Antivirus (AV) solutions are the first line of defense against malware threats, offering essential protection against known attacks. Many organizations adopt AV multi-scanning, using multiple AV engines to increase detection rates and reduce reliance on any single vendor. But is more always better?
This article explores the pros and cons of AV multi-scanning, the tradeoffs involved, and the optimal approach to achieving high security without unnecessary overhead.
The Advantage of Multiple AV Scan Engines
The primary benefit of multi-scanning is improved malware detection. Since no single AV engine is perfect, using multiple independent scanners increases the likelihood of catching newly discovered threats.
Here’s why organizations consider multi-scanning:
- Higher detection rates – The more engines you use, the better your chances of identifying malware.
- Coverage for diverse threat types – Some AVs specialize in signature-based detection, while others use heuristic, AI-driven, or behavioral analysis.
- Minimization of blind spots – Certain malware may evade detection by one AV engine but be caught by another.
However, while more AV engines theoretically improve detection rates, the actual gains quickly diminish after a certain threshold.
For instance, combining two independent AV engines significantly reduces undetected malware. But increasing this number to five, ten, or more engines results in only marginal improvements while introducing new challenges.
The Downside of Adding More AV Engines
More engines don’t just mean better security—they also introduce major tradeoffs:
1. Higher False Positive Rates
False positives—when a file is wrongly flagged as malware—increase exponentially as more AV engines are used. This can result in:
- Unnecessary alerts that disrupt workflow
- Legitimate files getting quarantined or deleted
- Increased burden on IT teams to investigate false alarms
2. Performance & Latency Issues
Running multiple AV engines requires more computing resources, leading to:
- Slower file scanning and processing times
- Increased CPU and memory usage, impacting overall system performance
- Longer response times in security operations
3. Security Tradeoffs & Operational Complexity
When using many AV engines, organizations often apply quorum-based decision models, requiring multiple engines to agree before taking action. This can backfire by:
- Allowing real malware to slip through when consensus isn’t reached
- Delaying threat response due to conflicting AV decisions
In extreme cases, organizations may even disable certain AV alerts to reduce noise—defeating the entire purpose of multi-scanning!
What’s the Optimal Number of AV Engines?
Finding the right balance between detection rates, false positives, and system performance is critical. Based on independent AV test results, the ideal multi-scanning strategy should:
- Use a select number of engines (typically 3-5) that complement each other
- Incorporate different detection technologies (e.g., signature-based, heuristic, AI-driven, sandboxing)
- Avoid unnecessary duplication—many AV solutions share core signature databases, making additional engines redundant
- Ensure that AV vendors are trustworthy and not from high-risk geopolitical regions
For example, a well-balanced multi-scanning approach using 5 independent engines can achieve high detection rates without the excessive false positives and performance issues seen with 10+ engines.
Beyond AV: Why Prevention Matters More
Even the best AV multi-scanning setup has limitations. Traditional AV engines rely on detection-based methods, meaning they can still miss:
- Zero-day threats (new malware with no known signature)
- Polymorphic malware (viruses that constantly change to evade detection)
- Fileless attacks that don’t leave a traditional malware signature
A more effective security approach involves:
- AI-driven behavioral analysis to detect anomalies
- Content Disarm and Reconstruction (CDR) to eliminate potential threats rather than detect them
- Whitelisting-based strategies to allow only known-good files
By shifting from detection to prevention, organizations can avoid the AV multi-scanning arms race while enhancing security posture.
Finding the Right Balance: Key Takeaways
While multi-scanning AV engines can enhance detection rates, the diminishing returns, increased false positives, and operational complexity mean that more isn’t always better.
A strategic approach to multi-scanning should prioritize:
- Using 3-5 carefully selected AV engines rather than 10+
- Ensuring diversity in detection methods (signature, AI, heuristics, CDR)
- Avoiding redundant or low-quality AV solutions
- Focusing on prevention-based security rather than detection alone
By adopting this balanced security strategy, organizations can maximize malware protection without unnecessary tradeoffs.
