Skip to content

Latest commit

 

History

History
54 lines (45 loc) · 7.8 KB

attack-surface.md

File metadata and controls

54 lines (45 loc) · 7.8 KB

Attack Surface Analysis for containers/podman

Attack Surface: Exposed Podman API (TCP Socket)

  • Description: Podman API exposed over TCP without proper authentication and authorization, allowing unauthenticated remote access.
  • Podman Contribution: Podman's configuration allows enabling the API to listen on a TCP socket, facilitating remote management but also creating a potential remote attack vector if not secured.
  • Example: A system administrator configures Podman to listen on TCP port 2376 for remote access but fails to implement TLS and client authentication. This leaves the Podman API open to anyone who can reach the port on the network.
  • Impact: Unauthenticated remote attackers gain full control over the Podman instance. This includes the ability to create, start, stop, and delete containers; pull and manage images; and potentially gain code execution on the host system depending on user permissions and Podman configuration.
  • Risk Severity: Critical
  • Mitigation Strategies:
    • Avoid TCP Socket Exposure: If remote API access is not absolutely necessary, use the default Unix socket which is only accessible locally.
    • Mandatory TLS Encryption: If TCP socket exposure is required, enforce TLS encryption for all API communication to protect confidentiality and integrity.
    • Strong Client Authentication: Implement robust client authentication mechanisms such as client certificate authentication to restrict API access to authorized entities only.
    • Network Access Control: Use firewalls and network segmentation to limit network access to the Podman API port to trusted networks and authorized systems.

Attack Surface: Container Escape due to Kernel or Runtime Vulnerabilities (Rootful Mode)

  • Description: Exploiting vulnerabilities in the underlying Linux kernel or the container runtime (like runc or crun) to escape container isolation and gain unauthorized access to the host system when running Podman in rootful mode.
  • Podman Contribution: Podman relies on the kernel and the configured container runtime for container isolation. Vulnerabilities in these components directly undermine Podman's security model in rootful mode.
  • Example: A publicly disclosed vulnerability in runc (the default container runtime often used by Podman) allows an attacker within a rootful container to escape the container and execute arbitrary commands as root on the host operating system.
  • Impact: Complete compromise of the host system, including data breaches, system instability, and the ability for attackers to establish persistence and further attacks.
  • Risk Severity: Critical (in rootful mode)
  • Mitigation Strategies:
    • Prioritize Rootless Mode: Run containers in rootless mode whenever feasible. Rootless mode significantly reduces the impact of container escapes by limiting the attacker's privileges to the user context, even after a successful escape.
    • Keep Host OS and Podman Components Updated: Maintain a rigorous patching schedule for the host operating system kernel, Podman itself, and all its dependencies (including runc, crun, and other runtime components). Timely updates are crucial to address known vulnerabilities.
    • Enforce Security Contexts (SELinux/AppArmor): Utilize mandatory access control systems like SELinux or AppArmor to further restrict container capabilities and limit the potential damage from a container escape, even if it occurs.
    • Implement Seccomp Profiles: Employ seccomp profiles to restrict the syscalls available to containers, reducing the attack surface for kernel exploits and making container escapes more difficult.

Attack Surface: Host Networking Mode

  • Description: Running containers in host networking mode, which bypasses network isolation and directly exposes the host's network stack to the container, increasing the risk of host compromise from a compromised container.
  • Podman Contribution: Podman provides the host networking mode as a configuration option. While it can be useful in specific scenarios, it inherently weakens container isolation from a network security perspective.
  • Example: A container running in host networking mode hosts a vulnerable web application. An attacker exploiting this vulnerability gains direct access to the host's network interfaces and any services running on the host, bypassing container network isolation entirely.
  • Impact: Loss of network isolation for the container, direct access to host network services from within the container, significantly increased risk of host system compromise and lateral movement within the network.
  • Risk Severity: High to Critical (depending on the services running on the host and the container workload)
  • Mitigation Strategies:
    • Avoid Host Networking Mode: Restrict the use of host networking mode to only absolutely necessary situations. Carefully evaluate the security implications before using it.
    • Utilize Bridge or Overlay Networks: Prefer using bridge or overlay networks for container networking to maintain network isolation between containers and the host, and between containers themselves.
    • Network Segmentation and Firewalls: Implement network segmentation to isolate container networks from sensitive host networks. Use firewalls to further restrict network traffic to and from containers and the host.
    • Regular Security Audits of Network Configurations: Periodically review container network configurations to identify and remediate any instances of unnecessary host networking mode usage.

Attack Surface: Vulnerabilities in Podman Dependencies

  • Description: Security vulnerabilities present in the libraries and components that Podman relies upon, such as runc, crun, container networking libraries, and storage libraries. These vulnerabilities can directly impact Podman's security and potentially lead to container escapes or host compromise.
  • Podman Contribution: Podman's functionality is built upon and depends on these external libraries. Vulnerabilities in these dependencies directly translate to vulnerabilities in Podman itself.
  • Example: A critical vulnerability is discovered in the runc container runtime, a core dependency of Podman. If a Podman installation uses a vulnerable version of runc, all containers managed by that Podman instance become susceptible to container escape attacks exploiting this runc vulnerability.
  • Impact: Container escapes, host system compromise, denial of service, and other security breaches, depending on the nature and severity of the dependency vulnerability.
  • Risk Severity: High to Critical (depending on the severity of the dependency vulnerability)
  • Mitigation Strategies:
    • Maintain Up-to-Date Podman and Dependencies: Establish a robust process for regularly updating Podman and all its dependencies to the latest versions. This is the most critical mitigation step.
    • Automated Vulnerability Scanning: Implement automated vulnerability scanning tools to continuously monitor Podman and its dependencies for known vulnerabilities.
    • Dependency Management and Tracking: Maintain a clear inventory of Podman's dependencies and actively track security advisories and vulnerability disclosures related to these components.
    • Security Monitoring and Alerting: Set up security monitoring and alerting systems to promptly detect and respond to any reported vulnerabilities affecting Podman or its dependencies.