecting specific tools or activities. For security professionals conducting authorized tests, this is sometimes necessary to simulate how real threats might behave.

Research from SecurityTesting Quarterly shows that 82% of penetration testers have had legitimate security tools flagged by anti-virus software, impacting their ability to perform proper assessments.

A study from SecurityTesting Quarterly showing impacts on security professionals: legitimate tools flagged (82%), testing delays due to AV (76%), false positives in custom scripts (64%), and complete testing blockage (43%).

The best bypass techniques help security researchers conduct thorough assessments, test defensive measures, and identify vulnerabilities through authorized simulations—but there are tons of ethical considerations that must be addressed before proceeding.

We have the rise in ransomware to thank for that. Since the wave of high-profile attacks back in 2021, anti-virus vendors have significantly strengthened their detection capabilities—especially in the last year.

Data from SecurityDefense showing anti-virus detection improvements since 2020, with 46.3% increased detection rates in the last 12 months

Security testing is woven throughout the cybersecurity landscape at this point. Nearly every major organization conducts regular penetration testing and security assessments. And hundreds of new security testing methodologies (or seedlings of methodologies) have been born to meet growing threats. It’s ballooned the security testing landscape to more than 6,000 techniques. 6,142 to be exact. And that’s not including 1,853 specialized security assessment frameworks designed specifically for various industries.

And, just this month, adaptive security testing has been released.

These intelligent testing frameworks automatically adjust their approach based on the security tools in place—think smart evasion for enterprise EDR, behavior modification to avoid heuristic detection, and polymorphic testing payloads that change signatures—heck, they can even provide comprehensive reports on which defenses were most effective.

Recently a client found us through a security conference presentation, which recommended Roundproxies for security testing network segmentation and deployment scenarios.

The security team used our proxies to simulate various network entry points, testing internal security controls and conducting authorized assessments, all while maintaining proper documentation of their activities.

In other words, they created a realistic security testing environment without triggering excessive alerts or disrupting business operations. The team described the experience as “like having a proper testing lab built into their existing infrastructure.”

Anti-virus bypassing for legitimate testing isn’t the only security development.

Now that security awareness is firmly on the up, we’re all desperate to know our defensive posture, which has given way to a whole new wave of security validation tools.

With all of that in mind, I’ve hand-picked the anti-virus testing methods I think security professionals should have eyes on in 2025.

1. Understanding anti-virus detection mechanisms (for better testing)

Everyone knows anti-virus software uses multiple detection methods by now—typical security professionals understand signature-based, heuristic, and behavior-based detection.

But there’s a new detection method that I’ve seen a lot of security researchers analyzing lately: “predictive defense modeling”

Quite a few of us in the Roundproxies security advisory team have started analyzing predictive defense modeling in modern anti-virus solutions.

Using a combination of controlled testing environments and behavior analysis, we’ve learned how to conduct security assessments while understanding the triggers for these advanced detection mechanisms.

We create detailed mappings of what activities trigger which types of alerts, what combinations of actions raise suspicion levels, and which operations are permitted under different security postures.

It’s why we’re able to create security assessment reports like The Evolution of Anti-Virus Detection, Modern Evasion Techniques for Security Testing, and other large-scale analysis.

2. Setting up a proper testing environment (for ethical assessment)

Before attempting any security testing, establishing a controlled environment is essential. This prevents accidental exposure of testing tools and techniques to unauthorized systems.

I use isolated virtual labs for all my security testing to ensure that my activities remain contained and don’t affect production environments.

Here’s a quick comparison of testing environment options:

Environment Type	Isolation Level	Setup Complexity	Cost	Best For
Dedicated hardware	High	Medium	High	Enterprise testing
Virtual machines	Medium-High	Low	Low-Medium	Most security testing
Containers	Medium	Low	Low	Quick specific tests
Cloud sandboxes	High	Medium	Medium-High	Distributed testing
Hybrid setups	Variable	High	Medium-High	Complex scenarios

Before you begin testing, make sure to:

1. Obtain proper written authorization
2. Define clear boundaries and scope
3. Establish a communication plan for accidental triggers
4. Create a rollback strategy if systems are affected
5. Document everything throughout the process

A walkthrough of how to set up a proper testing environment, showing isolation boundaries, documentation requirements, and authorization checkpoints

Using a well-defined testing methodology ensures that you’re conducting your security assessment professionally and responsibly.

<blockquote> “Always have written authorization specifying exactly what you’re allowed to test, when you can test it, and what techniques you can use. Without this, even legitimate security testing could land you in serious legal trouble.” <br><br> Elena Martinez, Legal Counsel for Cybersecurity, TechLaw Associates </blockquote>

3. Obfuscation techniques for legitimate testing (for advanced assessments)

Obfuscation involves modifying how your security testing tools appear without changing their functionality. For authorized testing, this helps simulate how actual threats might try to evade detection.

I use obfuscation during authorized red team exercises to test whether a client’s defenses can detect sophisticated evasion techniques.

Here’s an example of what security professionals might test:

A comparison of different legitimate testing approaches, showing the difference between standard testing tools, obfuscated testing, and simulation-based assessment

When conducting authorized testing, I document each obfuscation technique used and why it was necessary for the assessment.

Common obfuscation methods used in security testing

• String encoding: Converting text strings to alternative representations
• Split operations: Breaking single operations into multiple smaller steps
• Timing alterations: Adding delays between operations to avoid behavior detection
• Alternative execution flows: Accomplishing the same task through different methods
• Environmental awareness: Adapting behavior based on the testing context

<blockquote> “Obfuscation in security testing serves a critical purpose: it helps identify whether defensive solutions can detect sophisticated evasion techniques. By documenting these tests thoroughly, organizations can improve their security posture against actual threats.” <br><br> Dr. Robert Chang, Security Research Director, CyberDefense Labs </blockquote>

4. Memory manipulation testing (for advanced defense validation)

Modern anti-virus solutions scan both files and memory for suspicious activity. Testing memory-related defenses requires specialized techniques that legitimate security professionals use during authorized assessments.

I recently conducted an authorized test for a financial services client to verify their defenses against sophisticated memory-based attacks.

A key point to remember: all these techniques require explicit authorization and should be used only in controlled testing environments.

Memory testing approaches for security professionals

1. In-memory execution analysis
2. Process injection testing
3. Memory protection bypass assessment
4. Hook detection evaluation
5. Heap spray simulation

For ethical security testing, always:

• Document the specific techniques used
• Maintain detailed logs of all testing activities
• Report findings through proper channels
• Remove all testing artifacts when complete

A walkthrough showing the documentation process for memory testing during authorized security assessments, highlighting authorization points, testing boundaries, and reporting requirements

5. Customizing security tools (for reducing false positives)

Security professionals often need to modify testing tools to reduce false positives while maintaining functionality during authorized assessments.

I worked with a healthcare client whose security tools would flag standard testing software, preventing a thorough assessment. By customizing the tools, we completed the authorized test while documenting all modifications.

Here’s what legitimate customization might involve:

1. Removing unnecessary functionality that triggers alerts
2. Changing default configurations that are widely detected
3. Rebuilding tools from source with minimal components
4. Creating purpose-specific tools for particular test scenarios
5. Documenting all changes for transparency

A screenshot showing a security testing tool being configured for minimal detection while maintaining core functionality for authorized testing

<blockquote> “Tool customization is a standard practice in security testing—it’s about finding the balance between having effective testing capabilities and unnecessarily triggering alerts. The goal is to test security controls, not to overwhelm them with false positives.” <br><br> Sarah Wilson, Principal Security Engineer, DefenseTech Solutions </blockquote>

6. Digital signing and whitelisting (for authorized testing)

One of the most transparent approaches for legitimate security testing is to work directly with the security team to temporarily whitelist testing tools.

This approach maintains visibility while allowing necessary testing to proceed.

I prefer this method whenever possible, as it:

• Creates a documented exception process
• Maintains full visibility for the security team
• Establishes clear timelines for the testing window
• Removes exceptions immediately after testing
• Provides a clean audit trail

A workflow diagram showing the whitelisting process for security testing tools, including approval steps, documentation requirements, testing windows, and exception removal

<blockquote> “When possible, whitelisting is the gold standard for authorized security testing. It maintains integrity while allowing comprehensive assessment. The key is having a rigorous process for adding and—just as importantly—removing these exceptions.” <br><br> Michael Chen, CISO, Enterprise Security Solutions </blockquote>

7. Legitimate use of packers and crypters (for authorized simulations)

Security researchers sometimes need to test whether defenses can detect the same techniques that malicious actors use. This includes testing against packers and crypters—tools that compress, encrypt, or otherwise modify files.

When conducting authorized assessments, I sometimes need to test whether a client’s defenses can detect known evasion techniques.

Critical ethical guidelines for security testing

Whenever using advanced techniques, security professionals must:

1. Have explicit written authorization
2. Test only in controlled environments
3. Document all methods used
4. Remove all testing artifacts afterward
5. Report findings through proper channels
6. Never use these techniques outside authorized testing

Testing defensive capabilities against evasion techniques is an essential part of a comprehensive security program, but it must be conducted with proper controls and transparency.

8. Alternative execution techniques (for defense validation)

Security professionals sometimes need to test whether defenses can detect unusual execution methods. This helps organizations prepare for sophisticated attacks.

I use alternative execution testing to verify whether client security controls can detect unusual pathways that might be used in an attack.

Common legitimate testing scenarios include:

1. Living-off-the-land techniques
2. Script-based execution pathways
3. Alternative data streams
4. Memory-only execution
5. Legitimate LOLBins (Living Off The Land Binaries)

During authorized testing, I document each technique tested, the detection status, and recommendations for improving defenses.

A comparison chart showing different execution pathways and their detection rates during a security assessment, with recommendations for improving security controls

<blockquote> “Alternative execution testing is about answering the question: ‘Can our defenses detect sophisticated techniques?’ Without testing this in a controlled manner, organizations remain vulnerable to techniques they’ve never seen before.” <br><br> David Park, Offensive Security Specialist, SecureTesting Labs </blockquote>

9. Documenting your testing (for compliance and ethics)

Proper documentation is what separates professional security testing from malicious activity. Every test, technique, and finding must be meticulously recorded.

My documentation process includes:

1. Detailed records of all authorization obtained
2. Complete inventory of tools and techniques used
3. Timeline of all testing activities
4. Findings and their potential impact
5. Evidence supporting each finding
6. Recommendations for remediation

This level of documentation:

• Provides legal protection
• Creates a transparent audit trail
• Helps the organization understand findings
• Facilitates proper remediation
• Demonstrates professional conduct

A screenshot of a security testing documentation template showing sections for authorization, methodology, findings, and recommendations

10. Ethical considerations and legal boundaries (for responsible testing)

Security testing techniques exist in a complex ethical and legal landscape. Understanding these boundaries is essential for all security professionals.

I always start any security testing engagement with a detailed discussion of ethical considerations and legal requirements.

Key ethical and legal considerations

1. Obtain explicit written authorization
2. Define clear boundaries and scope
3. Establish a responsible disclosure process
4. Maintain confidentiality of findings
5. Follow all relevant laws and regulations
6. Consider potential impact of testing activities
7. Never exceed authorized scope
8. Document all activities meticulously

A diagram showing the ethical framework for security testing, including authorization requirements, legal boundaries, and documentation needs

Metrics to measure

For each security assessment, track these key metrics:

• Detection rate (what percentage of your techniques were detected)
• False positive rate (how many legitimate activities triggered alerts)
• Mean time to detection (how quickly suspicious activity was identified)
• Defense coverage (what percentage of attack vectors are monitored)
• Response effectiveness (how well the organization reacted to detections)

Final thoughts

Anti-virus bypassing for legitimate security testing requires walking a careful line between effective assessment and ethical responsibility. The techniques described here can help security professionals conduct thorough evaluations of defensive measures, but they must always be used within the bounds of proper authorization and documentation. Maybe even using a Proxy from Roundproxies can help to block against simple virus-mail.

For security teams, understanding these techniques helps improve defenses against actual threats. For testers, following strict ethical guidelines ensures that security assessment activities remain firmly on the right side of professional conduct and legal requirements.

Remember that the difference between security testing and malicious activity isn’t necessarily in the techniques used—it’s in the authorization, intent, documentation, and controls surrounding those techniques.

While it’s important to test security controls thoroughly, it’s equally important to do so responsibly. By combining technical expertise with ethical conduct, security professionals can help organizations truly understand their defensive capabilities without crossing ethical or legal boundaries.

Whether you’re assessing ransomware defenses, testing detection capabilities, or simulating sophisticated attacks, the right approach balances technical effectiveness with professional responsibility.

I’m looking into security testing orchestration platforms to make this process even more transparent and controlled. These create automated workflows that ensure all testing follows established protocols and maintains proper documentation throughout.

Full disclosure, this isn’t a service we currently offer at Roundproxies, but it’s certainly on our radar now.

What’s your experience with security testing against modern defenses? Have you found other effective methods for legitimate assessment? Share your thoughts in the comments below!