CIS.M365.2.4.4: Ensure Zero-hour auto purge for Microsoft Teams is on (Only Checks ZAP is enabled)

CIS Benchmark notice

This check implements a recommendation of the CIS Microsoft 365 Foundations Benchmark. The benchmark text is © Center for Internet Security, Inc. and is not reproduced here beyond the short summary below. Get the full benchmark free of charge from cisecurity.org.

ID	CIS.M365.2.4.4
Severity	Medium
Suite	CIS Microsoft 365 Foundations Benchmark
Product	Defender
Related products	Teams
Feature	Zero-hour auto purge
Security area	Email and collaboration protection
Resource type	Tenant
User impact of fixing	Low
Effort to fix	Low
Benchmark	CIS Microsoft 365 Foundations Benchmark 7.0.0, 2.4.4 (L1, E5 Level 1)
Framework controls	cis-m365:2.4.4 nist-800-53-r5:SI-3 Malicious Code Protection
MITRE ATT&CK	T1566
Reads from	Microsoft Teams
Licence needed	THREAT_INTELLIGENCE

What this checks and how to fix it

2.4.4 (L1) Ensure Zero-hour auto purge for Microsoft Teams is on

Zero-hour auto purge (ZAP) is a protection feature that retroactively detects and neutralizes malware and high confidence phishing. When ZAP for Teams protection blocks a message, the message is blocked for everyone in the chat. The initial block happens right after delivery, but ZAP occurs up to 48 hours after delivery.

Rationale

ZAP is intended to protect users that have received zero-day malware messages or content that is weaponized after being delivered to users. It does this by continually monitoring spam and malware signatures taking automated retroactive action on messages that have already been delivered.

Impact

As with any anti-malware or anti-phishing product, false positives may occur

Remediation action

To enable Zero-hour auto purge for Microsoft Teams:

1. Navigate to Microsoft 365 Defender
2. Click to expand System select Settings > Email & collaboration > Microsoft Teams protection
3. Set Zero-hour auto purge (ZAP) to On (Default).

PowerShell

1. Connect to Exchange Online using Connect-ExchangeOnline.
2. Run the following cmdlet:

Set-TeamsProtectionPolicy -Identity "Teams Protection Policy" -ZapEnabled $true

Related links

• Microsoft 365 Admin Center
• Zero-hour auto purge (ZAP) in Microsoft Teams
• Configure ZAP for Teams protection in Defender for Office 365
• CIS Microsoft 365 Foundations Benchmark v7.0.0 - Page 157

---

Mito check, based on CIS Microsoft 365 Foundations Benchmark. Author: NZLostboy; contributors: Korthal-Maiyn. Open-source licences.