cbcvebase.
CVE-2025-49706
published 2025-07-08

CVE-2025-49706: Improper authentication in Microsoft Office SharePoint allows an unauthorized attacker to perform spoofing over a network.

PriorityP188medium6.5CVSS 3.1
AVNACLPRNUINSUCLILAN
KEVITWEXPLOITRansomware
CISA Known Exploited Vulnerabilitydue 2025-07-23
Exploited in the wild
EPSS
99.88%
100.0th percentile
Improper authentication in Microsoft Office SharePoint allows an unauthorized attacker to perform spoofing over a network.

Affected

9 ranges
VendorProductVersion rangeFixed in
microsoftmicrosoft_sharepoint_enterprise_server_2016>= 16.0.0 < 16.0.5508.100016.0.5508.1000
microsoftmicrosoft_sharepoint_server_2019>= 16.0.0 < 16.0.10417.2002716.0.10417.20027
microsoftmicrosoft_sharepoint_server_subscription_edition>= 16.0.0 < 16.0.18526.2042416.0.18526.20424
microsoftsharepoint_enterprise_server
microsoftsharepoint_server< 16.0.18526.2042416.0.18526.20424
microsoftsharepoint_server
msrcmicrosoft_sharepoint_enterprise_server_2016
msrcmicrosoft_sharepoint_server_2019
msrcmicrosoft_sharepoint_server_subscription_edition

Detection & IOCsextracted from sources · hover to see the quote

filenameSpinstall0.aspx
urlc34718cbb4c6.ngrok-free[.]app/file.ps1
hash92bb4ddb98eeaf11fc15bb32e71d0a63256a0ed826a03ba293ce3a8bf057a514
pathC:\PROGRA~1\COMMON~1\MICROS~1\WEBSER~1\16\TEMPLATE\LAYOUTS\spinstall0.aspx
pathC:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\16\TEMPLATE\LAYOUTS\
url/_layouts/15/ToolPane.aspx?DisplayMode=Edit
url/_layouts/SignOut.aspx
url/_layouts/15/spinstall0.aspx
processw3wp.exe spawning encoded PowerShell
domainupdate.micfosoft[.]com
pathC:\Users\Administrator\Desktop\work\tools\ak47c2\dnsclinet-c\dnsclient\x64\Release\dnsclient.pdb
pathC:\Users\Administrator\Desktop\work\tools\ak47c2\httpclient-cpp\x64\Release\httpclient-cpp.pdb
snort
SID 65092
snort
SID 65183
yara
Asp.Webshell.SharpyShell-10056352-3
sigma
DeviceFileEvents | where FolderPath has "MICROS~1\\WEBSER~1\\16\\TEMPLATE\\LAYOUTS" | where FileName =~ "spinstall0.aspx" or FileName has "spinstall0" | project Timestamp, DeviceName, InitiatingProcessFileName, InitiatingProcessCommandLine, FileName, FolderPath, ReportId, ActionType, SHA256 | order by Timestamp desc
  • Detect ToolShell exploitation by monitoring IIS logs for POST requests to _layouts/15/ToolPane.aspx?DisplayMode=Edit with a Referer header of _layouts/SignOut.aspx — this is the authentication bypass pattern (CVE-2025-53771 / CVE-2025-49706).
  • Alert on creation of spinstall0.aspx (or any file matching 'spinstall0') under the SharePoint LAYOUTS directory as an indicator of web shell deployment.
  • Monitor for w3wp.exe (SharePoint IIS worker process) spawning encoded PowerShell child processes as a post-exploitation indicator.
  • Storm-2603's AK47HTTP backdoor sends JSON beacons with fields cmd, cmd_id, fqdn, result, type over HTTP with Content-Type: text/plain and Accept: */*; hunt for this unusual Content-Type in outbound HTTP from SharePoint servers.
  • Ransomware deployed by Storm-2603 uses DLL hijacking via legitimate binaries (MpCmdRun.exe, clink_x86.exe, VMToolsEng.exe); monitor for these processes loading unexpected DLLs.
  • Velociraptor version 0.73.4.0 (outdated, vulnerable to CVE-2025-6264) was installed on compromised servers for persistence by Storm-2603; detect unexpected Velociraptor installations on SharePoint or database servers.
  • The ToolShell exploit uses malicious __VIEWSTATE payloads signed with stolen ValidationKey/DecryptionKey from machineKey config; monitor for deserialization errors or anomalous ViewState sizes on SharePoint endpoints.
  • ·CVE-2025-49706 (spoofing) is the original vulnerability; CVE-2025-53771 is a bypass of its patch. In many reported cases it is unclear whether observed exploitation reflects the original CVE or its bypass variant.
  • ·These vulnerabilities affect on-premises SharePoint Server only (Subscription Edition, 2019, 2016, and EOL 2010/2013); SharePoint Online in Microsoft 365 is NOT impacted.
  • ·Existing Snort SID 65092 (published for CVE-2025-49704) has been confirmed by Talos to remain effective against the newer bypass variants CVE-2025-53770/53771 as well.
  • ·Patching alone is insufficient; Microsoft requires rotation of ASP.NET machine keys (ValidationKey/DecryptionKey) post-patch, as stolen keys can still be used for RCE even on patched servers.
  • ·Self-managed SharePoint Server instances hosted in cloud environments (Azure, AWS, GCP) are vulnerable; only SharePoint Online (Microsoft 365) is unaffected.

CVSS provenance

nvdv3.16.5MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
vulncheck8.8HIGH
cisa8.8HIGH
vendor_msrc9.8CRITICAL
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