cbcvebase.
CVE-2017-8540
published 2017-05-26

CVE-2017-8540: The Microsoft Malware Protection Engine running on Microsoft Forefront and Microsoft Defender on Microsoft Windows Server 2008 SP2 and R2 SP1, Windows 7 SP1…

PriorityP187high7.8CVSS 3.1
AVLACLPRNUIRSUCHIHAH
KEVITWEXPLOIT
CISA Known Exploited Vulnerabilitydue 2022-03-24
Exploited in the wild
EPSS
71.96%
99.4th percentile
The Microsoft Malware Protection Engine running on Microsoft Forefront and Microsoft Defender on Microsoft Windows Server 2008 SP2 and R2 SP1, Windows 7 SP1, Windows 8.1, Windows Server 2012 Gold and R2, Windows RT 8.1, Windows 10 Gold, 1511, 1607, and 1703, and Windows Server 2016, Microsoft Exchange Server 2013 and 2016, does not properly scan a specially crafted file leading to memory corruption. aka "Microsoft Malware Protection Engine Remote Code Execution Vulnerability", a different vulnerability than CVE-2017-8538 and CVE-2017-8541.

Affected

15 ranges
VendorProductVersion rangeFixed in
microsoftexchange_server
microsoftexchange_server
microsoftforefront_endpoint_protection
microsoftmalware_protection_engine<= 1.1.13704.0
microsoftmalware_protection_engine>= 1.1.13701.0 < 1.1.13704.01.1.13704.0
microsoft_corporationmalware_protection_engine
msrcmicrosoft_endpoint_protection
msrcmicrosoft_exchange_server_2013
msrcmicrosoft_exchange_server_2016
msrcmicrosoft_forefront_endpoint_protection
msrcmicrosoft_forefront_endpoint_protection_2010
msrcmicrosoft_security_essentials
msrcmicrosoft_system_center_endpoint_protection
msrcwindows_defender
msrcwindows_intune_endpoint_protection

Detection & IOCsextracted from sources · hover to see the quote

urlhttps://gitlab.com/exploit-database/exploitdb-bin-sploits/-/raw/main/bin-sploits/42088.zip
versionmpengine.dll <= 1.1.13701.0
filenamempengine.dll
  • Trigger condition: a specially crafted file delivered via web, email, IM, or user-uploaded content is scanned by an affected version of mpengine.dll (≤ 1.1.13701.0); no user interaction beyond delivery is required when real-time protection is enabled.
  • The exploit PoC zip is password-protected with the password 'nscriptgc'; detection of this specific password on archive files submitted to or scanned by Defender/MsMpEng is a strong indicator of exploit delivery.
  • Exploitation results in code execution as LocalSystem; monitor for unexpected child processes or privilege escalation originating from MsMpEng.exe (the Malware Protection Engine host process).
  • Verify mpengine.dll version on all endpoints; any version at or below 1.1.13701.0 is vulnerable. The patched version is 1.1.13704.0 or later.
  • ·Windows Server 2008 R2 systems are NOT affected if the Desktop Experience feature is not installed — scope detection rules accordingly.
  • ·The GC-disable flag (blockGC) passed to JsTree::run is frame-local, not global; a nested eval() in a valueOf/toString callback can bypass it and trigger a global GC, meaning detection logic must account for nested JsTree execution contexts.
  • ·The inline string optimisation in MsMpEng's JS engine means toString must return a string of more than three characters to avoid the optimisation path and reach the vulnerable code; PoC strings shorter than 4 chars will not trigger the UAF.

CVSS provenance

nvdv3.17.8HIGHCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
nvdv2.09.3CRITICALAV:N/AC:M/Au:N/C:C/I:C/A:C
vulncheck7.8HIGH
cisa7.8HIGH
vendor_msrc7.8CRITICAL
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