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https://github.com/ankane/s3tk
A security toolkit for Amazon S3
https://github.com/ankane/s3tk
Last synced: 13 days ago
JSON representation
A security toolkit for Amazon S3
- Host: GitHub
- URL: https://github.com/ankane/s3tk
- Owner: ankane
- License: mit
- Created: 2017-09-13T06:28:11.000Z (about 7 years ago)
- Default Branch: master
- Last Pushed: 2024-10-02T07:20:55.000Z (about 1 month ago)
- Last Synced: 2024-10-04T10:11:10.370Z (about 1 month ago)
- Language: Python
- Homepage:
- Size: 106 KB
- Stars: 451
- Watchers: 13
- Forks: 25
- Open Issues: 1
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- License: LICENSE.txt
Awesome Lists containing this project
- awesome - ankane/s3tk - A security toolkit for Amazon S3 (others)
- awesome-bugbounty-tools - s3tk - A security toolkit for Amazon S3 (Miscellaneous / Buckets)
- awesome-hacking-lists - ankane/s3tk - A security toolkit for Amazon S3 (Python)
README
# s3tk
A security toolkit for Amazon S3
> Another day, another leaky Amazon S3 bucket
>
> — The Register, 12 Jul 2017
Don’t be [the](https://www.theregister.co.uk/2017/07/12/14m_verizon_customers_details_out/)... [next](https://www.theregister.co.uk/2017/08/17/chicago_voter_leak/)... [big](https://www.theregister.co.uk/2017/09/05/twc_loses_4m_customer_records/)... [data](https://www.theregister.co.uk/2017/07/18/dow_jones_index_of_customers_not_prices_leaks_from_aws_repo/)... [leak](https://www.theregister.co.uk/2017/08/22/open_aws_s3_bucket_leaked_hotel_booking_service_data_says_kromtech/)
:tangerine: Battle-tested at [Instacart](https://www.instacart.com/opensource)
## Installation
Run:
```sh
pip install s3tk
```
You can use the [AWS CLI](https://github.com/aws/aws-cli) or [AWS Vault](https://github.com/99designs/aws-vault) to set up your AWS credentials:
```sh
pip install awscli
aws configure
```
See [IAM policies](#iam-policies) needed for each command.
## Commands
### Scan
Scan your buckets for:
- ACL open to public
- policy open to public
- public access blocked
- logging enabled
- versioning enabled
- default encryption enabled
```sh
s3tk scan
```
Only run on specific buckets
```sh
s3tk scan my-bucket my-bucket-2
```
Also works with wildcards
```sh
s3tk scan "my-bucket*"
```
Confirm correct log bucket(s) and prefix
```
s3tk scan --log-bucket my-s3-logs --log-bucket other-region-logs --log-prefix "{bucket}/"
```
Check CloudTrail object-level logging [experimental]
```sh
s3tk scan --object-level-logging
```
Skip logging, versioning, or default encryption
```sh
s3tk scan --skip-logging --skip-versioning --skip-default-encryption
```
Get email notifications of failures (via SNS)
```sh
s3tk scan --sns-topic arn:aws:sns:...
```
### List Policy
List bucket policies
```sh
s3tk list-policy
```
Only run on specific buckets
```sh
s3tk list-policy my-bucket my-bucket-2
```
Show named statements
```sh
s3tk list-policy --named
```
### Set Policy
**Note:** This replaces the previous policy
Only private uploads
```sh
s3tk set-policy my-bucket --no-object-acl
```
### Delete Policy
Delete policy
```sh
s3tk delete-policy my-bucket
```
### Block Public Access
Block public access on specific buckets
```sh
s3tk block-public-access my-bucket my-bucket-2
```
Use the `--dry-run` flag to test
### Enable Logging
Enable logging on all buckets
```sh
s3tk enable-logging --log-bucket my-s3-logs
```
Only on specific buckets
```sh
s3tk enable-logging my-bucket my-bucket-2 --log-bucket my-s3-logs
```
Set log prefix (`{bucket}/` by default)
```sh
s3tk enable-logging --log-bucket my-s3-logs --log-prefix "logs/{bucket}/"
```
Use the `--dry-run` flag to test
A few notes about logging:
- buckets with logging already enabled are not updated at all
- the log bucket must in the same region as the source bucket - run this command multiple times for different regions
- it can take over an hour for logs to show up
### Enable Versioning
Enable versioning on all buckets
```sh
s3tk enable-versioning
```
Only on specific buckets
```sh
s3tk enable-versioning my-bucket my-bucket-2
```
Use the `--dry-run` flag to test
### Enable Default Encryption
Enable [default encryption](https://docs.aws.amazon.com/AmazonS3/latest/dev/bucket-encryption.html) on all buckets
```sh
s3tk enable-default-encryption
```
Only on specific buckets
```sh
s3tk enable-default-encryption my-bucket my-bucket-2
```
This does not encrypt existing objects - use the `encrypt` command for this
Use the `--dry-run` flag to test
### Scan Object ACL
Scan ACL on all objects in a bucket
```sh
s3tk scan-object-acl my-bucket
```
Only certain objects
```sh
s3tk scan-object-acl my-bucket --only "*.pdf"
```
Except certain objects
```sh
s3tk scan-object-acl my-bucket --except "*.jpg"
```
### Reset Object ACL
Reset ACL on all objects in a bucket
```sh
s3tk reset-object-acl my-bucket
```
This makes all objects private. See [bucket policies](#bucket-policies) for how to enforce going forward.
Use the `--dry-run` flag to test
Specify certain objects the same way as [scan-object-acl](#scan-object-acl)
### Encrypt
Encrypt all objects in a bucket with [server-side encryption](https://docs.aws.amazon.com/AmazonS3/latest/dev/serv-side-encryption.html)
```sh
s3tk encrypt my-bucket
```
Use [S3-managed keys](https://docs.aws.amazon.com/AmazonS3/latest/dev/UsingServerSideEncryption.html) by default. For [KMS-managed keys](https://docs.aws.amazon.com/AmazonS3/latest/dev/UsingKMSEncryption.html), use:
```sh
s3tk encrypt my-bucket --kms-key-id arn:aws:kms:...
```
For [customer-provided keys](https://docs.aws.amazon.com/AmazonS3/latest/dev/ServerSideEncryptionCustomerKeys.html), use:
```sh
s3tk encrypt my-bucket --customer-key secret-key
```
Use the `--dry-run` flag to test
Specify certain objects the same way as [scan-object-acl](#scan-object-acl)
**Note:** Objects will lose any custom ACL
### Delete Unencrypted Versions
Delete all unencrypted versions of objects in a bucket
```sh
s3tk delete-unencrypted-versions my-bucket
```
For safety, this will not delete any current versions of objects
Use the `--dry-run` flag to test
Specify certain objects the same way as [scan-object-acl](#scan-object-acl)
### Scan DNS
Scan Route 53 for buckets to make sure you own them
```sh
s3tk scan-dns
```
Otherwise, you may be susceptible to [subdomain takeover](https://hackerone.com/reports/207576)
## Credentials
Credentials can be specified in `~/.aws/credentials` or with environment variables. See [this guide](https://boto3.readthedocs.io/en/latest/guide/configuration.html) for an explanation of environment variables.
You can specify a profile to use with:
```sh
AWS_PROFILE=your-profile s3tk
```
## IAM Policies
Here are the permissions needed for each command. Only include statements you need.
```json
{
"Version": "2012-10-17",
"Statement": [
{
"Sid": "Scan",
"Effect": "Allow",
"Action": [
"s3:ListAllMyBuckets",
"s3:GetBucketAcl",
"s3:GetBucketPolicy",
"s3:GetBucketPublicAccessBlock",
"s3:GetBucketLogging",
"s3:GetBucketVersioning",
"s3:GetEncryptionConfiguration"
],
"Resource": "*"
},
{
"Sid": "ScanObjectLevelLogging",
"Effect": "Allow",
"Action": [
"cloudtrail:ListTrails",
"cloudtrail:GetTrail",
"cloudtrail:GetEventSelectors",
"s3:GetBucketLocation"
],
"Resource": "*"
},
{
"Sid": "ScanDNS",
"Effect": "Allow",
"Action": [
"s3:ListAllMyBuckets",
"route53:ListHostedZones",
"route53:ListResourceRecordSets"
],
"Resource": "*"
},
{
"Sid": "ListPolicy",
"Effect": "Allow",
"Action": [
"s3:ListAllMyBuckets",
"s3:GetBucketPolicy"
],
"Resource": "*"
},
{
"Sid": "SetPolicy",
"Effect": "Allow",
"Action": [
"s3:PutBucketPolicy"
],
"Resource": "*"
},
{
"Sid": "DeletePolicy",
"Effect": "Allow",
"Action": [
"s3:DeleteBucketPolicy"
],
"Resource": "*"
},
{
"Sid": "BlockPublicAccess",
"Effect": "Allow",
"Action": [
"s3:ListAllMyBuckets",
"s3:PutBucketPublicAccessBlock"
],
"Resource": "*"
},
{
"Sid": "EnableLogging",
"Effect": "Allow",
"Action": [
"s3:ListAllMyBuckets",
"s3:PutBucketLogging"
],
"Resource": "*"
},
{
"Sid": "EnableVersioning",
"Effect": "Allow",
"Action": [
"s3:ListAllMyBuckets",
"s3:PutBucketVersioning"
],
"Resource": "*"
},
{
"Sid": "EnableDefaultEncryption",
"Effect": "Allow",
"Action": [
"s3:ListAllMyBuckets",
"s3:PutEncryptionConfiguration"
],
"Resource": "*"
},
{
"Sid": "ResetObjectAcl",
"Effect": "Allow",
"Action": [
"s3:ListBucket",
"s3:GetObjectAcl",
"s3:PutObjectAcl"
],
"Resource": [
"arn:aws:s3:::my-bucket",
"arn:aws:s3:::my-bucket/*"
]
},
{
"Sid": "Encrypt",
"Effect": "Allow",
"Action": [
"s3:ListBucket",
"s3:GetObject",
"s3:PutObject"
],
"Resource": [
"arn:aws:s3:::my-bucket",
"arn:aws:s3:::my-bucket/*"
]
},
{
"Sid": "DeleteUnencryptedVersions",
"Effect": "Allow",
"Action": [
"s3:ListBucketVersions",
"s3:GetObjectVersion",
"s3:DeleteObjectVersion"
],
"Resource": [
"arn:aws:s3:::my-bucket",
"arn:aws:s3:::my-bucket/*"
]
}
]
}
```
## Access Logs
[Amazon Athena](https://aws.amazon.com/athena/) is great for querying S3 logs. Create a table (thanks to [this post](http://aws.mannem.me/?p=1462) for the table structure) with:
```sql
CREATE EXTERNAL TABLE my_bucket (
bucket_owner string,
bucket string,
time string,
remote_ip string,
requester string,
request_id string,
operation string,
key string,
request_verb string,
request_url string,
request_proto string,
status_code string,
error_code string,
bytes_sent string,
object_size string,
total_time string,
turn_around_time string,
referrer string,
user_agent string,
version_id string
)
ROW FORMAT SERDE 'org.apache.hadoop.hive.serde2.RegexSerDe'
WITH SERDEPROPERTIES (
'serialization.format' = '1',
'input.regex' = '([^ ]*) ([^ ]*) \\[(.*?)\\] ([^ ]*) ([^ ]*) ([^ ]*) ([^ ]*) ([^ ]*) \\\"([^ ]*) ([^ ]*) (- |[^ ]*)\\\" (-|[0-9]*) ([^ ]*) ([^ ]*) ([^ ]*) ([^ ]*) ([^ ]*) ([^ ]*) (\"[^\"]*\\") ([^ ]*)$'
) LOCATION 's3://my-s3-logs/my-bucket/';
```
Change the last line to point to your log bucket (and prefix) and query away
```sql
SELECT
date_parse(time, '%d/%b/%Y:%H:%i:%S +0000') AS time,
request_url,
remote_ip,
user_agent
FROM
my_bucket
WHERE
requester = '-'
AND status_code LIKE '2%'
AND request_url LIKE '/some-keys%'
ORDER BY 1
```
## CloudTrail Logs
Amazon Athena is also great for querying CloudTrail logs. Create a table (thanks to [this post](https://www.1strategy.com/blog/2017/07/25/auditing-aws-activity-with-cloudtrail-and-athena/) for the table structure) with:
```sql
CREATE EXTERNAL TABLE cloudtrail_logs (
eventversion STRING,
userIdentity STRUCT<
type:STRING,
principalid:STRING,
arn:STRING,
accountid:STRING,
invokedby:STRING,
accesskeyid:STRING,
userName:String,
sessioncontext:STRUCT<
attributes:STRUCT<
mfaauthenticated:STRING,
creationdate:STRING>,
sessionIssuer:STRUCT<
type:STRING,
principalId:STRING,
arn:STRING,
accountId:STRING,
userName:STRING>>>,
eventTime STRING,
eventSource STRING,
eventName STRING,
awsRegion STRING,
sourceIpAddress STRING,
userAgent STRING,
errorCode STRING,
errorMessage STRING,
requestId STRING,
eventId STRING,
resources ARRAY>,
eventType STRING,
apiVersion STRING,
readOnly BOOLEAN,
recipientAccountId STRING,
sharedEventID STRING,
vpcEndpointId STRING,
requestParameters STRING,
responseElements STRING,
additionalEventData STRING,
serviceEventDetails STRING
)
ROW FORMAT SERDE 'com.amazon.emr.hive.serde.CloudTrailSerde'
STORED AS INPUTFORMAT 'com.amazon.emr.cloudtrail.CloudTrailInputFormat'
OUTPUTFORMAT 'org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat'
LOCATION 's3://my-cloudtrail-logs/'
```
Change the last line to point to your CloudTrail log bucket and query away
```sql
SELECT
eventTime,
eventName,
userIdentity.userName,
requestParameters
FROM
cloudtrail_logs
WHERE
eventName LIKE '%Bucket%'
ORDER BY 1
```
## Best Practices
Keep things simple and follow the principle of least privilege to reduce the chance of mistakes.
- Strictly limit who can perform bucket-related operations
- Avoid mixing objects with different permissions in the same bucket (use a bucket policy to enforce this)
- Don’t specify public read permissions on a bucket level (no `GetObject` in bucket policy)
- Monitor configuration frequently for changes
## Bucket Policies
Only private uploads
```json
{
"Version": "2012-10-17",
"Statement": [
{
"Effect": "Deny",
"Principal": "*",
"Action": "s3:PutObjectAcl",
"Resource": "arn:aws:s3:::my-bucket/*"
}
]
}
```
## Performance
For commands that iterate over bucket objects (`scan-object-acl`, `reset-object-acl`, `encrypt`, and `delete-unencrypted-versions`), run s3tk on an EC2 server for minimum latency.
## Notes
The `set-policy`, `block-public-access`, `enable-logging`, `enable-versioning`, and `enable-default-encryption` commands are provided for convenience. We recommend [Terraform](https://www.terraform.io/) for managing your buckets.
```tf
resource "aws_s3_bucket" "my_bucket" {
bucket = "my-bucket"
acl = "private"
logging {
target_bucket = "my-s3-logs"
target_prefix = "my-bucket/"
}
versioning {
enabled = true
}
}
resource "aws_s3_bucket_public_access_block" "my_bucket" {
bucket = "${aws_s3_bucket.my_bucket.id}"
block_public_acls = true
block_public_policy = true
ignore_public_acls = true
restrict_public_buckets = true
}
```
## Upgrading
Run:
```sh
pip install s3tk --upgrade
```
To use master, run:
```sh
pip install git+https://github.com/ankane/s3tk.git --upgrade
```
## Docker
Run:
```sh
docker run -it ankane/s3tk aws configure
```
Commit your credentials:
```sh
docker commit $(docker ps -l -q) my-s3tk
```
And run:
```sh
docker run -it my-s3tk s3tk scan
```
## History
View the [changelog](https://github.com/ankane/s3tk/blob/master/CHANGELOG.md)
## Contributing
Everyone is encouraged to help improve this project. Here are a few ways you can help:
- [Report bugs](https://github.com/ankane/s3tk/issues)
- Fix bugs and [submit pull requests](https://github.com/ankane/s3tk/pulls)
- Write, clarify, or fix documentation
- Suggest or add new features
To get started with development:
```sh
git clone https://github.com/ankane/s3tk.git
cd s3tk
pip install -r requirements.txt
```