Name:HTTP Possible Request Smuggling id:97d85f98-9d15-41a0-8682-7030454875e7 version:5 date:None author:Raven Tait, Splunk status:production type:TTP Description:HTTP request smuggling is a technique for interfering with the way a web site processes sequences of HTTP requests that are received from one or more users. Request smuggling vulnerabilities are often critical in nature, allowing an attacker to bypass security controls, gain unauthorized access to sensitive data, and directly compromise other application users. This detection identifies a common request smuggling technique of using both Content-Length and Transfer-Encoding headers to cause a parsing confusion between the frontend and backend. Data_source:
-Suricata
search:`suricata` (http.request_headers{}.name="*Content-Length*" http.request_headers{}.name="*Transfer-Encoding*") OR (http.request_headers{}.name="*Content-Length*" http.request_headers{}.value="*Transfer-Encoding*") OR (http.request_headers{}.value="*Content-Length*" http.request_headers{}.name="*Transfer-Encoding*") OR (http.request_headers{}.name="*Content-Length*" http.request_headers{}.value="0")
| rename dest_ip as dest
| rex field=_raw "request_headers.:\[(?<headers>.*)\]"
| stats count min(_time) as firstTime max(_time) as lastTime BY dest, dest_port, src_ip, http.url, http.http_method, http.http_user_agent, http.protocol, http.status, headers
| `security_content_ctime(firstTime)`
| `security_content_ctime(lastTime)`
| `http_possible_request_smuggling_filter`
how_to_implement:This detection requires the Web datamodel to be populated from a supported Technology Add-On like Suricata, Splunk for Apache, Splunk for Nginx, or Splunk for Palo Alto. Some of these will need to have all headers dumped to contain the necessary fields. known_false_positives:False positives are not expected, however, monitor, filter, and tune as needed based on organization log sources. References: -https://portswigger.net/web-security/request-smuggling#what-is-http-request-smuggling -https://portswigger.net/research/http1-must-die -https://www.vaadata.com/blog/what-is-http-request-smuggling-exploitations-and-security-best-practices/ -https://www.securityweek.com/new-http-request-smuggling-attacks-impacted-cdns-major-orgs-millions-of-websites/ drilldown_searches: name:'View the detection results for - "$dest$"' search:'%original_detection_search% | search dest = "$dest$"' earliest_offset:'$info_min_time$' latest_offset:'$info_max_time$' name:'View risk events for the last 7 days for - "$dest$"' search:'| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$dest$") | stats count min(_time) as firstTime max(_time) as lastTime values(search_name) as "Search Name" values(risk_message) as "Risk Message" values(analyticstories) as "Analytic Stories" values(annotations._all) as "Annotations" values(annotations.mitre_attack.mitre_tactic) as "ATT&CK Tactics" by normalized_risk_object | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`' earliest_offset:'7d' latest_offset:'0' analytic_story:['HTTP Request Smuggling']
