Case Study: Mjolnir Security’s Intervention in a Ransomware Attack on an ISP

Case Study + Ransomware Mjolnir Security todayJuly 5, 2024 10

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In late 2023, a prominent Internet Service Provider (ISP) experienced a severe ransomware attack that threatened its operations, financial stability, and reputation. The attack’s origin was traced back to the ISP’s Managed Service Provider (MSP), which had neglected essential security and auditing controls. Despite these deficiencies, the MSP attempted to shift the blame to the ISP, offering no logs or evidence to substantiate their claims. The ISP, seeking clarity and resolution, enlisted the expertise of Mjolnir Security.

Mjolnir Security deployed a comprehensive strategy encompassing forensic analysis, network monitoring, threat hunting, incident response, crisis communication, and litigation support. The investigation revealed that threat actors had established a virtual machine (VM) within the MSP’s network, using it as a launchpad for the ransomware attack on the ISP. This case study details how Mjolnir Security’s multifaceted approach not only helped the ISP recover from the attack but also held the MSP accountable for its security failures.


The client, a leading ISP, plays a crucial role in providing internet services to thousands of customers, including businesses and individuals. The ISP relies on an MSP to manage and secure its IT infrastructure, expecting robust security measures and diligent auditing controls to protect against cyber threats. However, in late 2023, the ISP faced an unexpected and devastating ransomware attack that disrupted its operations, causing significant financial losses and customer dissatisfaction.

The ISP’s MSP, responsible for ensuring security, failed to provide adequate protections, leading to the compromise. Despite this, the MSP attempted to deflect blame onto the ISP, claiming without evidence that the breach was due to the ISP’s security lapses. This lack of accountability and transparency prompted the ISP to seek external expertise from Mjolnir Security to uncover the truth and mitigate the damage.

Forensic Analysis

Mjolnir Security initiated the forensic analysis by conducting a comprehensive review of the ISP’s network and systems to identify the attack vector and understand the full scope of the breach. This process involved several key steps:

Log Analysis

Mjolnir’s digital forensics team meticulously examined available logs, including network traffic, system logs, and endpoint security logs. The aim was to identify any anomalies or indicators of compromise (IOCs) that could pinpoint the origin and timeline of the attack. The analysis revealed unusual traffic patterns and unauthorized access attempts that aligned with the time frame of the ransomware deployment.

System Imaging and Analysis

Key systems and servers were imaged to preserve their state for detailed analysis. Mjolnir’s experts scrutinized system files, registry entries, and memory dumps to trace the actions of the threat actors. This examination uncovered evidence of malware installation and execution, confirming the presence of malicious activities leading to the ransomware deployment.

Virtual Machine Identification

One critical discovery was the identification of virtual machines (VMs) set up within the MSP’s network. Threat actors often use VMs to bypass security controls and maintain persistence in compromised environments. These VMs were used as a staging ground for launching the ransomware attack against the ISP. The analysis showed that the VMs were configured and controlled from within the MSP’s infrastructure, implicating them in the security breach.

Evidence Preservation

To ensure the integrity of the investigation, Mjolnir Security preserved all relevant evidence, including logs, system images, and network traffic captures. This documentation was crucial for both understanding the attack and supporting the ISP’s claims against the MSP.

Network Monitoring, Threat Hunting via Mjolnir’s SOC

Mjolnir Security’s Security Operations Center (SOC) played a pivotal role in monitoring the ISP’s network and hunting for threats. This involved continuous surveillance, advanced threat intelligence, and proactive measures to identify and neutralize threats.

Behavioral Analysis

Using sophisticated threat intelligence tools, Mjolnir’s SOC performed behavioral analysis to detect unusual patterns and activities within the ISP’s network. This included monitoring for unauthorized access, data exfiltration attempts, and lateral movement by the threat actors. The SOC identified several suspicious activities that indicated ongoing malicious efforts to compromise the ISP’s systems.

Threat Hunting

Mjolnir’s threat hunters actively searched for hidden threats within the ISP’s environment. This involved deep dives into network traffic, endpoint activities, and system behaviors to uncover any remnants of the attackers’ presence. The team discovered that the threat actors had established covert channels for communication and control, further confirming the MSP’s involvement in the breach.

Virtual Machine Detection

One of the significant findings was the detection of VMs within the MSP’s network. These VMs were used to bypass security controls and execute the ransomware attack on the ISP. Mjolnir’s SOC traced the setup and usage of these VMs, providing critical evidence of the MSP’s security lapses and the attackers’ methods.

Continuous Monitoring

To prevent further incidents, Mjolnir’s SOC implemented continuous monitoring of the ISP’s network. This involved real-time threat detection, incident response, and regular security assessments to ensure that any potential threats were promptly identified and mitigated.

Incident Response Recovery via Mjolnir Shield

Mjolnir Security’s incident response team, leveraging the Mjolnir Shield service, executed a comprehensive recovery plan to restore the ISP’s operations and secure its environment.

Containment and Eradication

Immediate steps were taken to contain the threat and prevent the spread of ransomware. This involved isolating infected systems, disabling compromised accounts, and implementing network segmentation to limit the attackers’ movement. Mjolnir’s team worked closely with the ISP’s IT staff to ensure that all potential entry points were secured.

System Restoration and Decryption

Mjolnir Security assisted the ISP in restoring systems from clean backups, ensuring minimal data loss and downtime. The team also provided support in decrypting affected files, leveraging available tools and expertise to recover critical data. This process included validating the integrity of restored systems to prevent re-infection.

Patch Management and Vulnerability Mitigation

To close any vulnerabilities exploited during the attack, Mjolnir Security conducted a thorough patch management and vulnerability mitigation process. This involved updating systems, applying security patches, and implementing additional safeguards to fortify the ISP’s defenses against future attacks.

Post-Incident Review and Reporting

A detailed post-incident review was conducted to analyze the attack and the response efforts. This review provided valuable insights into the attackers’ methods, the MSP’s security failures, and the effectiveness of the recovery measures. A comprehensive report was prepared, documenting the findings and recommending further improvements to the ISP’s security posture.

Crisis Communication

Effective communication was crucial to managing the crisis and maintaining the ISP’s reputation. Mjolnir Security assisted the ISP in developing and executing a crisis communication plan.

Internal Communication

Clear and timely communication with internal stakeholders, including employees and management, was essential to ensure coordinated efforts during the recovery process. Mjolnir helped draft internal memos and updates to keep everyone informed about the progress and measures being taken.

Customer Communication

To address customer concerns and maintain trust, Mjolnir Security assisted the ISP in crafting transparent and reassuring messages. These communications explained the situation, the steps being taken to resolve it, and the measures implemented to prevent future incidents. Regular updates were provided to keep customers informed and alleviate their concerns.

Media and Public Relations

Mjolnir Security supported the ISP in handling media inquiries and managing public relations. This involved preparing press releases, coordinating with media outlets, and ensuring consistent messaging to the public. The focus was on transparency, accountability, and demonstrating the ISP’s commitment to resolving the issue and enhancing security.

Litigation Support to Sue the MSP for Damages

Given the MSP’s failure to provide adequate security and the resulting damages, the ISP sought legal recourse. Mjolnir Security provided critical support in the litigation process.

Evidence Collection and Documentation

Mjolnir Security meticulously documented all findings, including logs, system images, and forensic analysis results. This evidence was crucial in building a strong case against the MSP, demonstrating their negligence and the direct impact on the ISP.

Expert Testimony

Mjolnir’s experts provided testimony to support the ISP’s claims, explaining the technical aspects of the attack and the MSP’s security lapses. Their expertise added credibility to the ISP’s case and helped the legal team understand the complexities of the incident.

Legal Coordination

Mjolnir Security coordinated with the ISP’s legal team to ensure that all technical evidence and expert insights were effectively utilized in the litigation process. This collaboration aimed to maximize the chances of a successful outcome for the ISP.


The ransomware attack on the ISP highlighted the critical importance of robust security practices and accountability among service providers. Mjolnir Security’s comprehensive approach, encompassing forensic analysis, network monitoring, incident response, crisis communication, and litigation support, was instrumental in helping the ISP recover from the attack and hold the MSP accountable for its failures.

Mjolnir’s intervention not only restored the ISP’s operations but also enhanced its security posture, ensuring better protection against future threats. This case study underscores the value of expertise, transparency, and proactive measures in managing and mitigating cyber incidents.

Written by: Mjolnir Security

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