SC-200 Respond to security incidents Practice Question
You are responding to an incident where a user's credentials were used to access a federated SaaS application from an IP address associated with a known threat actor. The user's account is not disabled. Which action is most effective to prevent further unauthorized access?
⚠ Common exam trap
A common mix-up: candidates choose to block the IP (Option B or D) because it seems immediate and technical, but they overlook that the attacker can easily change IPs and that the core issue is credential compromise, not network-level access.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Reset the user's password and revoke active sessions
Resetting the user's password and revoking active sessions immediately invalidates the compromised credentials and terminates any existing authenticated sessions, including the session used by the threat actor. This directly addresses the root cause—credential compromise—without unnecessarily disrupting the user's account permanently. In a federated SaaS scenario, password reset combined with session revocation ensures the threat actor cannot re-authenticate even if they possess the previous password hash or tokens.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Reset the user's password and revoke active sessions
Why this is correct
Resetting the password invalidates the attacker's knowledge of the compromised secret, while explicitly revoking the user's active sessions and refresh tokens terminates the attacker's existing authenticated access to Microsoft 365/Entra ID apps. This should be done before any other investigation step because it limits dwell time and prevents further lateral movement or data exfiltration as long as the attacker is not already using alternate backdoors. The 'Revoke user sessions' action in the Entra ID admin center (or Microsoft Graph `revokeSignInSessions`) closes current bearer/refresh tokens, not just the password-based login path.
- ✗
Create a Conditional Access policy to block the IP
Why it's wrong here
A Conditional Access policy that blocks the attacker's source IP does not revoke the user's existing sessions or refresh tokens, so the attacker's already-authenticated activity continues until tokens expire. The policy only applies at the next interactive sign-in attempt, and might take several minutes to propagate; in an active incident that delay allows continued unauthorized access. If the blocked IP is a cloud VPN or proxy, it can be replaced quickly, and the real threat is the compromised identity, not the egress address.
- ✗
Disable the user's account
Why it's wrong here
Disabling the user's account is a valid containment action but it is unnecessarily disruptive: the user loses all access to Microsoft 365 and is unable to work while the investigation runs, even if the compromise was limited to a single device or app. It also does not by itself invalidate access tokens that were already issued, so the attacker might continue to use those tokens until they expire unless you also perform a session revocation. In contrast, a password reset plus session revocation is targeted, removes the attacker's credential, and minimizes impact on the legitimate user.
- ✗
Block the source IP address on the firewall
Why it's wrong here
Firewall IP blocking operates at the network layer and is completely unaware of Entra ID authentication: if the attacker's credentials are valid, they can authenticate from any host, IP, or VPN endpoint. Attackers routinely cycle through proxies, cloud VPSes, or residential IP pools, and the blocked address is simply one egress path among many. Even if the block is applied to a firewall or a protection layer like Microsoft Sentinel, it does nothing to revoke the stolen password, tokens, or the attacker's foothold, so this action cannot be the primary response.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This SC-200 practice question is part of Courseiva's free Microsoft certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the SC-200 exam.