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Dylan Evans

@decksy
Completionist
13 followers74 downloads294 copies46 likes3,043 views

15 detections

Detects network connections to blockchain APIs that are indicative of EtherHiding techniques, specifically those used by UNC5342 to retrieve malicious payloads. It identifies connections to domains containing keywords like 'explorer', 'block', 'cypher', 'eth', 'bit', 'coin', or 'crypto', combined with suspicious URL patterns such as 'eth_call' (a read-only function call for smart contracts) or 'apiKey=freekey' (a common free API key used by threat actors).
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Dylan Evans@decksy
Dexter's Laboratory
1 year ago
665645
This rule identifies unusual activity from locations not previously observed for a user within a defined lookback period. It leverages Microsoft Entra ID (Azure AD) Behavior Analytics and SigninLogs to baseline legitimate user locations and filter out trusted devices/IPs. The rule flags unusual activity where the source IP location is new for the user and exceeds a configurable threshold of 'unusual' behavior indicators, while also excluding specified trusted countries.
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Dylan Evans@decksy
Dexter's Laboratory
1 year ago
549595
This rule detects network connections to known dynamic DNS (DDNS) subdomains. Adversaries often use dynamic DNS services to maintain persistent command and control (C2) communication channels, as these services allow them to frequently change the IP address associated with a static hostname, making it harder for defenders to block or track their infrastructure. These providers also have established domain reputation, and provide legitimate services making blanket IOC rules impossible. The rule identifies connections to specific DDNS providers such as DuckDNS, No-IP, PublicVM, and others.
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Dylan Evans@decksy
Dexter's Laboratory
1 year ago
143176
Detects activity related to the PromptLock ransomware, which leverages the Ollama AI API and is written in Go. This rule looks for network connections to the Ollama service (port 11434) and related process executions, specifically identifying processes like go.exe, curl.exe, wget.exe, python.exe, powershell.exe making connections or processes with 'ollama' in their command line.
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Dylan Evans@decksy
Dexter's Laboratory
1 year ago
165245
This rule detects suspicious bulk file downloads from SharePoint by correlating successful sign-in events with subsequent file download activities. It specifically looks for sign-ins that are not from registered devices, followed by multiple file downloads (at least 3) within a short time window (up to 10 minutes) from the same IP address. The rule flags scenarios where a user downloads a significant number of unique files (at least 2) or has a high download count (5 or more), or a combination of moderate downloads (3 or more) within a very short duration (1 minute). This pattern can indicate data exfiltration attempts.
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Dylan Evans@decksy
Dexter's Laboratory
1 year ago
7913461
This rule detects the creation of new Microsoft Power Automate flows that are configured to use connectors capable of exfiltrating data via email or collaboration platforms like Microsoft Teams. It specifically looks for flows created with connectors which could indicate an attempt to send sensitive information outside the organization.
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Dylan Evans@decksy
Dexter's Laboratory
1 year ago
90177
This rule detects processes that are taking an unusually high number of screenshots within a defined timeframe. It identifies screenshot activity by looking for specific action types like "ScreenshotTaken", file creations with common image extensions (.png, .jpg, .jpeg, .bmp, .gif, .tiff), and process command lines containing common Windows API calls related to screen capturing (e.g., BitBlt, GetDC, PrintWindow, CopyFromScreen). The rule aggregates these events per device and triggers an alert if the total number of screenshots exceeds a configurable threshold.
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Dylan Evans@decksy
Dexter's Laboratory
1 year ago
13381
This rule detects suspicious process and file activity that may be indicative of a crypto-miner or other malware. Specifically, it looks for the execution of VBScript files with a specific naming convention ('x#######.vbs') via wscript, or batch files with a similar naming convention initiated by wscript. Additionally, it unions these process events with file events where 'printui.exe' or 'printui.dll' are found in 'C:\Windows \System32\'. The rule then summarizes these events by device and flags if both process and file events are observed on the same device within the specified timeframes, suggesting a multi-stage activity.
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Dylan Evans@decksy
Dexter's Laboratory
1 year ago
1032
This rule detects network connections, email activity, URL clicks, and Teams messages that involve domains commonly used by threat actor group Scattered Spider. It specifically looks for domains containing '-servicedesk.', '-okta.', '-sso.', '-cms.', '-helpdesk.', or 'oktalogin-'. The rule aims to identify potential phishing attempts or suspicious activity targeting SSO/helpdesk credentials by monitoring interactions with these specific domain patterns across multiple data sources.
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Dylan Evans@decksy
Dexter's Laboratory
1 year ago
132186
This rule detects potential data exfiltration attempts using the built-in Windows `ping.exe` utility. Specifically, it looks for `ping.exe` executions where a large payload size (greater than 1024 bytes) is specified using the -L command-line argument. This technique can be used to tunnel data over ICMP, which might bypass some network defenses.
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Dylan Evans@decksy
Dexter's Laboratory
1 year ago
153110
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