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Arnold Chan

@slaz
Trusted contributorCompletionist
2 followers2,099 downloads4,375 copies51 likes26,085 views

7,555 detections

Detects PE binaries masquerading as Microsoft's Windows Update Assistant via forged VersionInfo metadata combined with an unsigned or invalid/unverified digital signature, associated with HVNC backdoor delivery
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Arnold Chan@slaz
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Detections.ai Community
2 months ago
003
Detects the creation of specific mutex objects ('AppUpdateHelper' or 'WinSvc') commonly associated with Hidden VNC (hVNC) backdoors. These mutexes are used by the malware to ensure only one instance is running on the host, and the regex pattern targets the specific naming convention (including a hex suffix) utilized by these threats.
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Arnold Chan@slaz
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Detection & Hunting Community
2 months ago
003
Detects the Silver Fox HVNC malware dropper initiating browser instances via the command line to access known malicious C2 domains or infrastructure. The rule specifically monitors for known malicious binaries (UpdateAssistant.exe, AppUpdateHelper.exe, SysMaintenance.exe) launching browsers with suspicious command-line parameters associated with this campaign.
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Arnold Chan@slaz
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Detection & Hunting Community
2 months ago
003
Detects anomalous authentication behavior where a user account utilizes the same authentication session (LogonId) or material to authenticate across multiple distinct destination hosts in a short timeframe. This rule monitors for both NTLM (Type 3) and Kerberos (TGS/TGT) events, which are indicative of lateral movement techniques such as Pass-the-Hash or Pass-the-Ticket.
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Arnold Chan@slaz
Defender - KQL
2 months ago
104
Detects a specific pattern of PowerShell execution involving the download of files from a remote endpoint using parameters associated with Brazilian tax documents (NotaFiscal) to the Desktop directory, followed by immediate execution. The rule looks for a combination of hidden window style, Invoke-WebRequest, specific URL parameters (dl.php, NFe identifiers), and subsequent Start-Process calls, which is indicative of malware dropper activity.
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Arnold Chan@slaz
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Midnight Slayer
2 months ago
003
Detects a specific pattern of PowerShell execution involving the download of files from a remote endpoint using parameters associated with Brazilian tax documents (NotaFiscal) to the Desktop directory, followed by immediate execution. The rule looks for a combination of hidden window style, Invoke-WebRequest, specific URL parameters (dl.php, NFe identifiers), and subsequent Start-Process calls, which is indicative of malware dropper activity.
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Arnold Chan@slaz
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Detections.ai Community
2 months ago
103
Detects suspicious PowerShell execution initiated by explorer.exe containing encoded commands, correlated with concurrent activity in the Windows RunMRU registry key or execution of rundll32.exe referencing 'WindowsUpdate.log'. This pattern is frequently used to mask malicious activity and maintain stealth during fileless execution or persistence operations.
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Arnold Chan@slaz
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Detections.ai Community
2 months ago
003
Detects anomalous, non-interactive sign-in activity in Microsoft 365 that suggests session cookie replay (Pass-the-Cookie). The rule correlates successful, MFA-validated interactive sign-ins against subsequent, non-interactive sign-ins that lack MFA, occur from a different device and IP address within a short time window, and bypass standard interactive re-authentication.
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Arnold Chan@slaz
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Midnight Slayer
2 months ago
103
Detects the PoisonedRefresh implant's UNIX domain socket backdoor by (1) file activity on the uniquely-named /run/bigtlog.pipe socket initiated by an Apache/httpd process, and (2) process command lines containing the implant's hardcoded authentication token. Removed the earlier generic 'bash spawned by httpd' heuristic, which fired on legitimate CGI/mod_php/admin automation that shells out from the web server and was the dominant false-positive source.
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Arnold Chan@slaz
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Detections.ai Community
2 months ago
104
Detects the creation of an NTUSER.MAN file followed by an update or creation of a registry run key (Run or RunOnce) on the same device within a 60-minute window. NTUSER.MAN is a mandatory user profile file that, when present, can be used to override user settings and persist malicious configurations or startup entries.
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Arnold Chan@slaz
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Midnight Slayer
2 months ago
005
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