{"description":"Trending threats, MITRE ATT\u0026CK coverage, and detection metadata — refreshed continuously.","feed_url":"https://feed.craftedsignal.io/tags/yuze/","home_page_url":"https://feed.craftedsignal.io/","items":[{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Defender XDR","Elastic Defend","Elastic Endgame"],"_cs_severities":["medium"],"_cs_tags":["command-and-control","tunneling","yuze","proxy"],"_cs_type":"advisory","_cs_vendors":["Microsoft","Elastic","Crowdstrike","SentinelOne"],"content_html":"\u003cp\u003eThis rule detects the execution of Yuze, an open-source tunneling tool written in C, which is commonly used for intranet penetration. Yuze supports both forward and reverse SOCKS5 proxy tunneling and is often executed using \u003ccode\u003erundll32\u003c/code\u003e to load \u003ccode\u003eyuze.dll\u003c/code\u003e with the \u003ccode\u003eRunYuze\u003c/code\u003e export. Threat actors can leverage Yuze to proxy command and control (C2) communications or to pivot within a network. The detection focuses on identifying processes with command-line arguments indicative of Yuze execution, specifically those involving \u0026ldquo;reverse,\u0026rdquo; \u0026ldquo;-c,\u0026rdquo; \u0026ldquo;proxy,\u0026rdquo; \u0026ldquo;fwd,\u0026rdquo; and \u0026ldquo;-l\u0026rdquo; parameters. This activity has been observed in real-world campaigns, increasing the importance of timely detection and response.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eThe attacker gains initial access to a target system through various means (e.g., phishing, exploitation of vulnerabilities).\u003c/li\u003e\n\u003cli\u003eThe attacker uploads or drops the \u003ccode\u003eyuze.dll\u003c/code\u003e file onto the compromised host.\u003c/li\u003e\n\u003cli\u003eThe attacker uses \u003ccode\u003erundll32.exe\u003c/code\u003e to execute \u003ccode\u003eyuze.dll\u003c/code\u003e, calling the \u003ccode\u003eRunYuze\u003c/code\u003e export.\u003c/li\u003e\n\u003cli\u003eThe command line includes parameters to establish a reverse or forward SOCKS5 proxy tunnel (e.g., \u003ccode\u003erundll32 yuze.dll,RunYuze reverse -c \u0026lt;ip\u0026gt;:\u0026lt;port\u0026gt;\u003c/code\u003e).\u003c/li\u003e\n\u003cli\u003eYuze establishes a tunnel to a remote server, allowing the attacker to proxy network traffic.\u003c/li\u003e\n\u003cli\u003eThe attacker uses the established tunnel to pivot within the network and access internal resources.\u003c/li\u003e\n\u003cli\u003eThe attacker may proxy C2 traffic through the tunnel, masking the true origin of the commands.\u003c/li\u003e\n\u003cli\u003eThe attacker performs actions on the internal network, such as data exfiltration or lateral movement, using the tunnel as a covert channel.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation allows attackers to establish covert communication channels, bypass network security controls, and proxy malicious traffic, potentially leading to unauthorized access to sensitive data, lateral movement within the network, and data exfiltration. The use of Yuze can obscure the origin of attacks, making attribution more difficult and hindering incident response efforts.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the Sigma rule \u0026ldquo;Potential Yuze Tunneling via Rundll32\u0026rdquo; to your SIEM to detect the execution of \u003ccode\u003eyuze.dll\u003c/code\u003e via \u003ccode\u003erundll32.exe\u003c/code\u003e with specific command-line arguments.\u003c/li\u003e\n\u003cli\u003eEnable process creation logging (Sysmon Event ID 1 or Windows Security Auditing) to capture the necessary command-line information for the Sigma rules.\u003c/li\u003e\n\u003cli\u003eInvestigate any identified instances of \u003ccode\u003erundll32.exe\u003c/code\u003e executing \u003ccode\u003eyuze.dll\u003c/code\u003e, focusing on the parent processes and network connections.\u003c/li\u003e\n\u003cli\u003eBlock the C2/relay IP or domain found in the \u003ccode\u003e-c\u003c/code\u003e argument at DNS/firewall, as described in the Triage and Analysis section of the rule\u0026rsquo;s note.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-02T12:00:00Z","date_published":"2024-01-02T12:00:00Z","id":"/briefs/2024-01-yuze-tunneling/","summary":"This alert detects potential protocol tunneling activity via the execution of Yuze, a lightweight open-source tunneling tool often used by threat actors for intranet penetration via forward and reverse SOCKS5 proxy tunneling.","title":"Potential Protocol Tunneling via Yuze","url":"https://feed.craftedsignal.io/briefs/2024-01-yuze-tunneling/"}],"language":"en","title":"CraftedSignal Threat Feed — Yuze","version":"https://jsonfeed.org/version/1.1"}