ORCA.189: Safe Attachments is not bypassed.
| ID | ORCA.189 |
| Severity | Medium |
| Suite | ORCA |
| Product | Defender |
| Related products | Exchange Online |
| Feature | Mail flow |
| Security area | Email and collaboration protection |
| Resource type | MailFlowRule |
| User impact of fixing | Low |
| Effort to fix | Medium |
| Framework controls | nist-800-53-r5:SI-3 Malicious Code Protection |
| MITRE ATT&CK | T1566.001, T1204.002 |
| Reads from | Exchange Online |
| Licence needed | ATP_ENTERPRISE |
What this checks and how to fix it
Section titled “What this checks and how to fix it”Microsoft Defender for Office 365 Safe Attachments assists scanning for zero day malware by using behavioural analysis and sandboxing, supplementing signature definitions. The protection can be bypassed using mail flow rules which set the X-MS-Exchange-Organization-SkipSafeAttachmentProcessing header for email messages.
Remediation action
Section titled “Remediation action”Remove mail flow rules which bypass Safe Attachments.
Related Links
Section titled “Related Links”Mito check, based on ORCA. Author: soulemike. Open-source licences.
Open-source licences. CIS Benchmark material © Center for Internet Security, Inc.; CISA SCuBA baselines are public domain (CC0).
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