Description

Kubernetes default configuration is overly permissive, allowing users to escalate privileges or execute commands as privileged users.

Impact

Gain total control over one or more PoDs.

Recommendation

Set strict security policy disabling potentially harmful actions and restricting the user permissions.

Threat

Authenticated attacker with local access to PoD or container.

Expected Remediation Time

⌚ 30 minutes.

Score

Default score using CVSS 3.1. It may change depending on the context of the src.

Base

• Attack vector: L
• Attack complexity: L
• Privileges required: L
• User interaction: N
• Scope: U
• Confidentiality: L
• Integrity: L
• Availability: L

Temporal

• Exploit code maturity: U
• Remediation level: O
• Report confidence: C

Result

• Vector string: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L/E:U/RL:O/RC:C
• Score:
• Base: 5.3
• Temporal: 4.6
• Severity:
• Base: Medium
• Temporal: Medium

Score 4.0

Default score using CVSS 4.0. It may change depending on the context of the src.

Base 4.0

• Attack vector: L
• Attack complexity: L
• Attack Requirements: N
• Privileges required: L
• User interaction: N
• Confidentiality (VC): L
• Integrity (VI): L
• Availability (VA): L
• Confidentiality (SC): N
• Integrity (SI): N
• Availability (SA): N

Threat 4.0

• Exploit maturity: U

Result 4.0

• Vector string: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:U
• Score:
• CVSS-BT: 1.1
• Severity:
• CVSS-BT: Low

Compliant code

The resource has enabled safe security policies by restricting privileges to authorized users

                apiVersion: v1
kind: Pod
metadata:
  name: rss-site
  labels:
    app: web
spec:
  privileged: false
  containers:
- name: front-end
      image: nginx
      ports:
- containerPort: 80
      securityContext:
        capabilities:
            add:
- SYS_ADMIN
- NET_ADMIN
- name: rss-reader
      image: nickchase/rss-php-nginxv1
      ports:
- containerPort: 88

            

                apiVersion: v1
kind: Pod
metadata:
  name: rss-site
  labels:
    app: web
spec:
  containers:
- name: front-end
      image: nginx
      ports:
- containerPort: 80
      securityContext:
        allowPrivilegeEscalation: false
        capabilities:
          drop:
- all
          add:
- NET_BIND_SERVICE
- name: rss-reader
      image: nickchase/rss-php-nginxv1
      ports:
- containerPort: 88

            

Non compliant code

The resource does not enable safe security policies allowing privileged execution

                apiVersion: v1
kind: Pod
metadata:
  name: rss-site
  labels:
    app: web
spec:
  privileged: true
  containers:
- name: front-end
      image: nginx
      ports:
- containerPort: 80
      securityContext:
        capabilities:
            add:
- SYS_ADMIN
- NET_ADMIN
- name: rss-reader
      image: nickchase/rss-php-nginxv1
      ports:
- containerPort: 88

            

                apiVersion: v1
kind: Pod
metadata:
  name: rss-site
  labels:
    app: web
spec:
  containers:
- name: front-end
      image: nginx
      ports:
- containerPort: 80
      securityContext:
        allowPrivilegeEscalation: true
        capabilities:
          drop:
- all
          add:
- NET_BIND_SERVICE
- name: rss-reader
      image: nickchase/rss-php-nginxv1
      ports:
- containerPort: 88

            

Details

https://kubernetes.io/docs/concepts/security/pod-security-standards/#restricted https://kubernetes.io/docs/tasks/configure-pod-container/security-context/

Requirements

• 095.Define users with privileges
• 096.Set user's required privileges
• 186.Use the principle of least privilege

Fixes

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