Mean Time to Remediation (MTTR)

TL;DR

• MTTR represents the average time required to resolve a security vulnerability after identification, providing a direct measure of operational efficiency.
• To calculate MTTR, divide the total time spent fixing issues by the number of incidents.
• The goal is to minimize exposure time so attackers are less likely to exploit known gaps.
• The solution is to accelerate the process by automating everything from vulnerability detection to code fix generation, eliminating delays in manual ticket queues and ensuring faster remediation.

What is MTTR?

Mean Time to Remediation (MTTR) is a key cybersecurity metric that shows how quickly you respond to a known threat. It measures the time from when a vulnerability is found to when a fix is implemented.

While metrics like MTTD reflect detection speed, MTTR reveals your organization’s true remediation efficiency. Rapid detection must be matched by prompt resolution to contain risk exposure and support business continuity.

Why MTTR Matters

Cybercriminals operate faster than traditional development timelines, accelerating the demand for responsive security operations. Industry trends indicate that defense windows are shrinking.

• The 5-day exploit window: In 2025, the average Time to Exploit (TTE), the gap between when a vulnerability is made public and when it’s actively exploited, fell from 32 days to just 5 days (CyberMindr, 2025).
• Exploitation surge: Using vulnerabilities as a way in has increased by 34% this year and now causes 20% of all confirmed breaches.
• The Remediation lag: Attackers act in days, but organizations often take weeks. The median time to fix critical vulnerabilities in edge and VPN devices remains 32 days, leaving a significant risk window. Only 54% of flaws are ever fully patched (Verizon DBIR, 2025). Day Acceleration: The discovery of exploited zero-day vulnerabilities increased by 46% compared to last year. Attackers now weaponize these flaws within hours of identification (WithSecure Labs, 2025).
• High MTTR drives up business costs far beyond technical debt. In 2025, the average cost of a U.S. data breach is $4.4 million, mainly due to delayed response and regulatory penalties (IBM, 2025).
• Compliance penalties: Under rules such as DORA, long exposure times count as failures under operational resilience. Organizations with high MTTR now face mandatory reporting and large non-compliance fines. You cannot move faster than the exploit scripts; your defense is purely theoretical.

How to Calculate MTTR

MTTR is calculated by dividing the total time spent repairing a system by the number of repairs performed over a specific period.

The Formula

MTTR-formula

Calculation Example

Imagine your engineering team handled 4 incidents last month:

1. Incident A: Database outage (Fixed in 30 minutes)
2. Incident B: API failure (Fixed in 2 hours / 120 minutes)
3. Incident C: Cache error (Fixed in 15 minutes)
4. Incident D: Security patch (Fixed in 45 minutes)

• Total Repair Time: 30 + 120 + 15 + 45 = 210 minutes
• Number of Repairs: 4

MTTR-formula-calculation

This means, on average, it takes your team roughly 52 minutes to fix an issue once they start working on it.

Example in Practice

Consider two companies facing a critical security vulnerability (e.g., Log4Shell).

Company A (High MTTR):

• Process: Manual. Alerts go to email. An engineer has to manually SSH into servers to find the vulnerable jar files and patch them one by one.
• MTTR: 48 Hours.
• Result: Attackers have two full days to exploit the vulnerability. Data is likely compromised.

Company B (Low MTTR - using Plexicus to automate remediation):

• Process: Automated. The vulnerability is detected immediately. An automated playbook triggers to isolate affected containers and apply a patch or virtual firewall rule.
• MTTR: 15 Minutes.
• Result: The vulnerability is closed before attackers can launch a successful exploit.

Who Uses MTTR

• DevOps Engineers - To track the efficiency of their deployment and rollback pipelines.
• SREs (Site Reliability Engineers) - Ensure they meet SLAs (Service Level Agreements) for uptime.
• SOC Analysts - To measure how quickly they can neutralize active security threats.
• CTOs & CISOs - To justify investments in automation tools by showing a reduction in recovery time.

When to Apply MTTR

MTTR should be continuously monitored, but it is most critical during the Incident Response phase of the SDLC (Software Development Life Cycle)

• During Incidents: It acts as a live pulse check. “Are we fixing this fast enough?”
• Post-Mortem: After an incident, reviewing MTTR helps identify if the delay was caused by detecting the issue (MTTD) or fixing it (MTTR).
• SLA Negotiation: You cannot promise a customer “99.99% uptime” if your average MTTR is 4 hours.

Best Practices to Reduce MTTR

• Automate Everything: Manual fixes are slow and error-prone. Use Infrastructure as Code (IaC) to redeploy broken infrastructure rather than fixing it manually.
• Better Monitoring: You can’t fix what you can’t see. Granular observability tools help pinpoint the root cause faster, reducing the “diagnosis” portion of repair time.
• Runbooks & Playbooks: Have pre-written guides for common failures. If a database locks up, the engineer shouldn’t have to Google “how to unlock a database.”
• Blameless Post-Mortems: Focus on process improvement, not people. If engineers fear punishment, they might hide failures, making MTTR metrics inaccurate.

Related Terms

• MTTD (Mean Time To Detect)
• MTBF (Mean Time Between Failures)
• SLA (Service Level Agreement)
• Incident Management

Common Myths

• Myth: You can reach “zero vulnerabilities.”

  Reality: The goal is to fix critical issues fast enough to beat exploitation.

• Myth: More scanners equal better security.

  In reality, adding tools just creates more noise and manual work if not integrated.

• Myth: Security tools slow down developers.

  Reality: Security only slows developers down when it generates “broken” alerts. When you provide a pre-written pull request, you’re saving them hours of research.

FAQ

What is a “good” MTTR?

Top DevOps teams aim for an MTTR of under 24 hours for critical vulnerabilities.

How does MTTR differ from MTTD?

MTTD (Mean Time to Detect) shows how long a threat is present before you notice it. MTTR shows how long it remains after you’ve found it.

Can AI actually help with MTTR?

Yes. AI tools like Plexicus handle triage and suggest fixes, which typically account for 80% of the remediation process.

Final Thought

MTTR is the heartbeat of your security program. If it’s high, your risk is high. By automating the transition from finding issues to creating pull requests, you stop treating security as a bottleneck and start treating it as a normal part of your CI/CD pipeline.