# Analyzing Proxy Scanner Activity: Monitoring /proxy/ URI Patterns > Threat actors are shifting scanning patterns to identify open proxies using /proxy/ URI prefixes. Learn how to detect and mitigate these reconnaissance scans. - Published: 2026-03-16T16:31:05.000Z - Severity: medium - Category: Threat Intel - Tags: Proxy Scanning, Reconnaissance, Web Server Security, Honeypot Analysis, URI Patterns - Author: Runtime Rebel Intel - Primary source: https://isc.sans.edu/diary/rss/32800 - Canonical: https://runtimerebel.com/blog/analyzing-proxy-scanner-activity-monitoring-proxy-uri-patterns ## Key points - Immediate impact: Attackers are scanning for misconfigured web servers to use as open proxies for anonymizing malicious activities. - Affected systems: Any web server or gateway exposed to the internet, particularly those with proxy-related URI handlers or misconfigurations. - Remediation: Implement strict URI filtering and monitor access logs for unusual requests containing the /proxy/ prefix followed by external IP addresses. ## Overview of Observed Proxy Scanning Activity Recent honeypot data indicates a persistent interest in identifying open proxy servers across the internet. While scanning for open proxies is a staple of internet-wide reconnaissance, a specific shift in [TTP](/glossary#ttp) has been identified by researchers at the [SANS Internet Storm Center (ISC)](https://isc.sans.edu/diary/rss/32800). The current trend focuses on URI paths beginning with the `/proxy/` prefix, often followed by specific IP addresses, suggesting a targeted effort to find misconfigured gateway services. This activity represents a common phase in the cyber-attack lifecycle where actors seek infrastructure to anonymize their source [C2](/glossary#c2) traffic or bypass geographic restrictions. While no specific [CVE](/glossary#cve) is tied to this general scanning, the methodology targets architectural weaknesses in web server configurations and proxy modules. Identifying these patterns early is essential for preventing your infrastructure from becoming a relay for malicious traffic. ## Technical Analysis of /proxy/ URI Scans The scanning pattern typically involves HTTP GET or CONNECT requests directed at a web server. Traditionally, scanners might attempt to inject a Host header or include a full URL in the request line to see if the server forwards the request to an external destination. However, the observed pattern of **analyzing /proxy/ URI web scans** shows attackers targeting systems that may have pre-defined proxy endpoints or default routes configured. The use of the `/proxy/` prefix is significant because many enterprise applications, development frameworks, and API gateways use this string as a conventional route for internal or external request forwarding. When a scanner requests a path like `/proxy/1.2.3.4`, they are testing whether the server is configured to relay traffic to the trailing IP address. If the server responds with the content of the external IP, the attacker has successfully identified an open relay. ### Detecting Proxy Server Scanning Patterns For defensive teams, **detecting proxy server scanning patterns** requires high-fidelity visibility into web access logs. Many standard [EDR](/glossary#edr) solutions may not capture the full URI of web requests unless they are integrated with server-side logging or web application firewall (WAF) telemetry. Therefore, a [SOC](/glossary#soc) must rely on [SIEM](/glossary#siem) ingestion of logs from Nginx, Apache, or load balancers to identify these probes. A key indicator of this activity is the presence of an IP address within the URI path immediately following the `/proxy/` keyword. Legitimate application traffic rarely follows this format. If your logs show frequent 404 or 403 errors associated with these paths, it is a strong signal that an automated scanner is probing your perimeter for vulnerabilities that could lead to unauthorized [Lateral Movement](/glossary#lateral-movement) or data exfiltration. ## Strategic Risks and Impact An identified open proxy is a valuable asset for a threat actor. Beyond simply hiding their origin, attackers can use these systems to perform credential stuffing, launch a [DDoS](/glossary#ddos) attack, or facilitate more complex [Phishing](/glossary#phishing) campaigns where the URL appears to originate from a trusted domain. This effectively turns a legitimate corporate server into a weapon for further exploitation. From a [MITRE ATT&CK](/glossary#mitre-att-ck) perspective, this activity falls under Reconnaissance (T1595). While it may appear as background noise, ignoring these scans can lead to significant reputational and operational risks. If your infrastructure is leveraged in a third-party breach, your IP space may be blacklisted by global threat intelligence feeds, impacting legitimate business communication. ## Mitigation and Recommendations The primary defense against this activity is ensuring that your web infrastructure does not act as an open relay. Defenders should prioritize the following actions: * **Disable Unnecessary Proxying:** Review configuration files (e.g., `httpd.conf`, `nginx.conf`) and ensure that directives such as `ProxyRequests` are set to `Off` unless required for specific business functions. * **Implement URI Filtering:** Configure your WAF or load balancer to block requests containing the `/proxy/` string unless it matches a strictly defined whitelist of legitimate application endpoints. * **Apply Zero Trust Principles:** Adopt a [Zero Trust](/glossary#zero-trust) architecture where internal services are never exposed to the public internet via simple proxy relays without robust authentication and authorization. * **Monitor High-Risk Patterns:** Create alerts in your log management platform for URI paths that contain IP addresses or external domain names following common proxy-related keywords. By understanding **how to block open proxy exploitation**, organizations can reduce their attack surface and prevent their resources from being co-opted into larger botnet infrastructures. Monitoring for these specific URI patterns should be an integral part of any proactive threat hunting routine to maintain perimeter integrity. **Related:** [Automated Reconnaissance Targeting React2Shell Implementations](/blog/automated-reconnaissance-targeting-react2shell-implementations), [CyberStrikeAI Exploitation: AI Tools Targeting Fortinet Firewalls](/blog/cyberstrikeai-exploitation-ai-tools-targeting-fortinet-firewalls) --- AI-generated analysis from the primary source above; not human-reviewed before publication — verify anything operational against the original (https://runtimerebel.com/editorial). Quote with attribution and a link to the canonical URL: https://runtimerebel.com/blog/analyzing-proxy-scanner-activity-monitoring-proxy-uri-patterns