T1505 Server Software Component

High-Level Description

Adversaries may abuse legitimate extensible development features of servers to establish persistent access to systems. Enterprise server applications may include features that allow developers to write and install software or scripts to extend the functionality of the main application. Adversaries may install malicious components to extend and abuse server applications.

Kill Chain Phase

• Persistence (TA0003)

Platforms: Windows, Linux, macOS, Network Devices, ESXi

What to Check

• ] Identify if Server Software Component technique is applicable to target environment
• ] Check Windows systems for indicators of Server Software Component
• ] Check Linux systems for indicators of Server Software Component
• ] Check macOS systems for indicators of Server Software Component
• ] Verify mitigations are bypassed or absent (7 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 Server Software Component by examining the target platforms (Windows, Linux, macOS).

1. Assess Existing Defenses: Review whether mitigations for T1505 are in place. If defenses are absent or misconfigured, this technique may be exploitable.

1. 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

M1045 Code Signing

Ensure all application component binaries are signed by the correct application developers.

M1047 Audit

Regularly check component software on critical services that adversaries may target for persistence to verify the integrity of the systems and identify if unexpected changes have been made.

M1024 Restrict Registry Permissions

Consider using Group Policy to configure and block modifications to service and other critical server parameters in the Registry.

M1042 Disable or Remove Feature or Program

Consider disabling software components from servers when possible to prevent abuse by adversaries.

M1046 Boot Integrity

Enabling secure boot allows validation of software and drivers during initial system boot.

M1018 User Account Management

Enforce the principle of least privilege by limiting privileges of user accounts so only authorized accounts can modify and/or add server software components.

M1026 Privileged Account Management

Do not allow administrator accounts that have permissions to add component software on these services to be used for day-to-day operations that may expose them to potential adversaries on unprivileged systems.

Detection

Detection Strategy for T1505 - Server Software Component

Risk Assessment

| Finding | Severity | Impact | | ---------------------------------------------- | -------- | ----------- | | Server Software Component technique applicable | Low | Persistence |

CWE Categories

| CWE ID | Title | | ------- | ----------------------------- | | CWE-276 | Incorrect Default Permissions |

References

• volexity_0day_sophos_FW
• US-CERT Alert TA15-314A Web Shells
• Atomic Red Team - T1505
• MITRE ATT&CK - T1505