A managed security service provider (MSSP) takes on agreed, ongoing cyber security tasks for your business, such as monitoring threats, managing protective controls and responding to suspicious activity. You are paying for people and processes around security tools, not simply another software subscription.
The distinction matters when something goes wrong. A service that emails an alert is different from one that investigates it, calls the right person and has permission to isolate an affected device. The contract should make those differences clear before an incident happens.
What you are buying beyond security software
An MSSP can supplement an internal IT team or work alongside an outsourced IT support company. Its remit might cover endpoints, email and cloud accounts, network devices or a combination of these. Coverage depends on the systems included in the agreement and the information the provider can collect from them.
The practical value is consistent ownership: someone reviews security events, maintains agreed controls and follows a response process. That does not automatically mean round-the-clock human monitoring, unlimited incident response or responsibility for every application.
Before comparing quotes, establish what you need protected, who currently manages it and what would cause the greatest business disruption. A manufacturer with production systems has different priorities from a professional services firm that relies mainly on Microsoft 365.
What a managed security service provider actually does
Identify weaknesses and agree fixes
An initial assessment should establish the agreed scope: devices, user accounts, applications and critical data. Ongoing vulnerability management then helps identify exposed services, missing updates and insecure settings.
Finding a weakness is not the same as fixing it. Your agreement should specify who approves changes, who applies patches and how urgent issues are escalated when systems cannot be updated immediately.
Vulnerability scanning is also different from penetration testing, which tests systems from an attacker's perspective. Ask which activities are included, how often they happen and who verifies that identified weaknesses have been fixed.
Monitor systems and investigate alerts
Monitoring may draw on device alerts, identity sign-ins, email events and network logs. Visibility depends on supported integrations, configuration and any required licences.
Endpoint detection and response (EDR) helps identify suspicious activity on devices. Security information and event management (SIEM) brings logs together for analysis. These are tools; they do not, by themselves, guarantee that someone is investigating an alert.
A managed security service provider should explain how it distinguishes a genuine threat from routine activity, what evidence analysts review and when your team will be contacted. It should also explain what happens when essential logs stop arriving, because missing data can create blind spots.
Contain incidents and support recovery
If an alert is confirmed as malicious, the next step may be isolating a device, blocking a connection or disabling a compromised account. Whether the provider can act immediately depends on agreed permissions.
Check whether the service includes active containment, investigation and recovery support, or only recommendations to your IT team. Large-scale forensic work, legal advice and out-of-hours recovery may need separate arrangements.
Recovery also involves restoring business operations safely. Backups need protection and restore testing, but an MSSP does not necessarily manage them. Identify who checks that the original weakness has been addressed before systems return to use.
Keep agreed controls working
Security settings drift as employees join, software changes and exceptions accumulate. Depending on scope, ongoing work can include checking endpoint protection, reviewing privileged access and maintaining agreed email or cloud security settings.
Reports should turn that work into decisions. Useful measures include unresolved high-risk weaknesses, overdue actions, gaps in monitoring coverage and progress on previous recommendations.
The NCSC's small business guide provides a useful baseline for measures such as updates, account protection and backups. A managed security service provider should show how its work supports those basics, rather than treating a dashboard full of blocked threats as proof that everything is secure.
An example: a compromised Microsoft 365 account
In this illustrative example, a finance employee's Microsoft 365 account is compromised. Assume the service includes identity monitoring and the provider is authorised to take urgent containment action.
An unusual sign-in generates an alert. An analyst checks the context, looks for suspicious activity and contacts the named business representative. If compromise is confirmed, authorised actions might include disabling access, revoking sessions and removing malicious mailbox forwarding rules.
The investigation must then establish what the attacker accessed or changed. Your finance team may need to verify payment instructions, while IT checks related accounts and restores safe access. Detection alone would not complete that job.
This is why service boundaries matter. If the provider can see device alerts but not Microsoft 365 activity, the incident may fall outside its monitoring coverage. If it needs approval before disabling an account, an unreachable contact can delay containment.
The key question is whether the managed security service provider can move from detection to an agreed action, with a clear route to someone authorised to make decisions.
MSSP, MSP and MDR: how the terms differ
These labels overlap, so compare responsibilities rather than names. A security operations centre (SOC), for example, describes a team or function rather than a guarantee of any particular service scope.
| Term | Main role | What to verify |
|---|---|---|
| MSP, managed service provider | Manages IT operations such as support, maintenance and infrastructure | Which security responsibilities are included |
| MSSP, managed security service provider | Delivers agreed ongoing security management services | Systems covered, monitoring hours and response authority |
| MDR, managed detection and response | Focuses on detecting, investigating and responding to threats | What response actions are included and who performs them |
| SOC, security operations centre | Provides the people and processes that monitor and handle security events | Staffing hours, escalation procedures and access to relevant data |
An MSSP may offer MDR within a wider package, while an MSP may deliver security through a specialist partner. Ask who performs the work and who is accountable when an issue crosses between suppliers.
What stays your responsibility?
Outsourcing security work does not outsource business accountability. Your organisation still needs to decide which risks it will accept, approve disruptive changes and provide accurate information about its systems.
Someone must own staff access, supplier relationships and business continuity decisions. These responsibilities should sit within your wider IT security strategy, with named deputies available when the usual decision-maker is absent.
Legal reporting duties also need a clear owner. For a notifiable personal data breach, the UK GDPR requires the controller to notify the ICO without undue delay and, where feasible, within 72 hours of becoming aware of it. The ICO's personal data breach guidance explains the reporting requirements. Not every security incident is a reportable personal data breach.
A provider can supply evidence and technical support, but your organisation needs a process for making that assessment and obtaining appropriate advice.
Questions to ask before signing a contract
Ask a prospective managed security service provider to walk through a realistic incident involving your business. A worked example often reveals more than a feature list.
Use these questions to clarify the agreement:
- What is covered? Confirm the devices, cloud services, sites and accounts included, along with exclusions and any licence dependencies.
- When are people available? Distinguish automated monitoring from staffed investigation, out-of-hours escalation and active response.
- What can you do without approval? Agree authority for actions such as isolating devices or disabling accounts, including exceptions for critical systems.
- What do response targets measure? Separate acknowledgement, investigation and containment. A fast acknowledgement is not the same as stopping an attack.
- What costs extra? Check incident response limits, forensic support, onsite work, recovery assistance and changes to the supported environment.
- How is information handled? Establish who can access your data, where relevant logs are stored, how long evidence is retained and what happens when the contract ends.
Also ask for an example report. It should make outstanding risks, owners and deadlines understandable to your business, not just show activity totals. Where another IT supplier must apply fixes, agree how tickets are handed over and who checks completion.
What affects the cost?
There is no meaningful universal price for a managed security service provider without knowing the scope. Pricing may depend on user or device numbers, supported systems, monitoring hours, security licences and the depth of response included.
The condition of your existing environment also matters. Initial work may be needed to configure logging, remove unsupported software or standardise protective controls before ongoing monitoring becomes effective.
Compare the full cost of achieving the same outcome. A cheaper monitoring-only service may leave your team responsible for investigation and containment. A broader service may include more of that work, but still exclude major incident recovery. Request a clear separation between onboarding, recurring charges and additional services.
Frequently asked questions
Is an MSSP the same as an IT support company? Not necessarily. IT support usually focuses on keeping systems usable and resolving operational problems. An MSSP focuses on agreed security responsibilities. One company can provide both, but the scope and handover between those functions should be explicit.
Does every MSSP provide 24/7 monitoring? No. Service hours vary. Even when monitoring runs continuously, human investigation or response may operate on a different schedule. Check what happens overnight, at weekends and on bank holidays, including who receives urgent calls.
Will a managed security service provider make us compliant? It can help implement controls and provide evidence, but buying a service does not establish compliance on its own. Your organisation still needs appropriate policies, governance, staff practices and decisions about how personal or regulated data is handled.
Establish the right division of responsibility
CIS provides managed IT support, cyber security, backup and recovery planning, Microsoft 365 and cloud services for UK organisations.
If you are reviewing outsourced security, speak to CIS about your IT and cyber security requirements. Start with the systems you rely on, the work your team can realistically handle and the response you would need during an incident. Those details provide a stronger basis for choosing a service than a list of tools.
