cbcvebase.
CVE-2019-1257
published 2019-09-11

CVE-2019-1257: A remote code execution vulnerability exists in Microsoft SharePoint when the software fails to check the source markup of an application package, aka…

PriorityP358high8.8CVSS 3.1
AVNACLPRLUINSUCHIHAH
EPSS
11.66%
95.6th percentile
A remote code execution vulnerability exists in Microsoft SharePoint when the software fails to check the source markup of an application package, aka 'Microsoft SharePoint Remote Code Execution Vulnerability'. This CVE ID is unique from CVE-2019-1295, CVE-2019-1296.

Affected

11 ranges
VendorProductVersion rangeFixed in
microsoftmicrosoft_sharepoint_enterprise_server
microsoftmicrosoft_sharepoint_foundation
microsoftmicrosoft_sharepoint_server
microsoftsharepoint_enterprise_server
microsoftsharepoint_foundation
microsoftsharepoint_foundation
microsoftsharepoint_server
msrcmicrosoft_sharepoint_enterprise_server_2016
msrcmicrosoft_sharepoint_foundation_2010_service_pack_2
msrcmicrosoft_sharepoint_foundation_2013_service_pack_1
msrcmicrosoft_sharepoint_server_2019

Detection & IOCsextracted from sources · hover to see the quote

processcmd.exe
processwin32calc.exe
processw3wp.exe
  • Detect BDC model uploads containing parameters of type Microsoft.BusinessData.Runtime.DynamicType, which triggers arbitrary XmlSerializer deserialization and is the core exploit primitive for CVE-2019-1257.
  • Monitor SharePoint Central Administration upload activity for Business Data Connectivity (BDC) model files, particularly via the path: Application Management > Manage service applications > Business Data Connectivity Service, or via PowerShell BDC model imports.
  • Alert on child processes (e.g., cmd.exe, calc.exe) spawned from w3wp.exe in the context of the SharePoint application pool, which indicates successful exploitation of this deserialization vulnerability.
  • Set breakpoint or monitor calls to System.Web.UI.ObjectStateFormatter.Deserialize within w3wp.exe as an indicator of deserialization exploitation in SharePoint.
  • Exploitation requires a user to upload a specially crafted SharePoint application package; monitor SharePoint for unexpected or unauthorized application package uploads as a precursor indicator.
  • ·Exploitation requires an administrator account to first upload a malicious BDC model to the SharePoint Business Data Connectivity Service; the attacker then invokes the method with a deserialization payload. This is a two-stage attack requiring elevated initial access.
  • ·The Preview Pane is not an attack vector for this vulnerability.
  • ·Vulnerability was confirmed on Microsoft SharePoint Server 2016 with KB4464594 installed on 64-bit Windows Server 2016 update 14393.3025; all supported SharePoint versions are affected.

CVSS provenance

nvdv3.18.8HIGHCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
nvdv2.06.5MEDIUMAV:N/AC:L/Au:S/C:P/I:P/A:P
vendor_msrc8.8CRITICAL
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