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S3DNS is a powerful tool designed to help security professionals and threat actors discover exposed S3 buckets across AWS, GCP, and Azure while browsing. Acting as a DNS server, it follows CNAME records and matches bucket patterns, making it easier to identify misconfigured cloud storage.
Github Repository
Reddit Demo
You Should Know: How to Use S3DNS for Security Testing
Installation Steps
1. Clone the Repository:
git clone https://github.com/olizimmermann/s3dns.git cd s3dns
2. Install Dependencies:
pip install -r requirements.txt
3. Run S3DNS:
python s3dns.py --interface eth0
Key Commands & Usage
- Scan for Buckets:
python s3dns.py --target example.com
Enable Debug Mode:
python s3dns.py --debug
Save Output to File:
python s3dns.py --output buckets.txt
Verifying Bucket Permissions
Once a bucket is found, check its permissions using AWS CLI:
aws s3 ls s3://bucket-name --no-sign-request
If the bucket is misconfigured, you may be able to list or download files:
aws s3 cp s3://bucket-name/file.txt .
Automating with Bash
for bucket in $(cat buckets.txt); do aws s3 ls "s3://$bucket" --no-sign-request || echo "Bucket $bucket is secure" done
What Undercode Say
S3DNS is a critical tool for identifying exposed cloud storage, often leading to data breaches if buckets are misconfigured. Security teams should:
– Regularly audit S3/GCP/Azure buckets
– Enforce least-privilege access policies
– Monitor DNS logs for suspicious CNAME resolutions
Related Linux & Cloud Commands
- Check Open DNS Resolvers:
nmap -sU -p 53 --script dns-recursion <target>
Enumerate S3 Buckets via CLI:
curl -s http://s3.amazonaws.com/[bucket-name]/
Scan for Publicly Accessible Buckets:
s3scanner scan --bucket-list buckets.txt
AWS S3 Security Check:
aws s3api get-bucket-acl --bucket [bucket-name]
GCP Storage Check:
gsutil iam get gs://bucket-name
Expected Output:
A detailed report of discovered buckets, permissions, and potential exposures. Always use this tool ethically and report findings to the respective organizations.
🔗 Further Reading:
References:
Reported By: Abhirup Konwar – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅
