Elastic Security Detection Rules

Unusual Web Config File Access

Last updated 14 days ago on 2025-08-04
Created a month ago on 2025-07-23

About

Detects unusual access to the web.config file, which contains sensitive credential information such as database connection strings, machineKey validation/decryption keys, and SAML/OAuth token settings. Attackers can use the information extracted to forge malicious __VIEWSTATE requests for persistent RCE on the web server or pivot to the SQL server using exposed connection strings.
Tags
Domain: EndpointOS: WindowsUse Case: Threat DetectionTactic: Credential AccessData Source: Elastic DefendLanguage: kuery
Severity
medium
Risk Score
47
MITRE ATT&CK™

Credential Access (TA0006)(opens in a new tab or window)

↳ OS Credential Dumping (T1003)(opens in a new tab or window)

License
Elastic License v2(opens in a new tab or window)

Definition

Rule Type
New Terms Rule
Integration Pack
Prebuilt Security Detection Rules
Index Patterns
logs-endpoint.events.file-*
Related Integrations

endpoint(opens in a new tab or window)

Query
event.category:file and host.os.type:windows and event.action:open and
  file.name:"web.config" and file.path : *VirtualDirectories*

Install detection rules in Elastic Security

Detect Unusual Web Config File Access in the Elastic Security detection engine by installing this rule into your Elastic Stack.

To setup this rule, check out the installation guide for Prebuilt Security Detection Rules(opens in a new tab or window).