The SolarWinds hack was one of the most sophisticated supply chain cyberattacks in recent history, leveraging stealth, trust exploitation, and advanced evasion techniques. Traditional security mechanisms were insufficient to detect or mitigate the attack, which compromised thousands of organizations worldwide. This whitepaper presents a new conceptual security system named CASAMIR, conceptually based on the record-and-replay technology pioneered by REnigma, and extends it into a real-time security framework that could potentially address such threats. CASAMIR integrates a differential rules engine that dynamically approves or vetoes system actions based on predefined behavioral models, gating access to the outside world and offering new layers of protection against advanced persistent threats (APTs). Using the SolarWinds attack as a case study, this paper explores the potential effectiveness of CASAMIR, as well as its limitations and the key challenges it must overcome to be practical for deployment.

Introduction

Cyberattacks are growing in complexity, with threat actors often bypassing traditional security mechanisms by blending into legitimate software processes. One prominent example is the SolarWinds hack—a sophisticated supply chain attack that compromised SolarWinds’ Orion software, allowing attackers to insert malicious code that remained undetected for months. The attack demonstrated the weaknesses in traditional network monitoring, intrusion detection systems, and even post-incident forensics.

In response to such evolving threats, the CASAMIR system (Cyber Attack Supervision and Mitigation via Interception and Replay) is proposed as a new cybersecurity approach that extends the record-and-replay paradigm. CASAMIR introduces a differential rules engine that supervises the real-time execution of software systems, preventing unauthorized actions and offering a secondary layer of protection. This whitepaper outlines CASAMIR’s architecture, its application to the SolarWinds scenario, and its strengths and weaknesses as a solution for modern cyber defense.

The Foundation: REnigma’s Record-and-Replay Technology

REnigma, developed by Julian Grizzard and his team, is a cybersecurity technology that records every action performed on a system—system calls, process executions, memory access, and network activity. This detailed log can be replayed to recreate the exact system state at any given point in time, allowing for deep forensic analysis after a cyber incident. Key use cases include:

  • Post-incident analysis: Reconstructing the actions leading to a breach.
  • Zero-day exploit investigation: Understanding the exploitation of vulnerabilities in real-time.
  • Behavior analysis: Detecting previously unknown malware by replaying its actions.

While record-and-replay approach has proven invaluable in retrospective analysis, its utility in real-time prevention has been limited. CASAMIR builds on this foundation to address that gap by adding a dynamic security supervision layer.

CASAMIR Technology: Extension of Record-and-Replay for Real-Time Security

Innovations in CASAMIR

The CASAMIR system extends core recording capabilities by introducing a differential rules engine. This engine works in real time to analyze the stream of emissions—system calls, instructions, or other significant events—generated by the system as it runs. Instead of merely recording and storing these events for later analysis, the system actively approves or vetoes actions based on predefined security rules. The engine is essentially a supervisory control that gates an application’s ability to interact with external systems or resources.

Core Components:

  • Record Stream: Continuously captures the real-time actions of the system, leveraging detailed logging capabilities.
  • Differential Rules Engine: A mathematical model (based on differential equations or machine-learned behavioral profiles) that defines acceptable behavior for the system.
  • Veto/Approval Mechanism: Acts as a gatekeeper, intercepting and either allowing or blocking emissions from the system to ensure they comply with predefined rules.
  • Post-Mortem Replay: Maintains the traditional record-and-replay functionality for forensic analysis, allowing detailed investigation after an incident, even if the real-time system fails to block the attack.

Operation of the Differential Rules Engine

The differential rules engine works by comparing the live stream of actions against a set of predefined “acceptable” patterns. For example:

  • System call patterns: Certain applications should only make specific system calls under certain conditions (e.g., a web server accessing configuration files).
  • Network activity: Traffic should only be sent to authorized external destinations and within expected bandwidth limits.
  • Behavior sequences: Applications should follow predictable sequences of actions during their operation (e.g., file accesses followed by network requests).

The system continuously checks these behaviors in real time. Any deviation from expected behavior, such as accessing sensitive files at unusual times or sending unexpected network packets, triggers the veto mechanism, blocking the action before it can take effect.

The SolarWinds Hack: A Motivating Example

The SolarWinds hack leveraged the compromise of the SolarWinds Orion software, embedding malicious code into updates that were distributed to thousands of organizations. Once installed, the malware communicated with command-and-control (C2) servers, allowing attackers to extract data and move laterally across networks while remaining undetected for months. The attackers’ stealth and use of legitimate, signed software updates made detection extremely difficult.

CASAMIR’s Potential Performance in the SolarWinds Attack

How CASAMIR Could Have Mitigated the SolarWinds Attack

1. Real-Time C2 Communication Detection:

  • CASAMIR’s Function: By monitoring network emissions in real time, CASAMIR’s rules engine could have flagged the suspicious outbound traffic to unfamiliar C2 servers. This traffic would have appeared anomalous compared to typical SolarWinds Orion traffic patterns.
  • Outcome: The rules engine could have vetoed this communication, preventing the malware from contacting the attackers’ servers and receiving instructions.

2. Anomalous System Calls and Actions:

  • CASAMIR’s Function: The malware executed within the legitimate SolarWinds Orion process but performed actions outside of the expected behavior (e.g., unusual file accesses, privilege escalations). CASAMIR could have detected these deviations from expected system behavior.
  • Outcome: By vetoing these system calls, CASAMIR might have prevented the malware from accessing sensitive files or escalating privileges to move laterally.

3. Replay for Forensic Investigation:

  • CASAMIR’s Function: Even if the malware succeeded in bypassing the real-time veto mechanisms, CASAMIR’s detailed logging would have provided a full replay of the malware’s actions for post-incident investigation.
  • Outcome: Investigators would have been able to retrace the exact steps of the attackers, accelerating remediation and enabling further refinement of the rules engine to prevent future attacks.

Limitations and Challenges in Detecting SolarWinds

While CASAMIR presents a compelling defense mechanism, it also faces significant challenges in a scenario like SolarWinds:

  • 1. Trusted Execution and Stealth Tactics: The SolarWinds malware was inserted into a trusted, signed update. CASAMIR’s rules engine might have struggled to detect deviations in behavior if the malicious code closely mimicked normal SolarWinds process activity.
    • Outcome: If the differential rules weren’t specific enough to catch these subtle differences, CASAMIR might not have vetoed the malware’s actions until after significant damage was done.
  • 2. Dormancy Period: The malware remained dormant for weeks before initiating malicious actions, meaning CASAMIR would not have detected any anomalous behavior during this period.
    • Outcome: CASAMIR’s real-time analysis only works when actions are taking place, so the system would not have provided early warning during the malware’s dormant phase.
  • 3. Low and Slow Approach: The attackers employed a “low and slow” tactic, deliberately blending their activity into normal system behavior. This makes it difficult for any real-time system to detect anomalies without highly fine-tuned rules.
    • Outcome: Without careful tuning and detailed knowledge of system behavior, CASAMIR might have allowed certain malicious actions to proceed undetected.

Pros and Cons of CASAMIR Technology

Pros:

  • Real-Time Protection: CASAMIR introduces a layer of real-time security by vetoing unauthorized or suspicious emissions before they impact the system.
  • Post-Mortem Replay: The ability to replay attacks enables better post-incident investigation and quicker remediation.
  • Flexible Rules Engine: The differential rules engine can adapt to different environments and system behaviors, evolving over time based on detected threats.

Cons:

  • Performance Overhead: Analyzing every system call and emission in real time introduces computational overhead, which could slow down high-performance systems.
  • Rule Complexity: Defining accurate rules for complex systems is non-trivial. Overly broad rules may miss subtle attacks, while overly specific rules could generate false positives.
  • Stealthy Attacks: Sophisticated attacks like SolarWinds that mimic legitimate behavior within trusted software processes remain difficult to detect, even for CASAMIR.
  • Dormancy and Low Profile: CASAMIR is not effective against attacks that remain dormant for extended periods or operate at such a low profile that they blend into normal operations.

Conclusion

The CASAMIR system offers a promising extension of record-and-replay technology, adding real-time security capabilities to traditional post-incident forensic methods. In the context of advanced supply chain attacks like SolarWinds, CASAMIR could have been effective in mitigating certain aspects of the attack, such as blocking command-and-control communications or preventing privilege escalation. However, it faces significant challenges, including the complexity of defining accurate rules for trusted software, performance overhead, and the inherent difficulty of detecting stealthy, low-profile attacks.

In conclusion, CASAMIR represents a valuable tool in the cybersecurity arsenal, particularly for environments where granular control over system behavior is critical. However, its success would require careful tuning of its differential rules engine and the integration of complementary security measures to ensure a robust defense against sophisticated threats like SolarWinds.

Acknowledgments

This work builds upon the record-and-replay foundations established by Julian Grizzard and his team with REnigma, whose technology provided the foundation for CASAMIR’s conceptual design.