cbcvebase.
CVE-2024-21413
published 2024-02-13

CVE-2024-21413: Microsoft Outlook Remote Code Execution Vulnerability

PriorityP196critical9.8CVSS 3.1
AVNACLPRNUINSUCHIHAH
KEVITWEXPLOITInitial access
CISA Known Exploited Vulnerabilitydue 2025-02-27
Exploited in the wild
EPSS
94.66%
99.8th percentile
Microsoft Outlook Remote Code Execution Vulnerability

Affected

12 ranges
VendorProductVersion rangeFixed in
microsoftmicrosoft_365_apps_for_enterprise>= 16.0.1 < https://aka.ms/OfficeSecurityReleaseshttps://aka.ms/OfficeSecurityReleases
microsoftmicrosoft_office_2016>= 16.0.0 < 16.0.5435.100116.0.5435.1001
microsoftmicrosoft_office_2019>= 19.0.0 < https://aka.ms/OfficeSecurityReleaseshttps://aka.ms/OfficeSecurityReleases
microsoftmicrosoft_office_ltsc_2021>= 16.0.1 < https://aka.ms/OfficeSecurityReleaseshttps://aka.ms/OfficeSecurityReleases
microsoftoffice_long_term_servicing_channel
msrcmicrosoft_365_apps_for_enterprise_for_32-bit_systems
msrcmicrosoft_365_apps_for_enterprise_for_64-bit_systems
msrcmicrosoft_office_2016
msrcmicrosoft_office_2019_for_32-bit_editions
msrcmicrosoft_office_2019_for_64-bit_editions
msrcmicrosoft_office_ltsc_2021_for_32-bit_editions
msrcmicrosoft_office_ltsc_2021_for_64-bit_editions

Detection & IOCsextracted from sources · hover to see the quote

sigma
Microsoft Outlook Malicious Moniker Link Remote Code Execution (CVE-2024-21413)
  • Detect emails containing hyperlinks using the file:// protocol with an exclamation mark inserted after the file extension (e.g., file:///\\<IP>\<path>\<file>.<ext>!<randomtext>), which is the Moniker Link bypass pattern for CVE-2024-21413.
  • The Preview Pane is an attack vector — exploitation can occur without the user clicking a link, so detections should not rely solely on click events; monitor Outlook preview activity for the same Moniker Link indicators.
  • ·The MkParseDisplayName() unsafe API is not exclusive to Outlook; any software using this API to parse attacker-controlled input may be vulnerable, broadening the attack surface beyond Outlook.
  • ·Microsoft initially (and mistakenly) flagged CVE-2024-21413 as exploited in the wild as a zero-day, then reverted that assessment; confirmed active exploitation was later added to CISA KEV catalog.

CVSS provenance

nvdv3.19.8CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
vulncheck9.8CRITICAL
cisa9.8CRITICAL
vendor_msrc9.8CRITICAL
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