TLP:RED // CDB-GOC STRATEGIC INTELLIGENCE ADVISORY // SENTINEL APEX v15.0

CYBERDUDEBIVASH SENTINEL APEX™ // PREMIUM THREAT INTELLIGENCE ADVISORY

The Notepad++ supply chain attack — unnoticed execution chains and new IoCs

Advanced Threat Intelligence Advisory by CyberDudeBivash Sentinel APEX™ — AI-Powered Global Threat Intelligence Infrastructure

1. EXECUTIVE SUMMARY (CISO / BOARD READY)

Overview

The CyberDudeBivash Global Operations Center (GOC) has identified and analyzed a significant cybersecurity event classified as a Malware Campaign / Threat Actor Operation with a dynamic risk score of 10.0/10 (CRITICAL). This advisory covers the threat designated as "The Notepad++ supply chain attack — unnoticed execution chains and new IoCs", attributed to tracking cluster UNC-CDB-99.

Chain #1: late July and early August 2025 Return of chain #2 and changes in URLs: October 2025 UPD 11.02.2026: added recommendations on how to use the Notepad++ supply chain attack rules package in our SIEM system.

The Sentinel APEX AI Engine has processed all available intelligence, extracting 68 indicators of compromise across 5 categories. IOC confidence is assessed at 78.0% based on indicator diversity, source reliability, and actor attribution strength. Security teams in the Enterprise, Financial Services, Government sectors should treat this advisory as an actionable intelligence requirement.

Business Risk Implications: Organizations exposed to this threat face potential impacts across multiple dimensions including operational disruption, financial losses from incident response and remediation costs, reputational damage from public disclosure, and regulatory penalties under applicable data protection frameworks. Security leaders should evaluate this advisory against their organization's risk appetite and threat exposure profile, engaging executive stakeholders as appropriate based on the assessed severity level. The recommended response actions are detailed in Sections 9, 10, and 11 of this report.

Strategic Impact Assessment

This threat poses immediate risk to business continuity, data integrity, and organizational reputation. Financial exposure from potential data breach, regulatory penalties, and operational disruption could be substantial. Organizations in the Enterprise, Financial Services, Government sectors face heightened exposure due to the nature of this threat. Regulatory implications under frameworks including GDPR, HIPAA, PCI-DSS, and sector-specific mandates should be evaluated by compliance teams.

2. THREAT LANDSCAPE CONTEXT

Campaign Background

This campaign operates within the broader context of malware campaign / threat actor operation activity that has been observed across the global threat landscape. Intelligence analysis indicates that threat actors continue to evolve their tactics, techniques, and procedures (TTPs) to exploit emerging vulnerabilities, misconfigured infrastructure, and human factors.

Return of chain #2 and changes in URLs: October 2025 UPD 11.02.2026: added recommendations on how to use the Notepad++ supply chain attack rules package in our SIEM system. On February 2, 2026, the developers of Notepad++, a text editor popular among developers, published a statement claiming that the update infrastructure of Notepad++ had been compromised. According to the statement, this was due to a hosting provider-level incident, which occurred from June to September 2025. However, attackers had been able to retain access to internal services until December 2025. Having checked our telemetry related to this incident, we were amazed to find out how different and unique the execution chains used in this supply chain attack were. We identified that over the course of four months, from July to October 2025, attackers who had compromised Notepad++ had been constantly rotating C2 server addresses used for distributing malicious updates, the downloaders used for implant delivery, as well as the final payloads.

The CyberDudeBivash GOC tracks this activity under its institutional tracking framework, correlating indicators across multiple intelligence sources to establish campaign attribution and scope. Historical analysis suggests that campaigns of this nature frequently target organizations with inadequate patch management, legacy authentication mechanisms, and limited visibility into endpoint and network telemetry.

Regional targeting patterns indicate that threat actors associated with this type of activity operate opportunistically, leveraging automated scanning and exploitation tools to identify vulnerable targets across geographic boundaries. The increasing commoditization of attack tooling has lowered the barrier to entry for threat actors, resulting in a broader range of organizations facing exposure to sophisticated attack methodologies that were previously limited to nation-state operations.

Threat Actor Profile

Attribution Reconciliation: The CyberDudeBivash GOC employs an institutional tracking framework (UNC-CDB-99) for internal campaign correlation and continuity. This identifier maps to the community-recognized designations listed under Aliases above, as reported by OSINT researchers and threat intelligence vendors including Mandiant, CrowdStrike, Microsoft, and Group-IB. Organizations may use either the CDB tracking identifier or any recognized community alias for cross-platform intelligence sharing and ISAC coordination.

3. TECHNICAL ANALYSIS (DEEP-DIVE)

3.1 Infection Chain Reconstruction

This malware campaign employs a sophisticated multi-stage infection chain designed to maximize persistence and evade detection. The initial delivery vector involves dropper components that download and execute the primary payload in memory, avoiding disk-based detection signatures.

The payload implements anti-analysis techniques including virtual machine detection, debugger detection, and time-based evasion to resist automated sandbox analysis. Persistence mechanisms include registry run key modifications, DLL search order hijacking, and COM object hijacking. Data staging and exfiltration occur through encrypted HTTPS channels to distributed C2 infrastructure operating across multiple autonomous systems.

3.2 Malware / Payload Analysis

Analysis of associated indicators reveals technical characteristics consistent with malware campaign / threat actor operation operations. Malicious artifacts detected include: 1.dll, AutoUpdater.exe, BluetoothService.exe, GUP.exe, ProShow.exe. These file indicators should be blocked at endpoint and email gateway levels.

Behavioral analysis indicates the use of process injection techniques, API hooking for credential interception, and encrypted communication channels for data exfiltration. The malware demonstrates anti-analysis capabilities including environment fingerprinting and delayed execution to evade sandbox detection. Registry modifications are used for persistence, with backup mechanisms employing scheduled task creation to ensure survivability across system reboots.

3.3 Infrastructure Mapping

Infrastructure analysis identifies 2 IP address(es) and 15 domain(s) associated with this campaign. Network indicators suggest the use of distributed infrastructure across multiple autonomous systems and geographic regions, consistent with bulletproof hosting arrangements or compromised legitimate infrastructure. Domain registration patterns and SSL certificate analysis may reveal additional connected infrastructure through pivoting techniques. Organizations should monitor for connections to these indicators and investigate any historical connections in network logs.

4. INDICATORS OF COMPROMISE (IOC SECTION)

Structured IOC Table

Detection Recommendations

• Network Layer: Block identified IP addresses and domains at firewall and DNS proxy level. Implement DNS sinkholing for known malicious domains to prevent C2 callbacks.
• Endpoint Layer: Deploy YARA rules for file-based detection. Configure EDR behavioral rules to detect suspicious process execution, living-off-the-land binaries (LOLBins), and anomalous PowerShell or script interpreter activity.
• Email Security: Update email gateway rules to detect associated phishing patterns. Implement DMARC/SPF/DKIM enforcement for impersonated domains.
• SIEM Correlation: Integrate the provided Sigma rules into SIEM platforms for real-time alerting. Correlate network IOCs with endpoint telemetry for campaign detection.

5. MITRE ATT&CK® MAPPING

The following MITRE ATT&CK® techniques have been identified through automated analysis of the threat intelligence associated with this campaign. Each technique represents a documented adversary behavior that defenders can use to build detection and response capabilities.

6. DETECTION ENGINEERING (SOC READY)

6.1 Sigma Rules

The following Sigma rule provides SIEM-agnostic detection capability for this campaign. Deploy to Microsoft Sentinel, Splunk, Elastic, or any Sigma-compatible platform.

title: 'CDB-Sentinel: The Notepad supply chain attack  unnoticed execution chains
  and new IoCs - Network IOCs'
id: cdb-123225
status: experimental
description: 'Detects network connections to infrastructure associated with: The Notepad
  supply chain attack  unnoticed execution chains and new IoCs. Auto-generated by
  CyberDudeBivash Sentinel APEX.'
references:
- https://cyberdudebivash.com
- https://cyberbivash.blogspot.com
author: CyberDudeBivash GOC (Automated)
date: 2026/02/17
tags:
- attack.command_and_control
- attack.exfiltration
logsource:
  category: dns
  product: any
detection:
  selection_dns:
    query|contains:
    - 1.txt
    - a.txt
    - alien.ini
    - api.skycloudcenter
    - api.wiresguard
    - api.wiresguard.com
    - cdncheck.it
    - cdncheck.it.com
  condition: selection_dns
falsepositives:
- Legitimate traffic to similarly named domains
- Internal DNS resolution
level: high

---
title: 'CDB-Sentinel: The Notepad supply chain attack  unnoticed execution chains
  and new IoCs - File Indicators'
id: cdb-247872
status: experimental
description: 'Detects malicious file indicators associated with: The Notepad supply
  chain attack  unnoticed execution chains and new IoCs.'
author: CyberDudeBivash GOC (Automated)
date: 2026/02/17
tags:
- attack.execution
- attack.defense_evasion
logsource:
  category: file_event
  product: windows
detection:
  selection_file:
    TargetFilename|endswith:
    - 1.dll
    - AutoUpdater.exe
    - BluetoothService.exe
    - GUP.exe
    - ProShow.exe
  condition: selection_file
falsepositives:
- Legitimate software with matching names
level: high

---
title: 'CDB-Sentinel: The Notepad supply chain attack  unnoticed execution chains
  and new IoCs - Behavioral Detection'
id: cdb-833487
status: experimental
description: 'Behavioral detection for TTPs associated with: The Notepad supply chain
  attack  unnoticed execution chains and new IoCs. Detects suspicious process execution
  patterns.'
author: CyberDudeBivash GOC (Automated)
date: 2026/02/17
tags:
- attack.execution
- attack.persistence
logsource:
  category: process_creation
  product: windows
detection:
  selection:
    Image|endswith:
    - powershell.exe
    - cmd.exe
    - mshta.exe
    - wmic.exe
    CommandLine|contains:
    - -enc
    - -nop
    - -w hidden
    - bypass
    - downloadstring
    - invoke-
    - iex(
  condition: selection
falsepositives:
- Legitimate administrative scripts
- Software deployment tools
level: medium

6.2 YARA Rules

Deploy this YARA rule for memory and disk forensics scanning across endpoints. Compatible with YARA-enabled EDR solutions and standalone YARA scanning.

rule CDB_The_Notepad___supply_chain_attack___unno {
    meta:
        author = "CyberDudeBivash GOC"
        description = "Detects indicators associated with: The Notepad++ supply chain attack — unnoticed execution chai"
        date = "2026-02-17"
        reference = "https://cyberbivash.blogspot.com"
        severity = "high"
        tlp = "TLP:CLEAR"

    strings:
        $ip0 = "138.0.0.0" ascii wide
        $ip1 = "140.0.0.0" ascii wide
        $dom2 = "1.txt" ascii wide nocase
        $dom3 = "a.txt" ascii wide nocase
        $dom4 = "alien.ini" ascii wide nocase
        $dom5 = "api.skycloudcenter" ascii wide nocase
        $dom6 = "api.wiresguard" ascii wide nocase
        $file7 = "1.dll" ascii wide nocase
        $file8 = "AutoUpdater.exe" ascii wide nocase
        $file9 = "BluetoothService.exe" ascii wide nocase
        $url10 = "https://api.skycloudcenter[." ascii wide
        $url11 = "https://api.wiresguard[." ascii wide
        $url12 = "https://cdncheck.it[." ascii wide
        $beh13 = "cmd.exe /c" ascii wide nocase
        $beh14 = "whoami" ascii wide
        $beh15 = "net user" ascii wide nocase

    condition:
        uint16(0) == 0x5A4D and filesize < 10MB and 3 of them
}

6.3 SIEM Queries

Microsoft Sentinel (KQL):

// CDB-Sentinel: The Notepad++ supply chain attack — unnoticed execution chai
let CDB_IOCs = dynamic(["1.txt", "a.txt", "alien.ini", "api.skycloudcenter", "api.wiresguard", "api.wiresguard.com", "cdncheck.it", "cdncheck.it.com", "if.dnt", "ns.tmp"]);
union DeviceNetworkEvents, DnsEvents, CommonSecurityLog
| where RemoteUrl has_any (CDB_IOCs)
   or DestinationIP has_any (CDB_IOCs)
   or Name has_any (CDB_IOCs)
| project TimeGenerated, DeviceName, RemoteUrl, DestinationIP, ActionType
| sort by TimeGenerated desc

Splunk SPL:

| index=* sourcetype=firewall OR sourcetype=dns
| search dest="138.0.0.0" OR dest="140.0.0.0" OR dest="1.txt" OR dest="a.txt" OR dest="alien.ini" OR dest="api.skycloudcenter" OR dest="api.wiresguard" OR dest="api.wiresguard.com"
| table _time src dest action bytes_out
| sort -_time

6.4 Network Detection

Monitor network traffic for connections to identified infrastructure. Implement the following Suricata/Snort compatible rule for network-level detection:

alert dns any any -> any any (msg:"CDB-Sentinel: 1.txt"; dns.query; content:"1.txt"; nocase; sid:9001; rev:1;)
alert dns any any -> any any (msg:"CDB-Sentinel: a.txt"; dns.query; content:"a.txt"; nocase; sid:9002; rev:1;)
alert dns any any -> any any (msg:"CDB-Sentinel: alien.ini"; dns.query; content:"alien.ini"; nocase; sid:9003; rev:1;)

7. VULNERABILITY & EXPLOIT ANALYSIS

No specific CVE identifiers were associated with this advisory at the time of publication. However, organizations should maintain awareness that threat actors frequently exploit recently disclosed vulnerabilities as part of malware campaign / threat actor operation operations. Continuous vulnerability scanning and risk-based patch prioritization remain critical defensive requirements regardless of whether specific CVEs are referenced in individual advisories.

8. RISK SCORING METHODOLOGY

The CyberDudeBivash Sentinel APEX Risk Engine calculates threat risk scores using a weighted multi-factor analysis model. This transparent methodology ensures that all risk assessments are reproducible, defensible, and aligned with enterprise risk management frameworks. The scoring formula considers the following dimensions:

This scoring methodology provides full transparency into how risk assessments are calculated, enabling security teams to validate findings and adjust organizational response priorities based on their specific risk appetite and threat exposure profile.

9. 24-HOUR INCIDENT RESPONSE PLAN

Organizations that identify exposure to this threat should execute the following immediate containment actions within the first 24 hours of detection:

• Network Segmentation: Isolate affected network segments to prevent lateral movement. Implement emergency firewall rules blocking all identified IOCs at perimeter and internal boundaries.
• IOC Blocking: Deploy all indicators from Section 4 to firewalls, web proxies, DNS filters, and endpoint protection platforms immediately. Prioritize IP and domain blocking.
• Credential Resets: Force password resets for any accounts that may have been exposed. Revoke active sessions and API tokens for compromised or potentially compromised accounts.
• Endpoint Scanning: Execute full disk and memory scans using updated YARA rules (Section 6.2) across all endpoints in the affected environment. Prioritize servers and privileged workstations.
• Forensic Capture: Preserve evidence by capturing memory dumps, disk images, and network packet captures from affected systems before any remediation actions that could alter evidence.
• Threat Hunting: Conduct proactive hunting using the SIEM queries from Section 6.3 to identify any historical compromise that predates detection.

10. 7-DAY REMEDIATION STRATEGY

Following initial containment, execute this structured remediation plan over the subsequent 7 days to ensure comprehensive threat elimination and hardening:

• Day 1-2 — MFA Enforcement: Deploy FIDO2-compliant multi-factor authentication across all external-facing and privileged accounts. Disable legacy authentication protocols (NTLM, Basic Auth).
• Day 2-3 — Patch Deployment: Accelerate patching for all vulnerabilities referenced in this advisory. Prioritize internet-facing systems and those with known exploit availability.
• Day 3-5 — Access Policy Hardening: Review and tighten conditional access policies. Implement Just-In-Time (JIT) access for administrative functions. Audit service accounts.
• Day 5-6 — Threat Hunting Sweep: Conduct comprehensive threat hunting across the enterprise using behavioral indicators from the MITRE ATT&CK mappings in Section 5.
• Day 6-7 — Log Retention Review: Ensure logging coverage meets forensic investigation requirements (minimum 90-day retention). Verify SIEM ingestion of all critical data sources.

11. STRATEGIC RECOMMENDATIONS

Beyond immediate incident response, organizations should evaluate the following strategic security improvements to reduce exposure to similar future threats:

• Zero Trust Architecture: Transition from perimeter-based security to a Zero Trust model that verifies every access request regardless of source location. Implement micro-segmentation.
• Behavioral Detection: Supplement signature-based detection with behavioral analytics capable of identifying novel attack techniques and living-off-the-land attacks.
• Threat Intelligence Integration: Subscribe to curated threat intelligence feeds and integrate automated IOC ingestion into SIEM/SOAR platforms for real-time protection.
• Security Awareness: Conduct targeted phishing simulation exercises for employees. Implement continuous security awareness training with measurable effectiveness metrics.
• SOC Automation: Deploy SOAR playbooks for automated triage and response to common threat scenarios. Reduce mean time to detect (MTTD) and respond (MTTR).
• Supply Chain Security: Implement vendor risk assessment frameworks and continuous monitoring of third-party software dependencies for emerging vulnerabilities.

12. INDUSTRY-SPECIFIC GUIDANCE

Different industries face unique risk profiles from this threat. The following targeted guidance addresses sector-specific considerations:

Financial Services

Ensure PCI-DSS compliance requirements are met for all systems in scope. Implement transaction monitoring for anomalous patterns. Review and strengthen API security for digital banking platforms. Coordinate with FS-ISAC for sector-specific intelligence sharing.

Healthcare

Verify HIPAA-compliant security controls around electronic health records (EHR) systems. Isolate medical device networks from general IT infrastructure. Ensure backup systems are operational and tested for ransomware scenarios.

Government

Align response with CISA directives and BOD requirements. Review FedRAMP authorized service configurations. Coordinate with sector-specific ISACs. Implement enhanced monitoring on .gov and .mil domains.

Technology / SaaS

Review CI/CD pipeline security. Audit third-party dependencies for vulnerability exposure. Implement enhanced monitoring on customer-facing APIs. Review incident communication plans for customer notification.

Manufacturing / Critical Infrastructure

Isolate OT/ICS networks from IT infrastructure. Review remote access policies for industrial control systems. Implement enhanced monitoring at IT/OT boundaries.

Education

Review student and faculty data protection controls. Monitor for credential-based attacks against identity providers. Ensure research data repositories are adequately segmented.

13. GLOBAL THREAT TRENDS CONNECTION

This advisory connects to several dominant trends in the 2025-2026 global threat landscape. Threat actors continue to evolve their operations with increasing sophistication, leveraging AI-assisted attack tooling, targeting identity infrastructure, and exploiting the growing complexity of hybrid cloud environments.

Key trend connections include: the continued rise of infostealer malware ecosystems that fuel initial access broker markets; the weaponization of legitimate cloud services for command and control infrastructure; the acceleration of vulnerability exploitation timelines (often within hours of public disclosure); and the increasing professionalization of cybercrime operations including ransomware-as-a-service (RaaS) and access-as-a-service (AaaS) models.

Organizations that invest in behavioral detection capabilities, continuous threat intelligence integration, and security automation will be best positioned to defend against the evolving threat landscape. The shift from reactive, signature-based defense to proactive, intelligence-driven security operations represents the most impactful strategic investment available to security leaders.

14. CYBERDUDEBIVASH AUTHORITY SECTION

15. INTELLIGENCE KEYWORDS & TAXONOMY

16. APPENDIX

Source Reference: https://securelist.com/notepad-supply-chain-attack/118708/

STIX 2.1 Bundle: Available via the CyberDudeBivash Threat Intel Platform JSON feed.

IOC Format: Structured JSON export available for SIEM/SOAR integration.

Report Version: v15.0 | Generated by Sentinel APEX AI Engine

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This advisory is produced by the CyberDudeBivash Pvt. Ltd. Global Operations Center. Intelligence correlation, risk scoring, and detection engineering are powered by the Sentinel APEX AI Engine.

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© 2026 CyberDudeBivash Pvt. Ltd. // CDB-GOC-01 // Bhubaneswar, India