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s3scanner

v3.0.3 open-source

S3Scanner is a tool to find open S3 buckets in AWS or other cloud providers and scans all bucket permissions to find misconfigurations.

Summary

s3scanner is an open-source, MIT-licensed command-line tool that finds open or misconfigured S3-compatibleS3-compatibleAn object-storage API that mirrors Amazon S3's HTTP interface, so any client or cyber tool written for AWS S3 works unchanged against any compliant storage backend. storage buckets across AWS, GCP, DigitalOcean, DreamHost, Linode, Scaleway, and custom endpoints, checking permissions and enumerating objects rather than just confirming existence. It runs multi-threaded from the terminal or Docker, can save results to Postgres, and pulls bucket names from RabbitMQ for scanning at scale, which suits red teamers and bug bounty hunters doing recon over one-off checks. It's used as a component inside recon frameworks like reconFTW, reNgine, and axiom rather than run standalone by most of its users. First committed in 2017 with 13 contributors, it still saw 6 commits in the past year, though its last release was over 700 days ago.

S3Scanner is a tool to find open S3 buckets in AWS or other cloud providers and scans all bucket permissions to find misconfigurations.

How s3scanner helps

Which of my company's guessable S3 bucket names are actually exposed on the internet right now?

checks each name in a list against AWS and other providers and reports which ones exist and are reachable, rather than just guessing at DNS resolution

Which of the buckets I found can strangers actually read from or write to?

tests each discovered bucket against the full set of permission checks so you see which ones allow anonymous read, write, or ACL access instead of just confirming a bucket exists

What's actually sitting inside a bucket that turned out to be open?

walks the bucket and lists out its objects so you know what data would be exposed, not just that the bucket itself is reachable

Have I already found this exposure before, or is it new since my last scan?

writes each scan's results into Postgres, so past and current findings sit in one place you can diff or query instead of re-reading terminal output

Can my recon pipeline keep discovering and checking bucket names without me feeding them in by hand?

pulls bucket names off a RabbitMQ queue as other tools produce them, checking each one as it arrives so discovery and verification run as one continuous pass at scale

Which bucket names in a huge candidate list are worth a human's attention?

runs checks across many threads at once and can emit JSON, so the output can be piped straight into a filter that keeps only the buckets confirmed to exist

all 12 features, with the evidence for each →

Languages

Not documented

Features

12 capabilities · 2 backed by code, an API document or a real run

Built from s3scanner's releases, docs, README and our own runs. “Seen” marks the month we first spotted a release the vendor didn't date. Group names and tags are our labels.

Compare with peers →

  • s3scanner covers 1 of the 8 data discovery and protection capabilities we track.

What s3scanner offers you

  • Command-line interface5
  • JSON data export2
  • S3 export1
All capabilities 12 capabilities
Cloud provider support shipped Scans buckets across multiple cloud providers and S3-compatible infrastructures. 4 releases · 3 other sources · first seen Mar 2018

release

  • add scaleway support to scan S3-compatible buckets on the Scaleway infrastructure v3.0.3 · Sep 2023 · source · release history
  • Supports scanning non-AWS S3-compatible APIs via generic backend instead of AWS-only 2.0.0 · Apr 2021 · source · release history
  • Adds getAcl() function which attempts to retrieve Access Control Lists (ACLs) for discovered buckets. 1.0.0 · Mar 2018 · source · release history
  • checkBucket() now uses the boto library instead of HTTP GET requests to identify buckets, correctly finding private but listable buckets and eliminating the need for region specifications. 1.0.0 · Mar 2018 · source · release history

docs

  • Scans AWS and other cloud providers for open, misconfigured S3 buckets and enumerates their permissions and objects.

example

  • Scan a non-AWS S3-compatible endpoint (e.g., MinIO) for anonymous access s3scanner scan --endpoint-url https://minio.example.com -b test-bucket 2.0.0 · Apr 2021 · source
  • Scan GCP bucket, save results to DB s3scanner -provider gcp -db -bucket my-bucket -enumerate
Bucket enumeration scanning verified suggested Scans a supplied path or target for bucket enumeration results, reporting an invalid status when the input is not recognised. 2 releases · 2 other sources · first seen Mar 2018

Suggested capability: Sensitive data discovery. This is our guess, not confirmed.

Also counts toward: Command-line interface

release

  • Adds multi-threaded scanning and dumping to speed up bucket enumeration and object retrieval 2.0.0 · Apr 2021 · source · release history
  • Bucket input file format is now buckets.txt containing only bucket names, dropping the previous bucket:region format. 1.0.0 · Mar 2018 · source · release history

command line

  • -threads — int Number of threads to scan with. Default: "4" v3.0.0 · Jul 2023 · command-line history

we ran it

  • The tool reported the target as invalid, printing a single invalid status line for the supplied path. It exited 0 despite the invalid input, producing no bucket enumeration results. Aug 2026 · the full run
CLI configuration and verbosity controls verified Exposes command-line flags to set the number of scan threads, enable verbose logging, and print the tool version. 1 release · 2 other sources · first seen Mar 2018

Also counts toward: Command-line interface

release

  • Adds new CLI flag --version to display the tool's version number. 1.0.0 · Mar 2018 · source · release history

command line

Configuration management shipped Manages timeouts and configuration validation, such as detecting missing AWS credentials. 3 releases · first seen Mar 2018

release

  • Adds automated tests to validate 3rd party endpoints 2.0.1 · Apr 2021 · source · release history
  • Adds a warning when properly configured AWS credentials are not found 0.2.0 · Mar 2018 · source · release history
  • Adds the sizeCheckTimeout variable for configuring the timeout duration of getSize() calls 0.1.1 · Mar 2018 · source · release history
Scanning scope control shipped Supports scanning single buckets, enumerating all objects within a bucket, or processing lists of buckets. 3 other sources

example

  • Scan a single bucket s3scanner -bucket secret_uploads
  • Enumerate all objects in a bucket s3scanner -bucket attachments -enumerate
  • Scan bucket list, enumerate all objects s3scanner -bucket-file names.txt -enumerate
Proxy routing support shipped Routes scanning requests through a custom HTTP proxy. 1 release · 1 other source · first seen Sep 2023

Also counts toward: Command-line interface

release

  • Adds proxy support via --proxy CLI flag to route S3 requests through a custom HTTP proxy v3.0.2 · Sep 2023 · source · release history

example

  • Scan buckets through a corporate HTTP proxy that requires external routing. s3scanner --proxy http://10.0.0.1:8080 my-bucket-name v3.0.2 · Sep 2023 · source
Output and result filtering shipped Exports scan results in JSON format and supports filtering existing buckets. 1 release · 1 other source · first seen Apr 2021

Also counts toward: Command-line interface, JSON data export

release

  • Output is now unified to stdout; previous separate file and console format flags are removed 2.0.0 · Apr 2021 · source · release history

example

  • Output JSON, filter existing buckets with jq s3scanner -bucket-file names.txt -json | jq -r '. | select(.bucket.exists==1) | [.bucket.name, .bucket.region] | join(" - ")'
Data export capabilities shipped Exports scan results or bucket listings to files for offline analysis. 1 release · 1 other source · first seen Mar 2018

Also counts toward: Command-line interface, JSON data export, S3 export

release

  • Adds --list argument to enable saving bucket listings to file 0.2.0 · Mar 2018 · source · release history

example

  • Save the full contents of a public S3 bucket to a JSON file for later analysis. s3scanner --list -b my-public-bucket 0.2.0 · Mar 2018 · source
Region validation shipped Validates bucket regions during the scanning process. 1 release · first seen Sep 2023

release

Incremental object dumping shipped Supports resuming dumps by skipping already-downloaded objects unless their sizes differ. 1 release · first seen Apr 2021

release

  • Adds resume-able dumping that skips already-downloaded objects unless sizes differ 2.0.0 · Apr 2021 · source · release history
Permission auditing shipped Checks for dangerous permissions such as Write and WriteACP during bucket enumeration. 1 release · first seen Apr 2021

Shared capability: Data access governance

release

  • Adds checks for dangerous permissions (Write, WriteACP) during bucket enumeration 2.0.0 · Apr 2021 · source · release history
Data source integration shipped Ingests bucket names from external queues for scanning. 1 other source

example

  • Consume bucket names from RabbitMQ s3scanner -mq

Lines in monospace are the tool's own words: help text parsed from its source, or an endpoint from its API document. Under release, a line is our summary of a dated release. Under docs, it is quoted from the tool's own documentation or website. Each links back to the source it came from.

Score card

  1. Shipping velocity releases a month, last 12 months
  2. Documentation quality release-notes rubric, 0–100
  3. Breaking-change discipline how rarely a release breaks users, and notice given
  4. Maintenance risk quiet time against its own cadence, maintainers
  5. Innovation & surface new capabilities, API and MCP surface
  6. Community health
  7. Contributor trend distinct committers, this year against last
  8. Maintainer concentration bus factor now against a year ago
  9. Issue backlog trend issues closed per issue opened, 12 months
  10. Responsiveness median time to a maintainer’s first reply

Nine scores for s3scanner, each built from the releases, notes and API history this site tracks — and, on Researcher and Business, where it stands among every measured tool in its category and how that has moved.

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Each score is 0–100 on a published rubric, derived from data this site already shows. A dimension we cannot measure says so — it is never scored 0 and never enters a rank.

How this is scored
  • Shipping velocity — releases a month over the last 12 months, on a log scale where 16 a month scores 100. Needs 3 releases in the window.
  • Documentation quality — the release-notes rubric published on the analytics page, unchanged.
  • Breaking-change discipline — the share of releases carrying a breaking change (none scores 100, half or more scores 0). Only projects that label breaking changes are measured: a clean record cannot be told from an unlabelled one.
  • Maintenance risk — quiet time measured against the tool's own release cadence (quiet longer than 90 days and three typical gaps scores 0), plus the number of active maintainers and whether contributors are growing, where known. Higher is lower risk.
  • Innovation & surface — new capabilities in the feature ledger this year, API and MCP operations added, and the share of commits that are features: the mean of whichever we hold.
  • Community health (open-source tools only) — each is a direction, not a size: contributors this year against last, the bus factor now against a year ago, and issues closed per issue opened, where steady scores 50, doubled 100 and halved 0; plus the median time to a maintainer's first reply (an hour scores about 100, a month or more 0). A commercial card has no repository and carries none of the four.
  • Documented delivery (commercial tools) — when a vendor's documented new capabilities have slowed against its own baseline, that counts against the overall standing as heavily as two low dimensions. Steady delivery, or too little history to judge, leaves the standing alone; it is never a sixth score.
  • Open-source tools are scored on repository signals; commercial tools on their published changelog. Ranks compare tools within one category and one profile and need at least five measured peers; the overall standing needs three ranked dimensions. Best-in-breed or consolidator is a shape, not a quality, and is never scored.

Release-note detail over time

See how much detail s3scanner puts in its release notes, quarter by quarter, and compare it with tracked tools in the same category. This history uses up to ten retained, reviewed notes per tool; sparse or blank older quarters may reflect that limit.

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Releases

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7 entries

  1. September 20232
  2. April 20212
  3. March 20183
    Show

    7 entries

    Project health

    Issue, contributor and maintainer activity in sa7mon/s3scanner, 2023-10 – 2026-09, as of 2026-09-25. Twelve-month figures first; the trend lines run the whole window.

    1. Contributors 1 ±0 vs prior 12 months
    2. Maintainers 1 +0 joined · −0 left, last 12 months
    3. Bus factor 1 committers behind half the commits
    4. Community-filed 33% of issues opened, last 12 months
    5. Median time to close < 1 day first maintainer reply 0.7 hours
    6. Open backlog 36 of 149 issues ever filed
    1. Issues opened / month 0 · 0 communitymaintainers
    2. Open backlog 36
    3. Contributors / month 0
    4. Commits / month 0
    5. Stars 3,172
    Issue themes, last 12 months
    • bugs 67%
    • other 33%

    Counts from the project's public repository and git history; no individuals are identified. Maintainers are the committers covering 80% of the last year's commits. how we measure this

    Libraries its release ships

    What its latest release locks, checked against known advisories.

    None of its release's images build from a lockfile we can read.

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