{"description":"Trending threats, MITRE ATT\u0026CK coverage, and detection metadata. Fed continuously.","feed_url":"https://feed.craftedsignal.io/tags/user-agent/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":["Nginx","Apache HTTP Server","Apache Tomcat","IIS","Traefik"],"_cs_severities":["low"],"_cs_tags":["web-server","reconnaissance","vulnerability-scanning","user-agent"],"_cs_type":"advisory","_cs_vendors":["Nginx","Apache","Microsoft","Traefik"],"content_html":"\u003cp\u003eThis rule detects unusual spikes in web server requests with uncommon or suspicious user-agent strings, which may indicate reconnaissance attempts by attackers trying to identify vulnerabilities in web applications or servers. These user-agents are often associated with automated tools used for scanning, vulnerability assessment, or brute-force attacks. The rule is designed to detect activity from tools like Nikto, Nessus, SQLMap, WPScan, Feroxbuster, Masscan, Ffuf, Dirsearch, Dirb, Dirbuster, Gobuster, Nmap, Hydra, w3af, Arachni, Skipfish, OpenVAS, Acunetix, ZAP, and Burp Suite. It analyzes logs from web servers such as Nginx, Apache, Apache Tomcat, IIS, and Traefik, looking for a high volume of requests with diverse URLs originating from a single source IP address.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAttacker uses a scanning tool (e.g., Nikto, WPScan, Dirsearch) to send HTTP requests to the target web server.\u003c/li\u003e\n\u003cli\u003eThe scanning tool employs a specific User-Agent header that identifies it (e.g., \u0026quot;nikto\u0026quot;, \u0026quot;wpscan\u0026quot;).\u003c/li\u003e\n\u003cli\u003eThe web server logs the HTTP requests, including the source IP address, User-Agent, and requested URL.\u003c/li\u003e\n\u003cli\u003eThe attacker's tool iterates through numerous URLs, probing for common vulnerabilities, hidden paths, or administrative interfaces.\u003c/li\u003e\n\u003cli\u003eThe web server responds to each request, generating distinct log entries for each URL accessed.\u003c/li\u003e\n\u003cli\u003eThe rule detects an unusual spike in requests with suspicious user agents from a single source IP within a defined time interval.\u003c/li\u003e\n\u003cli\u003eIf successful, the attacker gains information about the web server's configuration, software versions, and potential vulnerabilities.\u003c/li\u003e\n\u003cli\u003eThe attacker may then exploit these vulnerabilities to gain unauthorized access or control.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful reconnaissance can lead to the discovery of vulnerabilities in web applications, potentially allowing attackers to gain unauthorized access, escalate privileges, or exfiltrate sensitive data. While this rule flags potential reconnaissance activity, it does not directly indicate a successful breach. The impact can range from minor information leakage to complete system compromise, depending on the vulnerabilities discovered and exploited. Organizations can experience data breaches, service disruptions, and reputational damage if attackers successfully leverage the information gathered during reconnaissance.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the Sigma rule \u003ccode\u003eWeb Server Suspicious User Agent - High Volume\u003c/code\u003e to detect high-volume scanning activity based on user-agent strings.\u003c/li\u003e\n\u003cli\u003eEnable logging for web servers, including Nginx, Apache, Apache Tomcat, IIS, and Traefik, to ensure the \u003ccode\u003eprocess_creation\u003c/code\u003e log source is available.\u003c/li\u003e\n\u003cli\u003eInvestigate any alerts generated by the Sigma rules to determine if the detected activity is legitimate vulnerability scanning or malicious reconnaissance attempts.\u003c/li\u003e\n\u003cli\u003eImplement rate limiting and blocking mechanisms for suspicious IP addresses detected by the Sigma rule at the WAF/CDN or edge firewall.\u003c/li\u003e\n\u003cli\u003eMonitor web server access logs for requests matching the user-agent strings listed in the rule's query section.\u003c/li\u003e\n\u003cli\u003eImplement WAF signatures for known scanner user agents to prevent malicious reconnaissance attempts.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-03T12:00:00Z","date_published":"2024-01-03T12:00:00Z","id":"https://feed.craftedsignal.io/briefs/2024-01-web-reconnaissance/","summary":"Detection of unusual spikes in web server requests with uncommon or suspicious user-agent strings indicative of reconnaissance attempts to identify web application vulnerabilities or brute-force attacks.","title":"Web Server Reconnaissance via Unusual User Agents","url":"https://feed.craftedsignal.io/briefs/2024-01-web-reconnaissance/"}],"language":"en","title":"CraftedSignal Threat Feed - User-Agent","version":"https://jsonfeed.org/version/1.1"}