{"description":"Trending threats, MITRE ATT\u0026CK coverage, and detection metadata. Fed continuously.","feed_url":"https://feed.craftedsignal.io/products/aws-cloudfront/feed.json","home_page_url":"https://feed.craftedsignal.io/","items":[{"_cs_actors":[],"_cs_cpes":[],"_cs_cves":[],"_cs_exploited":false,"_cs_has_poc":false,"_cs_poc_references":[],"_cs_products":["AWS S3","AWS IAM","AWS CloudTrail","AWS CloudFront"],"_cs_severities":["medium"],"_cs_tags":["aws","s3","static-website","javascript","web-defacement"],"_cs_type":"advisory","_cs_vendors":["Amazon"],"content_html":"\u003cp\u003eThis threat brief focuses on the detection of unauthorized modifications to static websites hosted on Amazon S3. Specifically, it addresses the risk of malicious actors uploading JavaScript files to directories commonly used for static site assets (e.g., \u003ccode\u003estatic/js/\u003c/code\u003e). This activity can be indicative of a compromised IAM user or role being leveraged to inject malicious scripts into the website's frontend, potentially leading to defacement, data theft, or redirection of users to phishing sites. The focus is on identifying deviations from expected behavior, such as uploads originating from outside of established CI/CD pipelines or performed by unauthorized IAM entities. The rule described was last updated on 2026-04-10, and targets AWS CloudTrail logs. The detection is designed to exclude common automation tools like Terraform, Ansible, and Pulumi to reduce false positives.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAn attacker gains unauthorized access to an AWS account, potentially through compromised IAM credentials or a misconfigured IAM role.\u003c/li\u003e\n\u003cli\u003eThe attacker enumerates available S3 buckets to identify those hosting static websites, likely using \u003ccode\u003eListBuckets\u003c/code\u003e or similar API calls.\u003c/li\u003e\n\u003cli\u003eThe attacker identifies the target bucket and the directory containing JavaScript files (e.g., \u003ccode\u003estatic/js/\u003c/code\u003e).\u003c/li\u003e\n\u003cli\u003eThe attacker crafts a malicious JavaScript file designed to inject malicious code into the website.\u003c/li\u003e\n\u003cli\u003eThe attacker uploads the malicious JavaScript file to the identified S3 bucket and directory using the \u003ccode\u003ePutObject\u003c/code\u003e API call.\u003c/li\u003e\n\u003cli\u003eIf CloudFront is used, the attacker may invalidate the CloudFront cache to ensure the malicious JavaScript file is immediately served to users.\u003c/li\u003e\n\u003cli\u003eWebsite visitors unknowingly execute the malicious JavaScript code, leading to client-side attacks such as data theft or redirection to phishing sites.\u003c/li\u003e\n\u003cli\u003eThe attacker achieves the objective of defacing the website, stealing user data, or spreading malware.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eA successful attack can lead to defacement of the website, reputational damage, and potential loss of user data. The compromise of the website's frontend can allow attackers to inject malicious scripts that steal user credentials, redirect users to phishing sites, or spread malware. The number of affected users depends on the website's traffic. This type of attack is particularly concerning for e-commerce websites, financial institutions, and other organizations that handle sensitive user data. Mitigation requires swift action to remove the malicious code and remediate the compromised credentials.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the Sigma rule \u0026quot;AWS S3 Static Site JavaScript File Upload\u0026quot; to your SIEM and tune for your specific environment (see rule below).\u003c/li\u003e\n\u003cli\u003eInvestigate any alerts generated by the Sigma rule, focusing on the \u003ccode\u003eaws.cloudtrail.user_identity.arn\u003c/code\u003e, access key ID, and session type.\u003c/li\u003e\n\u003cli\u003eReview the content of uploaded JavaScript files using S3 \u003ccode\u003eGetObject\u003c/code\u003e or CloudTrail \u003ccode\u003erequestParameters\u003c/code\u003e to identify potentially malicious code.\u003c/li\u003e\n\u003cli\u003eAudit IAM policies to ensure that only authorized users and roles have write access to S3 buckets hosting static websites.\u003c/li\u003e\n\u003cli\u003eEnable S3 bucket versioning to facilitate quick rollback and historical review of file modifications.\u003c/li\u003e\n\u003cli\u003eMonitor AWS CloudTrail logs for \u003ccode\u003ePutObject\u003c/code\u003e events targeting S3 buckets containing static website content.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-02T12:00:00Z","date_published":"2024-01-02T12:00:00Z","id":"https://feed.craftedsignal.io/briefs/2024-01-02-aws-s3-static-site-js-upload/","summary":"Detection of a JavaScript file upload to an AWS S3 static website directory by an IAM user or assumed role, potentially indicating malicious web content modification and frontend compromise.","title":"Suspicious JavaScript File Upload to AWS S3 Static Website","url":"https://feed.craftedsignal.io/briefs/2024-01-02-aws-s3-static-site-js-upload/"}],"language":"en","title":"CraftedSignal Threat Feed - AWS CloudFront","version":"https://jsonfeed.org/version/1.1"}