T1056.003_web-portal-capture

T1056.003 Web Portal Capture

Sub-technique of: T1056

High-Level Description

Adversaries may install code on externally facing portals, such as a VPN login page, to capture and transmit credentials of users who attempt to log into the service. For example, a compromised login page may log provided user credentials before logging the user in to the service.

This variation on input capture may be conducted post-compromise using legitimate administrative access as a backup measure to maintain network access through External Remote Services and Valid Accounts or as part of the initial compromise by exploitation of the externally facing web service.

Kill Chain Phase

• Collection (TA0009)
• Credential Access (TA0006)

Platforms: Linux, macOS, Windows

What to Check

• Identify if Web Portal Capture technique is applicable to target environment
• Check Linux systems for indicators of Web Portal Capture
• Check macOS systems for indicators of Web Portal Capture
• Check Windows systems for indicators of Web Portal Capture
• Verify mitigations are bypassed or absent (1 known mitigations)
• Assess detection coverage (1 detection strategies)

How to Test

Manual Testing

1. Identify Attack Surface: Determine if the target environment is susceptible to Web Portal Capture by examining the target platforms (Linux, macOS, Windows).

2. Assess Existing Defenses: Review whether mitigations for T1056.003 are in place. If defenses are absent or misconfigured, this technique may be exploitable.

3. Execute Test: Use tools and methods described in the MITRE ATT&CK page and external references below.

Note: No Atomic Red Team tests available for this technique. See Atomic Red Team GitHub for updates.

Remediation Guide

M1026 Privileged Account Management

Do not allow administrator accounts that have permissions to modify the Web content of organization login portals to be used for day-to-day operations that may expose them to potential adversaries on unprivileged systems.

Detection

Detection of Credential Harvesting via Web Portal Modification

Risk Assessment

CWE Categories

References

• Volexity Virtual Private Keylogging
• Atomic Red Team - T1056.003
• MITRE ATT&CK - T1056.003