Reverse Shell

This document describes a threat finding type in Security Command Center. Threat findings are generated by threat detectors when they detect a potential threat in your cloud resources. For a full list of available threat findings, see Threat findings index.

Overview

A process started with stream redirection to a remote connected socket. Spawning a network-connected shell can allow an attacker to perform arbitrary actions after a limited initial compromise.

Cloud Run Threat Detection is the source of this finding.

How to respond

To respond to this finding, do the following:

Review finding details

  1. Open the Reverse Shell finding as directed in Reviewing findings. Review the details on the Summary and JSON tabs.

  2. On the Summary tab, review the information in the following sections:

    • What was detected, especially the following fields:
      • Program binary: the absolute path of the process started with stream redirection to a remote socket
      • Arguments: the arguments provided when the process binary was invoked
    • Affected resource, especially the following fields:
      • Resource full name: the full resource name of the affected Cloud Run resource
      • Project full name: the affected Google Cloud project
    • Related links, especially the following fields:
      • VirusTotal indicator: link to the VirusTotal analysis page

  3. On the JSON tab, note the following fields:

    • resource:
      • project_display_name: the name of the project that contains the asset.
    • sourceProperties:
      • Reverse_Shell_Stdin_Redirection_Dst_Ip: the remote IP address of the connection
      • Reverse_Shell_Stdin_Redirection_Dst_Port: the remote port
      • Reverse_Shell_Stdin_Redirection_Src_Ip: the local IP address of the connection
      • Reverse_Shell_Stdin_Redirection_Src_Port: the local port
      • Container_Image_Uri: the name of the container image being executed.

  4. Look for related findings that occurred at a similar time for the affected container. Such findings might indicate that this activity was malicious, instead of a failure to follow best practices.

  5. Review the settings of the affected container.

  6. Check the logs for the affected container.

Research attack and response methods

  1. Review the MITRE ATT&CK framework entries for this finding type: Command and Scripting Interpreter and Ingress Tool Transfer.
  2. Check the SHA-256 hash value for the binary flagged as malicious on VirusTotal by clicking the link in VirusTotal indicator. VirusTotal is an Alphabet-owned service that provides context on potentially malicious files, URLs, domains, and IP addresses.
  3. To develop a response plan, combine your investigation results with the MITRE research and VirusTotal analysis.

Implement your response

For response recommendations, see Respond to Cloud Run threat findings.

What's next