Query: alert when Detects network connections to Cloudflared tunnels domains initiated by a process on the system. Attackers can abuse tha
Matching passage: Sigma rule: Detects network connections to Cloudflared tunnels domains initiated by a process on the system. Attackers can abuse tha. Logsource: windows / network_connection. Rule: title: Network Connection Initiated To Cloudflared Tunnels Domains id: 7cd1dcdc-6edf-4896-86dc-d1f19ad64903 related: - id: a1d9eec5-33b2-4177-8d24-27fe754d0812 type: derived status: test description: 'Detects network connections to Cloudflared tunnels domains initiated by a process on the system. Attackers can abuse that feature to establish a reverse shell or persistence on a machine. ' references: - https://defr0ggy.github.io/research/Abusing-Cloudflared-A-Proxy-Service-To-Host-Share-Applications/ - https://www.guidepointsecurity.com/blog/tunnel-vision-cloudflared-abused-in-the-wild/ - Internal Research author: Kamran Saifullah, Nasreddine Bencherchali (Nextron Systems) date: 2024-05-27 tags: - attack.exfiltration - attack.command-and-control - attack.t1567 - attack.t1572 logsource: category: network_connection product: windows detection: selection: Initiated: 'true' DestinationHostname|endswith: - .v2.argotunnel.com - protocol-v2.argotunnel.com - trycloudflare.com - update.argotunnel.com condition: selection falsepositives: - Legitimate use of cloudflare tunnels will also trigger this. level: medium
Near-miss passage: Sigma rule: Detects exploitation of LNK file command-line length discrepancy, where attackers hide malicious commands beyond the 260. Logsource: windows / process_creation. Rule: title: Suspicious LNK Command-Line Padding with Whitespace Characters id: dd8756e7-a3a0-4768-b47e-8f545d1a751c status: experimental description: 'Detects exploitation of LNK file command-line length discrepancy, where attackers hide malicious commands beyond the 260-character UI limit while the actual command-line argument field supports 4096 characters using whitespace padding (e.g., 0x20, 0x09-0x0D). Adversaries insert non-printable whitespace characters (e.g., Line Feed \x0A, Carriage Return \x0D) to pad the visible section of the LNK file, pushing malicious commands past the UI-visible boundary. The hidden payload, executed at runtime but invisible in Windows Explorer properties, enables stealthy execution and evasion—commonly used for social engineering attacks. This rule flags suspicious use of such padding observed in real-world attacks. ' references: - https://syedhasan010.medium.com/forensics-analysis-of-an-lnk-file-da68a98b8415 - https://thehackernews.com/2025/03/unpatched-windows-zero-day-flaw.html - https://www.trendmicro.com/en_us/research/25/c/windows-shortcut-zero-day-exploit.html author: Swachchhanda Shrawan Poudel (Nextron Systems) date: 2025-03-19 tags: - attack.initial-access - attack.execution - attack.t1204.002 logsource: category: process_creation product: windows detection: selection_img: - ParentImage|endswith: \explorer.exe - ParentCommandLine|contains: .lnk selection_cmd: - CommandLine|contains: - ' ' - \u0009 - \u000A - \u0011 - \u0012 - \u0013 - \u000B - \u000C - \u000D - CommandLine|re: \n\n\n\n\n\n condition: all of selection_* falsepositives: - Unknown level: high