{
  "id": 5918418,
  "title": "Exposed Buckets: How S3, GCS, and Azure Blob Are Passively Discovered and Exploited",
  "url": "https://urgent.news/2026/09/06/exposed-buckets-how-s3-gcs-and-azure-blob-are-passively-discovered",
  "topic": "tech",
  "section": "Tech",
  "published": "2026-09-06T05:45:53.000Z",
  "source": {
    "name": "Dev.to",
    "slug": "dev-to",
    "url": "https://dev.to/roxdavirox/exposed-buckets-how-s3-gcs-and-azure-blob-are-passively-discovered-and-exploited-5d6c"
  },
  "original_language": "en",
  "account": "Cloud storage buckets from major providers, such as Amazon S3, Google Cloud Storage, and Azure Blob, can be passively discovered and exploited without triggering any security alerts. This issue stems from the fact that attackers can use publicly available certificate transparency (CT) logs to identify naming patterns and generate bucket name permutations. Once identified, tools like GrayhatWarfare and snallybuckster can confirm whether sensitive files, such as .env, .sql, .key, .pem, and .bak files, have been indexed.\n\nTo confirm the existence of these files, attackers can use specialized scanners like S3Scanner, AWSBucketDump, and GCSBucketBrute. These scanners perform permission checks and crawl bucket contents without triggering any security events, as they do not require authentication. The active phase of the attack is brief, involving a simple permission scan against a list of identified bucket names.\n\nThe most significant aspect of this attack is that the initial discovery phase happens passively and leaves no traceable evidence. This asymmetry between the passive discovery phase and the subsequent active scanning phase is often overlooked, leading to undetected security breaches. For instance, in 2017, Accenture had four public S3 buckets containing sensitive information, including API keys, VPN keys, and Top Secret classified documents. The breach was discovered and fixed within 24 hours of being reported. Booz Allen Hamilton also experienced a major breach, with 60,000 files containing Top Secret information, which was discovered by Chris Vickery and left unaddressed for several days. Time Warner suffered a breach involving four million customer records, while other companies like Booz Allen, GoDaddy, and Time Warner had similar incidents.\n\nTo mitigate these risks, companies should focus on implementing proper cloud security policies and monitoring tools to detect potential exposure early. Additionally, regular audits of indexed files in services like GrayhatWarfare can help identify and remediate potential security vulnerabilities before they are exploited.",
  "summary": "Before running a single scanner, a researcher opens bucket-stream, connects to certstream, and within minutes has a list of S3 buckets derived from the target company's subdomains. No packet was sent to the target. No log was written to the SIEM. Most security teams treat bucket exposure as a configuration problem fixed with a click on \"Block Public Access\". That assumption misses the point: even…",
  "key_points": [
    "Attackers use CT logs to identify naming patterns and generate bucket names.",
    "Specialized scanners confirm existence of sensitive files without triggering alerts.",
    "Passive discovery phase leaves no traceable evidence, leading to undetected breaches."
  ],
  "editors_take": "This passive discovery method shifts the burden to cloud storage users to proactively secure their buckets, as attackers can exploit publicly available logs and tools to identify and access sensitive files without detection.",
  "illustration": null,
  "coverage": {
    "outlets": 1,
    "also_reported_by": []
  },
  "ai_generated": true,
  "disclaimer": "Summaries, key points and the editor’s take are written by software from other outlets’ reporting and may contain errors — always check the linked original."
}