cbcvebase.
CVE-2022-41040
published 2022-10-03

CVE-2022-41040: Microsoft Exchange Server Elevation of Privilege Vulnerability

PriorityP197high8.8CVSS 3.1
AVNACLPRLUINSUCHIHAH
KEVITWEXPLOITRansomwareInitial access
CISA Known Exploited Vulnerabilitydue 2022-10-21
Exploited in the wild
EPSS
99.94%
100.0th percentile
Microsoft Exchange Server Elevation of Privilege Vulnerability

Affected

13 ranges
VendorProductVersion rangeFixed in
microsoftexchange_server
microsoftexchange_server
microsoftexchange_server
microsoftmicrosoft_exchange_server_2013_cumulative_update_23>= 15.00.0 < 15.00.1497.04415.00.1497.044
microsoftmicrosoft_exchange_server_2016_cumulative_update_22>= 15.0.0 < 15.01.2375.03715.01.2375.037
microsoftmicrosoft_exchange_server_2016_cumulative_update_23>= 15.01.0 < 15.01.2507.01615.01.2507.016
microsoftmicrosoft_exchange_server_2019_cumulative_update_11>= 15.02.0 < 15.02.0986.03615.02.0986.036
microsoftmicrosoft_exchange_server_2019_cumulative_update_12>= 15.02.0 < 15.02.1118.02015.02.1118.020
msrcmicrosoft_exchange_server_2013_cumulative_update_23
msrcmicrosoft_exchange_server_2016_cumulative_update_22
msrcmicrosoft_exchange_server_2016_cumulative_update_23
msrcmicrosoft_exchange_server_2019_cumulative_update_11
msrcmicrosoft_exchange_server_2019_cumulative_update_12

Detection & IOCsextracted from sources · hover to see the quote

ip45.76.141.84
ip45.76.143.143
ip179.60.149.28
ip104.244.79.6
ip185.220.101.182
ip137.184.67.33
ip103.9.76.208
urlhttps://{exchange_host}/owa/{email_address>/powershell
pathC:\Program Files\Microsoft\Exchange Server\V15\Logging\CmdletInfra\Powershell-Proxy\Http\
commandGet-ChildItem -Recurse -Path -Filter "*.log" | Select-String -Pattern 'powershell.*autodiscover\.json.*\@.*200'
processw3wp.exe -> cmd.exe (China Chopper webshell activity)
port8080
  • Search IIS logs for autodiscover.json requests chained with PowerShell returning HTTP 200, indicative of CVE-2022-41040 SSRF exploitation attempts.
  • Detect China Chopper webshell activity by monitoring for w3wp.exe spawning processes with command lines containing &ipconfig&echo, &whoami&echo, &echo [E], or &echo [S].
  • Detect suspicious file writes (EXE/DLL) to C:\Users\Public\ on Exchange hosts where w3wp.exe is present, indicating post-exploitation staging.
  • Detect suspicious file creation in Exchange FrontEnd\HttpProxy directories by w3wp.exe processes with MSExchange in the command line.
  • Detect certutil making outbound connections to public IPs on port 8080, which may indicate post-exploitation connectivity checks in Exchange 0-day attacks.
  • The OWASSRF exploit method targets the OWA endpoint directly (POST to /owa/{email}/powershell) rather than autodiscover, bypassing the URL rewrite mitigation pattern (?=.*autodiscover)(?=.*powershell).
  • Monitor Exchange Remote PowerShell logs at C:\Program Files\Microsoft\Exchange Server\V15\Logging\CmdletInfra\Powershell-Proxy\Http\ for signs of exploitation.
  • Track attacker IPs associated with ProxyNotShell exploitation; 137.184.67.33 was identified as a C2 server in GTSC's investigation.
  • Monitor for PowerShell spawned as a child of IIS (w3wp.exe) as an indicator of CVE-2022-41082 RCE execution.
  • ·The URL rewrite mitigation pattern (?=.*autodiscover)(?=.*powershell) is NOT effective against the OWASSRF exploit method, which routes requests directly through the OWA endpoint instead of autodiscover.
  • ·Exploitation requires authenticated access with at minimum standard user credentials; Exchange Online customers are not affected.
  • ·CVE-2022-41040 affects only on-premises Exchange Server 2013, 2016, and 2019; Exchange Online is not affected.
  • ·Ensure X-Forwarded-For header is configured to log true external IP addresses for requests to proxied services, otherwise attacker IPs may not be visible in logs.

CVSS provenance

nvdv3.18.8HIGHCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
vulncheck8.8HIGH
cisa8.8HIGH
vendor_msrc8.8HIGH
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