T1505: Server Software Component

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.

Positive Technologies products that cover the technique

MaxPatrol SIEM knowledge base

supply_chain: PT-CR-1934: SupplyChain_TeamCity_Plugin_Modify: A plugin was used. Attackers can manipulate TeamCity plugins to upload malicious code pt_application_firewall: PT-CR-1916: PTAF_Webshell_Detected: PT AF detected an attempt to upload a web shell to a web server mitre_attck_execution: PT-CR-651: Suspicious_Webscript: A user attempted to start an unknown script unix_mitre_attck_persistence: PT-CR-1027: Unix_Webshell_Created: A possible attempt to upload a web shell on a Unix web server mitre_attck_persistence: PT-CR-266: Windows_Webshell_Created: A potential attempt to deploy a web shell on a Windows web server is detected

Subtechniques

Expert Required. The technique is detected only with the combination of «PT Product + Expert»

Detection

IDDS0015Data source and componentApplication Log: Application Log ContentDescription

Monitor for third-party application logging, messaging, and/or other artifacts that may abuse legitimate extensible development features of servers to establish persistent access to systems. Consider monitoring application logs for abnormal behavior that may indicate suspicious installation of application software components. Log authentication attempts to the server and any unusual traffic patterns to or from the server and internal network.

IDDS0029Data source and componentNetwork Traffic: Network Traffic FlowDescription

Monitor network data for uncommon data flows. Processes utilizing the network that do not normally have network communication or have never been seen before are suspicious.

IDDS0022Data source and componentFile: File ModificationDescription

Monitor for changes made to files that may abuse legitimate extensible development features of servers to establish persistent access to systems.

IDDS0022Data source and componentFile: File CreationDescription

Consider monitoring file locations associated with the installation of new application software components such as paths from which applications typically load such extensible components.

IDDS0009Data source and componentProcess: Process CreationDescription

Process monitoring may be used to detect servers components that perform suspicious actions such as running cmd.exe or accessing files.

IDDS0029Data source and componentNetwork Traffic: Network Traffic ContentDescription

Monitor and analyze traffic patterns and packet inspection associated to protocol(s), leveraging SSL/TLS inspection for encrypted traffic, that do not follow the expected protocol standards and traffic flows (e.g extraneous packets that do not belong to established flows, gratuitous or anomalous traffic patterns, anomalous syntax, or structure). Consider correlation with process monitoring and command line to detect anomalous processes execution and command line arguments associated to traffic patterns (e.g. monitor anomalies in use of files that do not normally initiate connections for respective protocol(s)).

Mitigation

IDM1018NameUser Account ManagementDescription

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

IDM1024NameRestrict Registry PermissionsDescription

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

IDM1026NamePrivileged Account ManagementDescription

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.

IDM1042NameDisable or Remove Feature or ProgramDescription

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

IDM1045NameCode SigningDescription

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

IDM1047NameAuditDescription

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.