InfoSec Briefing - February 04, 2026

🚨 Critical Vulnerability Alert

We have a critical security alert. CVE-2025-40551, a remote code execution in SolarWinds Web Help Desk via untrusted data deserialization, has been added to the CISA Known Exploited Vulnerabilities catalog.

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Good morning. This is your security briefing for Tuesday, February 03, 2026, covering ten articles analyzed overnight. All attribution is by the article authors. All article analysis is automated.

Researchers Shakhzod Yuldoldhjaev, Mijin Jeon, Doowon Kim, Nick Nikiforakis, and Hyungjoon Koo published comprehensive decade-long research analyzing fifteen hundred nine APT dossiers from six hundred three unique threat groups operating between 2014 and 2023. The study revealed that the United States, India, and South Korea were most frequently targeted across one hundred fifty-four countries, with malicious documents and spear phishing remaining dominant initial access vectors, though zero-day exploitation has significantly declined since 2016.

According to reports from Matt Green and Velociraptor, and YARA rules developed by mgreen27, the LotusBlossom campaign compromised Notepad++ versions 8.8.2 through 8.8.9 to distribute the Chrysalis backdoor. The malware exploits Microsoft's Warbird Runtime Code Protection feature, embedding malicious payloads within the first 0x490 bytes of Microsoft-signed clipc.dll to execute shellcode while evading antivirus and EDR detection, with command and control infrastructure including api.skycloudcenter.com and api.wiresguard.com.

Researchers Jan-Luca Gruber and Frederik Reiter detailed the Warbird abuse technique, which exploits kernel-level decryption APIs to decrypt and execute shellcode in a single system call, bypassing traditional security monitoring of user-mode memory allocation. This technique has been recently observed in the Notepad++ payload deliveries targeting Windows systems.

ACYCRAFT reports an advanced threat actor conducting an infrastructure-less campaign targeting Taiwan's government and manufacturing sectors since 2024. The attackers use dead-drop resolvers and Microsoft Graph API for command and control laundering, exploit Active Directory Certificate Services ESC vulnerabilities for privilege escalation, and deploy GRAPHBROTLI, GRAPHRELOOK, and RCREMARK malware families while leveraging legitimate cloud services to evade detection.

Trend Micro identified Earth Kurma, an APT group active since November 2020, conducting stealthy data exfiltration campaigns across Southeast Asia including the Philippines, Vietnam, Thailand, Malaysia, Brunei, and Indonesia. The group employs sophisticated multi-stage infection chains with advanced rootkits such as KRNRAT and MORIYA, custom loaders, and memory-resident agents while abusing trusted platforms like Dropbox, OneDrive, and Cisco Webex for lateral movement and data exfiltration from government and telecommunication sectors.

Researcher Omer Amiad discovered the GatewayToHeaven vulnerability, designated CVE-2025-13292, in Google Cloud's Apigee platform. This critical tenant isolation failure allowed unauthorized cross-tenant access to logs and analytics data containing plaintext access tokens, enabling attackers to read and write sensitive data and potentially compromise authentication credentials across organizations using Apigee.

Security researcher clearbluejar, also identified as digicat on infosec.pub, demonstrated how Large Language Models can accelerate reverse engineering of vulnerabilities using CVE-2025-29824 as a case study. This critical use-after-free vulnerability in Windows' Common Log File System driver stems from a race condition where the FsContext2 structure is freed during active IRP processing, potentially enabling privilege escalation or remote code execution on Windows systems.

YARAHQ released a YARA Rule Skill for LLM agents that automates over sixty quality checks for YARA rules, covering logic, performance, and style validation. The tool helps cybersecurity analysts and threat hunters improve rule quality by identifying issues that could lead to false positives, false negatives, or performance degradation.

CodeXTF2 released an open-source reimplementation of Cobalt Strike's Beacon Object File loader to address debugging challenges in BOF development. The tool provides a one-to-one replica of Cobalt Strike's loader implementation, enabling developers to troubleshoot issues with COMDAT sections and other COFF file structures, while exposing internal mechanics that may benefit both offensive tool developers and security researchers analyzing post-exploitation frameworks.

That concludes today's briefing.

📰 Articles Covered

A Decade-long Landscape of Advanced Persistent Threats: Longitudinal Analysis and Global Trends - v2 published January 6th - The content posted at the URL is copyrighted by the authors: **Shakhzod Yuldoldhjaev**, **Mijin Jeon**, **Doowon Kim**, **Nick Nikiforakis**, and **Hyungjoon Koo**.

This cybersecurity article provides a comprehensive decade-long analysis of Advanced Persistent Threats (APTs) from 2014 to 2023, based on 1,509 APT dossiers and identifying 603 unique APT groups.

**What Happened:**
The study tracked the activities of APT groups over ten years, observing global trends in their operations. It noted a significant decline in the exploitation of zero-day vulnerabilities since 2016.

**Who is Affected:**
A total of **154 countries** have been impacted by APT activities. The **United States, India, and South Korea** are the most frequently targeted nations. The primary sectors affected are **government and corporate entities**.

**Security Implications:**
APTs pose severe security risks due to their covert and long-term nature. Often orchestrated by state-sponsored actors, their objectives include **stealing sensitive data, disrupting critical operations, and undermining national security or economic stability**.

**Technical Details:**
The analysis encompassed **2,582 MITRE ATT&CK techniques** and **1,088 Common Vulnerabilities and Exposures (CVEs)**. The vulnerabilities identified had an average severity score of 8.5 and predominantly targeted **Windows and Office** platforms. **Malicious documents and spear phishing** were identified as the dominant initial infiltration vectors. Approximately half of the exploited vulnerabilities were zero-days, and APT campaign durations ranged from a single day to nearly five years.

**What Defenders Should Know:**
Defenders need to be aware of the **evolving tactics of APTs**, their persistent focus on key sectors and countries, and the observed shift away from zero-day exploitation. It is also crucial to recognize the correlation between cyberattacks and geopolitical events such as elections or wars. The research emphasizes the importance of **continuous monitoring, understanding historical threat patterns, and adapting defenses** to counter sophisticated, long-term threats. The authors also offer interactive visualization tools to help understand these global patterns 【1】.
Velociraptor artifact to assist scoping IOCs related to the recent publicly disclosed Notepad++ supply chain attack. - The content posted at the URL is controlled by **Matt Green** and the organization **Velociraptor**.

The cybersecurity article details a supply chain attack attributed to the **LotusBlossom campaign**, which compromised **Notepad++** installations to distribute a backdoor named **Chrysalis** 【1】.

**What Happened:**
The attack involved distributing a backdoor through compromised versions of the Notepad++ software. This backdoor, Chrysalis, was designed to execute shellcode, load malicious DLLs, and gather system information 【1】.

**Who is Affected:**
**Users of Notepad++ versions 8.8.2 through 8.8.9** are potentially affected by this attack 【1】.

**Security Implications:**
The primary security implication is the **deployment of a backdoor and loader** on affected systems. This allows attackers to gain a foothold, execute further malicious code, and conduct reconnaissance on the compromised environment 【1】.

**Technical Details:**
The article provides several technical indicators of compromise (IOCs):
- **File Paths:** Suspicious files may be found in directories such as `AppData\Roaming\Bluetooth`, `AppData\Roaming\ProShow`, `AppData\Adobe\Scripts`, `AppData\Local\Temp`, and `ProgramData\USOShared` 【1】.
- **Network IOCs:** Attackers used domains like `api.skycloudcenter.com` and `api.wiresguard.com`, along with specific IPs and ports. The malware also utilizes particular API paths 【1】.
- **Detection:** The article mentions YARA rules for detecting network indicators and Warbird clipc.dll artifacts 【1】.

**What Defenders Should Know:**
Defenders should be aware of the outlined IOCs to effectively identify and mitigate the threat. This includes:
- Utilizing the provided **detection artifact** to scan for impacted systems 【1】.
- Searching for **suspicious files** in the mentioned locations 【1】.
- Monitoring for **malicious network activity** originating from running processes and memory 【1】.
Infrastructure-less Adversary: C2 Laundering via Dead-Drop Resolvers and the Microsoft Graph API - ACYCRAFT

This cybersecurity article details an advanced threat actor employing "infrastructure-less" techniques, specifically using "dead-drop resolvers" and the Microsoft Graph API for Command and Control (C2) laundering. The campaign has been active since 2024 and primarily targets Taiwan's government and manufacturing sectors.

**What Happened:**
The attack chain begins with a **phishing campaign** to gain initial access. Subsequently, the adversaries exploit misconfigurations in **Active Directory Certificate Services (AD CS)**, specifically ESC vulnerabilities, to escalate privileges. They then use compromised high-privilege accounts for **lateral movement** via SMB. For C2 communication, they utilize legitimate cloud services and compromised websites, making their infrastructure difficult to trace and block. The malware families involved include **GRAPHBROTLI, GRAPHRELOOK, and RCREMARK**.

**Who is Affected:**
The primary targets of this campaign are **government entities and manufacturing industries within Taiwan**. The observed activity dates back to 2024.

**Security Implications:**
The use of infrastructure-less C2 methods presents a significant challenge for defenders. By leveraging legitimate services and compromised infrastructure, the attackers avoid using easily blockable malicious IPs or domains. This allows for **stealthy persistence and data exfiltration**, as malicious activities can blend in with normal network traffic. The attackers also employ **ephemeral modification of logon scripts** and utilize legitimate services like Microsoft Graph API, which complicates detection and attribution efforts.

**Technical Details:**
* **Malware:**
* **GRAPHBROTLI:** Uses Microsoft Graph API for C2 and employs a unique decoding method combining Brotli and base91.
* **GRAPHRELOOK:** Also utilizes Microsoft Graph API, specifically the Outlook API, for receiving C2 commands.
* **RCREMARK:** Employs Base64 and RC4 for decoding and communicates via C2 infrastructure protected by Cloudflare, retrieving commands from HTML responses using a specific regex pattern.
* **C2 Methods:**
* **Type 1 (Cloud Service):** Exploits legitimate cloud services such as Microsoft Graph API and Google Sheets.
* **Type 2 (C2 behind Cloudflare):** Hides C2 infrastructure behind Cloudflare to evade detection and blocking.
* **Type 3 (Compromised Website):** Leverages compromised legacy websites to host malicious payloads.
* **Attack Techniques:**
* **Ephemeral Modification:** Attackers temporarily alter legitimate scripts like "gpupdate.bat" (AD Logon Script) and "log.js" to execute malicious code, then revert them to their original state to evade detection.
* **AD CS Escalation (ESC):** Exploits misconfigurations in AD CS to gain Domain Admin privileges.
* **DLL Side-loading:** A technique used by the malware for payload execution.
* **Dead-Drop Resolvers:** A method where legitimate services or compromised sites act as intermediaries for C2 communication.

**What Defenders Should Know:**
* **Harden AD Logon Scripts:** Implement strict Access Control Lists (ACLs) on shared folders like SYSVOL/Netlogon to prevent unauthorized modifications to logon scripts.
* **Network Defense Strategies:**
* **Public Service Abuse:** Enforce strict whitelisting for critical assets and high-value targets.
* **SSL/TLS Inspection:** Decrypt and inspect encrypted traffic to identify hidden malicious payloads.
* **Compromised Infrastructure & CDNs:** Regularly update Threat Intelligence feeds with Indicators of Compromise (IOCs) and block newly registered domains (NRDs) to mitigate the use of disposable C2 infrastructure.
* **Behavioral Monitoring:** Monitor for non-browser processes that attempt to download executable files (EXE/DLL) from the internet.
* **Detection Challenges:** Defenders must recognize that traditional indicators like malicious IPs or domains may be absent. The focus should shift to detecting anomalous behavior within legitimate services and monitoring for script modifications and unusual network traffic patterns.
Ghost in Your Network: How Earth Kurma Stays Hidden and Exfiltrates Your Data - Trend Micro

The cybersecurity article details the activities of the APT group **Earth Kurma**, which has been actively engaged in stealthy data exfiltration since November 2020. The group primarily targets **government and telecommunication sectors** in Southeast Asian countries, including the Philippines, Vietnam, Brunei, Malaysia, Thailand, and Indonesia.

**What Happened:**
Earth Kurma initiates its attacks by compromising vulnerable web servers. Following this initial access, they deploy a multi-stage infection chain that utilizes various tools for lateral movement, establishing persistence, and exfiltrating data. Their operations are characterized by advanced techniques designed to evade detection, such as using memory-resident agents, abusing trusted platforms, and employing sophisticated rootkits.

**Who is Affected:**
The primary targets of Earth Kurma are organizations within the **government and telecommunication industries** located in Southeast Asia.

**Security Implications:**
The main security implication is the **exfiltration of sensitive data**, which is facilitated by Earth Kurma's advanced methods for remaining undetected. Their sophisticated defense evasion tactics make them difficult to identify and neutralize, posing a substantial risk to the targeted entities. The group's adaptability and their ability to leverage native system mechanisms and trusted platforms like DFSR, Dropbox, OneDrive, and Cisco Webex further complicate defense strategies.

**Technical Details:**
* **Initial Access:** Achieved through the exploitation of web server vulnerabilities.
* **Lateral Movement:** The group employs tools such as NBTSCAN, LADON, WMIHACKER, FRPC, ICMPINGER, and KMLOG to move within compromised networks.
* **Persistence:** Earth Kurma maintains persistence through various rootkits and loaders, including KRNRAT, MORIYA, MMLOAD, TESDAT, DUNLOADER, DMLOADER, and DOWNBEGIN. KRNRAT is a comprehensive backdoor capable of process manipulation, file and connection hiding, and shellcode injection. MORIYA functions as a traffic interceptor, while MMLOAD is a multi-stage backdoor that emerged in April 2024. DOWNBEGIN is a newer backdoor with reverse shell and file manipulation capabilities, existing in both Raw TCP and Cisco Webex variants.
* **Data Exfiltration:** Tools like ODRIZ, PowerShell, SIMPOBOXSPY, and SIMPOWEBEXSPY are used for exfiltration. Data is often sent through legitimate cloud services such as Dropbox, OneDrive, and Cisco Webex, or via DFSR. PowerShell is utilized to gather and archive files, which are then compressed using WinRAR before being transferred over SMB.
* **Command and Control (C&C):** Communication channels can involve TCP hijacking or Cisco Webex, with dedicated meeting rooms used for different communication types (messages, files, shells).
* **Attribution:** While not definitively attributed, Earth Kurma has weak links to other APT groups and shares common infrastructure providers, including XNNET LLC, Kaopu Cloud HK Limited, Vultr Holdings, LLC, Lightnode Limited, and Charter Communications Inc.

**What Defenders Should Know:**
Defenders need to be aware of Earth Kurma's continuously evolving toolset and their capacity to adapt to victim environments. Key defensive measures include:
* **Monitoring** for connections to legitimate cloud services initiated by unauthorized applications.
* Analyzing **anomalous intranet connections** that exhibit high traffic volumes.
* Implementing **group policies** to prevent the installation of untrusted drivers.
* Understanding the specific **Tactics, Techniques, and Procedures (TTPs)**, malware families (such as KRNRAT, MORIYA, MMLOAD, and DOWNBEGIN), and exfiltration methods employed by Earth Kurma.
Yara: "Detects payload bytes in first 0x490 bytes in clipc.dll Warbird technique as described by Rapid7 - The content posted at the URL is controlled by **mgreen27**.

The provided cybersecurity article is a YARA rule designed to detect a specific malware component.

- **What happened:** The YARA rule, named `APT_LotusBlossom_Chrysalis_Loader_Warbird`, is intended to detect the "Warbird" technique used by the Chrysalis malware, associated with the APT Lotus Blossom threat actor. This technique involves embedding payload bytes within the first 0x490 bytes of a Microsoft-signed DLL, specifically `clipc.dll`, within its VAD section.

- **Who is affected:** The rule targets systems where the `clipc.dll` file might be compromised or used to host malicious payloads. The threat actor "APT Lotus Blossom" suggests a focus on specific targets, likely in geopolitical or strategic sectors, though the article doesn't specify exact industries or regions.

- **Security implications:** The use of this technique implies that attackers are attempting to hide their malicious code within legitimate, signed DLLs, making detection more challenging. This can lead to persistent compromise, data exfiltration, and further network intrusion.

- **Technical details:** The YARA rule looks for specific hexadecimal byte sequences (`$hex1 = { EF BE AD DE }` and `$hex2 = { FE AF FE CA }`) within the first 1167 bytes (0x490) of the `clipc.dll` file. The rule is scoped to Microsoft-signed DLLs and specifically mentions the VAD section.

- **What defenders should know:** Defenders should be aware of this specific technique employed by APT Lotus Blossom and the Chrysalis malware. Implementing YARA rules like this one can help in detecting the presence of this malware. Monitoring for the specified byte sequences within `clipc.dll` and its VAD section is crucial. The reference provided in the rule points to a Rapid7 blog post for more in-depth analysis of the Chrysalis backdoor and Lotus Blossom's toolkit 【1】.
GatewayToHeaven: Finding a Cross-Tenant Vulnerability in GCP's Apigee - The content posted on the URL is controlled by **Omer Amiad** .

The **GatewayToHeaven** vulnerability, assigned **CVE-2025-13292**, was discovered in Google Cloud's Apigee platform. This vulnerability allowed unauthorized access to cross-tenant access logs and analytics data, including plaintext access tokens.

**What Happened:**
The vulnerability enabled an attacker to read and write sensitive data from Apigee's access logs and analytics. This data could include plaintext access tokens, which are crucial for authenticating users and services.

**Who is Affected:**
**Organizations using Google Cloud's Apigee** are potentially affected by this vulnerability. The compromise of access tokens could allow attackers to impersonate end-users of any organization utilizing Apigee.

**Security Implications:**
The primary security implication is the **risk of unauthorized access and impersonation**. By exfiltrating plaintext access tokens, attackers could gain access to user accounts and sensitive data, leading to potential data breaches and service disruptions.

**Technical Details:**
The vulnerability specifically targeted the cross-tenant access logs and analytics data within Apigee. The exact technical mechanism allowed for both reading and writing this data, indicating a significant flaw in how Apigee handled tenant isolation and data access controls. The presence of plaintext access tokens in these logs is a critical misconfiguration or design flaw.

**What Defenders Should Know:**
Defenders need to be aware of the potential for **compromised access tokens** and the implications for **tenant isolation** in cloud environments. It is crucial to ensure that all cloud services, especially API management platforms like Apigee, are configured securely and that access logs do not contain sensitive information in plaintext. Regular security audits and prompt patching of identified vulnerabilities are essential.
Abusing Microsoft Warbird for Shellcode Execution - from 2024 but recently utilised in the Notepad++ payloads - Jan-Luca Gruber and Frederik Reiter

A cybersecurity article details a method for **abusing Microsoft Warbird**, an internal code protection framework, to execute shellcode undetected by antivirus (AV) and Endpoint Detection and Response (EDR) solutions. This technique allows encrypted shellcode to be decrypted and loaded by the Windows kernel, bypassing security measures that typically scan for malicious code in user-mode memory or monitor memory allocation for execution.

**What Happened:**
The technique exploits the "Runtime Code Protection" feature of Microsoft Warbird. Originally, Warbird decrypted code in user mode. However, due to security measures like Arbitrary Code Guard (ACG) preventing user-mode processes from allocating executable memory, Microsoft shifted this functionality to the kernel. Attackers can now leverage this kernel-level API to have the Windows kernel decrypt shellcode, allocate executable memory for it, and then execute it, all within a single system call. This process ensures that the decrypted shellcode never resides in writable memory or is directly passed to user-space APIs that security software monitors.

**Who is Affected:**
This technique primarily affects **users of Windows operating systems** that utilize Microsoft Warbird, which was introduced in Windows 8/2012. Specifically, processes that are restricted from allocating executable memory, such as those protected by Arbitrary Code Guard (ACG), can be targeted. This includes legacy Microsoft Edge browser processes and potentially other sensitive applications.

**Security Implications:**
The primary security implication is the **evasion of detection by AV and EDR solutions**. Traditional security methods that rely on scanning memory for known malicious signatures or monitoring calls to functions like `VirtualProtect` to allocate and execute code are bypassed. Because the kernel handles the decryption and execution, and the decrypted shellcode is not exposed to user-space memory scans or typical shellcode-loading system calls, security software only observes encrypted code, rendering signature-based and heuristic detections ineffective. This technique has been successfully used in practice to bypass leading EDR solutions.

**Technical Details:**
- **Microsoft Warbird:** An undocumented internal framework for code protection and obfuscation, used for Digital Rights Management (DRM) and other sensitive code protection.
- **Kernel-Level Decryption:** Warbird's runtime decryption feature was moved to the kernel to overcome user-mode memory allocation restrictions.
- **Syscall for Execution:** The `NtQuerySystemInformation` syscall, with `SystemInformationClass` set to `SystemCodeFlowTransition` (0xB9), is used to invoke the Warbird functionality.
- **`WbOperationHeapExecuteCall`:** This specific operation type within the Warbird API is utilized for decrypting and allocating executable memory.
- **`HEAP_EXECUTE_CALL_ARGUMENT` Struct:** This structure contains parameters for the operation, including the encrypted code's offset (`ulRva`), size (`ulSize`), the decryption key (`ullKey`), and Feistel cipher round data. A `ucHash` field is used for integrity checking.
- **Bypassing Signature Checks:** To circumvent checks that require the `HEAP_EXECUTE_CALL_ARGUMENT` struct to be within a Microsoft-signed DLL's `.text` section, attackers load a legitimate signed DLL, use `VirtualProtect` to make its `.text` section writable, copy the struct and encrypted shellcode into it, and then set `ulRva` to point to the shellcode.
- **Encryption:** Shellcode is encrypted using a custom Feistel cipher provided by the leaked Warbird source code.
- **Limitations:** The maximum size for encrypted shellcode is 64 KiB (0x10000 bytes). The initial use of `VirtualProtect` to modify the signed DLL's `.text` section could potentially be detected, though the encrypted content mitigates this risk.

**What Defenders Should Know:**
Defenders need to be aware that traditional methods of detecting shellcode execution are insufficient against this technique. Strategies to counter this include:
- **Decrypting Shellcode:** Security products could attempt to decrypt shellcode passed to `NtQuerySystemInformation` and scan the decrypted content for signatures.
- **Blocking Warbird API Use:** Blocking the use of Warbird APIs in non-Microsoft processes.
- **Behavioral Detection:** Relying on behavioral analysis to identify suspicious process activities, even if the shellcode itself is not directly detected.
- **Periodic Memory Scanning:** Implementing periodic memory scans to detect decrypted shellcode that has been loaded into memory by the kernel.
- **Monitoring `VirtualProtect`:** While not foolproof, monitoring calls to `VirtualProtect` on sections of signed DLLs could be an indicator, especially if combined with other suspicious activities.
YARA Rule Skill [CRT] - An LLM Agent Skill that embeds expert YARA knowledge into your AI assistant. - YARAHQ controls the content posted at the URL .

The provided article details a **YARA Rule Skill** designed for Large Language Model (LLM) agents, rather than describing a specific cybersecurity incident.

Here's a precis based on the article's content:

- **What happened:** The article introduces and explains a new skill for LLM agents that allows them to review, optimize, and debug YARA rules. This skill automates over 60 quality checks for YARA rules.
- **Who is affected:** The skill is designed for users who work with YARA rules, such as cybersecurity analysts, threat hunters, and developers who use YARA for malware detection and threat intelligence. It is not related to a specific breach affecting end-users or organizations.
- **Security implications:** The primary security implication is the **improvement of YARA rule quality**. By identifying and rectifying issues related to logic, performance, and style, the skill helps reduce the risk of:
- Faulty rules negatively impacting scanning performance.
- False positives (flagging legitimate files as malicious).
- False negatives (failing to detect actual threats).
This leads to more effective and efficient threat detection.
- **Technical details:** The YARA Rule Skill offers more than 60 quality checks categorized into:
- **Logic checks:** Ensuring the rule's conditions are sound and intended.
- **Performance checks:** Optimizing rules for faster execution.
- **Style checks:** Adhering to best practices and conventions for readability and maintainability.
It can analyze rule usage, identify potential performance bottlenecks, and enforce coding standards. Installation can be done by cloning the GitHub repository or packaging it as a skill.
- **What defenders should know:** Defenders should be aware that this skill **enforces best practices for writing YARA rules**. This includes guidance on using anchors, efficient substring matching, and proper metadata conventions. It can be used to audit existing YARA rules or public rules before deployment to ensure they are robust, performant, and reliable for threat detection purposes.
Cobaltstrike_BOFLoader: open source port/reimplementation of the Cobalt Strike BOF Loader as is - CodeXTF2

The provided GitHub repository, **Cobaltstrike_BOFLoader**, is an open-source reimplementation of Cobalt Strike's Beacon Object File (BOF) loader. The primary purpose of this project is to serve as a debugging tool for BOF development, specifically addressing issues that arise when BOFs function correctly in other COFF loaders but not within Cobalt Strike's native loader.

**What Happened:**
The creator of the repository developed this tool due to persistent issues encountered with Cobalt Strike's native BOF loader, particularly concerning the handling of sections like COMDATs. These issues were not reproducible in other open-source COFF loaders, leading to frustration and a lack of debuggability. The Cobalt Strike loader also processes COFF files on the teamserver before sending a smaller, undocumented blob to the Beacon, further complicating development. This project aims to create a 1:1 replica of Cobalt Strike's implementation to ensure that any issues found in one are reproducible in the other.

**Who is Affected:**
This project primarily affects **developers working with Cobalt Strike's BOF framework**. It is particularly relevant for those who have experienced difficulties with Cobalt Strike's loader not handling certain COFF file structures correctly, leading to BOFs failing to execute as expected.

**Security Implications:**
While the repository itself is a tool for developers, its existence and functionality have security implications:

* **Enhanced BOF Development and Debugging:** By providing a more transparent and debuggable loader, it can potentially lead to more sophisticated and effective BOFs being developed.
* **Understanding Cobalt Strike Internals:** The project offers insights into the internal workings of Cobalt Strike's BOF loader, which could be valuable for both defenders and attackers seeking to understand and potentially exploit its mechanisms.
* **Potential for Evasion:** A better understanding of how BOFs are loaded could aid in developing techniques to evade detection by security solutions that monitor Cobalt Strike activity.

**Technical Details:**
The repository contains the source code for a BOF loader that aims to replicate Cobalt Strike's functionality. It includes:

* **Compilation Scripts:** `compile.bat` is provided for compiling the loader.
* **BOF Packing Script:** `bof_pack.py` is used to process a compiled BOF object file (e.g., `Msgbox.x64.o`) into a `.blob` format.
* **Loader Execution:** The compiled loader (`bofloader.exe`) can then execute the `.blob` file.
* **Focus on Replication:** The project intentionally replicates the shortcomings of the original Cobalt Strike loader, rather than improving upon them, to ensure accurate debugging and comparison.

**What Defenders Should Know:**
Defenders should be aware of this project for several reasons:

* **Understanding Attacker Tools:** This project provides a clearer view into how attackers might develop and deploy BOFs using Cobalt Strike.
* **Detection Opportunities:** By understanding the loading process and potential issues, defenders may be able to develop more targeted detection rules for anomalous BOF loading behavior or specific loader characteristics.
* **Threat Intelligence:** The existence of such open-source reimplementations can be a valuable piece of threat intelligence, indicating a community effort to better understand and utilize Cobalt Strike's capabilities.
* **Focus on Anomalous Behavior:** Since the loader aims to replicate Cobalt Strike's behavior, defenders should focus on detecting the execution of unknown or suspicious `.blob` files, or unusual process injection patterns associated with BOF execution.
How LLMs Feed Your RE Habit: Following the Use-After-Free Trail in CLFS - clearbluejar (author identified as digicat on infosec.pub)

This article details how Large Language Models (LLMs) can expedite the reverse engineering (RE) of cybersecurity vulnerabilities, using a **use-after-free (UAF)** flaw in Windows' **Common Log File System (CLFS)** driver (CVE-2025-29824) as a case study.

- **What Happened**: The vulnerability, identified as CVE-2025-29824, stems from a race condition within the CLFS driver. Specifically, the `FsContext2` structure is freed in the `CClfsRequest::Cleanup()` function while an I/O Request Packet (IRP) might still be actively processing. This creates a use-after-free scenario, where a freed memory location is accessed, potentially leading to system compromise. The vulnerability can be triggered through specific IOCTLs and handle closing operations.

- **Who is Affected**: The primary users affected are **Windows operating system users**, as the vulnerability resides in a core kernel-level driver. Attackers could exploit this to gain elevated privileges or execute arbitrary code on a compromised system.

- **Security Implications**: A UAF vulnerability in a critical kernel driver like CLFS carries severe security implications. These include:
- **System instability and crashes**: Improper memory management can lead to unpredictable behavior and denial-of-service conditions.
- **Privilege escalation**: Attackers could leverage the UAF to gain higher system privileges than they initially possessed.
- **Remote code execution**: In the worst-case scenario, an attacker might be able to execute malicious code remotely, taking full control of the affected system.

- **Technical Details**: The core technical detail is the **race condition** involving the `FsContext2` structure and an ongoing IRP. When `CClfsRequest::Cleanup()` frees `FsContext2`, if another IRP is still using it, a UAF occurs. This can be exploited by carefully timing I/O operations and handle closures. The article uses LLMs and the `pyghidra-mcp` tool to trace this vulnerability through a patch diff and understand its behavior within the CLFS driver.

- **What Defenders Should Know**: Defenders can benefit significantly from LLMs in several ways:
- **Accelerated Triage**: LLMs can rapidly analyze patch diffs and binary code to identify potentially vulnerable functions, significantly speeding up the initial assessment of threats.
- **Validation of Research**: AI can help validate external research findings against the actual binary, increasing confidence in discovered vulnerabilities.
- **Focus on Higher-Level Reasoning**: By automating much of the manual verification and tracing, analysts can dedicate more time to complex analysis and strategic defense planning.
- **Quantifiable Speedup**: The article suggests LLMs can lead to **up to a 90% time saving** in reverse engineering tasks, making the analysis process feel lighter and faster, and allowing for more thorough investigations.