How to Recover Data from a RAID 5 Server After a Ransomware Attack | Stellar Chennai Branch

Summary: A Phobos ransomware attack encrypted the data on an MEP consulting firm’s Linux-based RAID 5 server. The company was left without access to critical business information. Instead of paying the ransom, the firm approached Stellar Data Recovery. The recovery team cloned the affected drives, virtually rebuilt the RAID 5 array, and used proprietary tools to recover the encrypted data. This professional recovery process restored the data without reliance on the attackers.

A decade ago, ransomware was a term familiar mainly to IT departments and largely unknown elsewhere. That has changed. The threat has grown far more sophisticated over the years. New variants and strains continue to emerge, with small and medium-sized organisations frequently targeted. This is largely because they lack the resources and cybersecurity infrastructure available to larger enterprises. Every business leader now has reason to take this threat seriously, since failing to do so exposes an organisation to considerable operational and financial risk.

The scale of the problem is significant. A recent survey reported by The Hindu found that more than half of Indian enterprises faced a ransomware attack in the past year, including both large corporations and a growing number of small and mid-sized businesses.

An MEP consulting firm was among those affected. What follows is an account of how a Phobos ransomware attack encrypted data on its RAID 5 server, and how Stellar Data Recovery restored it through RAID data recovery.

An Overview of NAS Specifications

• Operating system: Linux
• RAID level: RAID 5
• Drive configuration: 3 × 4 TB HDDs
• RAID chunk/stripe size: 128 KB
• Filesystem type: ext4

The Challenge

The attack was traced to Phobos, a notorious cyber threat first identified in 2018. AES-256 encryption was used to lock down critical data on the firm’s Linux-based RAID 5 server. The encryption of a single server was sufficient to bring the entire firm’s operations to a standstill.

Contacting the attackers was never considered a viable option. Instead, the IT team approached the Stellar Data Recovery Chennai branch, a decision that would ultimately deliver far better results than any negotiation could have achieved.

The Ransomware Recovery Approach

Every case brings its own set of complications, and this one was no exception. Identifying the ransomware strain was the essential first step, since that single detail would determine the entire course of the decryption process. A corrupted file system added a further layer of difficulty, turning what might otherwise have been a routine decryption effort into a multi-stage technical process.

1. Media Inspection and Evaluation

After receiving the NAS system, experts inspected all three hard drives to ensure there was no physical damage. The system was then handed over to the RAID data recovery team.

2. RAID Reconstruction

All three hard drives were cloned byte-to-byte before any reconstruction work began. Working from these cloned images, the RAID specialists identified the parameters needed to rebuild the array virtually. These included the 128 KB stripe size, the correct disk order, the distributed parity, and the start offset.

RAID 5 reconstruction is inherently complex due to its distributed parity architecture. This posed no difficulty for the Engineering and Innovation team at Stellar, given their extensive experience with such arrays. With the array successfully rebuilt, the team’s focus shifted to the file system, where they discovered that the ransomware attack had severely damaged the primary superblock.

This stage of the ransomware data recovery process benefited from a feature built into ext4, which stores backup superblocks in multiple locations. A backup superblock was located using proprietary tools and used to create a temporary superblock, restoring readability to the block group descriptor table. This, in turn, made it possible to identify the inode table within each block group.

3. Data Decryption and Recovery

The inode table was subsequently passed to the R&D team for metadata reconstruction. At this stage, the specific Phobos strain was confirmed, which determined the subsequent decryption approach. The data had not been overwritten but had only been encrypted, and this distinction meant that full recovery remained achievable. Proprietary tools were then used to retrieve the client’s data in its entirety.

4. Data Verification and Delivery

Upon completion of the recovery process, a detailed directory listing of all retrieved data was compiled and shared with the client for review. Following confirmation from the client that the data was complete and accurate, the data was transferred to a hard drive provided by the client, and the handover was completed securely and without complication.

Wrapping Up: Do Not Let Ransomware Dictate the Outcome

Business operations rarely emerge unscathed from a ransomware attack. Encrypted data causes downtime, and downtime creates financial pressure, often severe enough that organisations start considering direct contact with the attackers. This is where caution matters most. Paying a ransom guarantees nothing: not a working decryption key, not the attackers’ word, and not even an end to the problem once payment is made. In many cases, it simply invites a repeat attack.

An experienced provider such as Stellar Data Recovery brings a different equation to the table. The Stellar team has the expertise to assess the damage, identify the ransomware variant, and perform RAID data recovery using a strategy tailored to the specifics of the attack, without the risk and uncertainty of negotiating with criminals.

Prevention remains essential, and none of the above diminishes that need. As ransomware attacks continue to rise, small and mid-sized businesses face mounting pressure to treat cybersecurity as a necessity rather than an option. The starting point is a clear understanding of the attack surface, followed by defences configured to address it. Yet even the most careful preparation offers no guarantee of complete protection, which is precisely why a trusted Stellar RAID Data Recover partner is as valuable as prevention.

For any organisation left with an inaccessible RAID server after an attack, help is only a call away. Stellar Data Recovery can be reached at 1800 102 3232 to talk through what recovery would involve, before any ransom is considered.

Every RAID failure has its own challenges, from ransomware attacks and controller failures to corrupted file systems and degraded arrays. Explore these related RAID recovery case studies to see how Stellar Data Recovery resolves complex data loss scenarios.

• Data Recovery from RAID 5 Server (SAS Drives) with Delayed Parity for a Fintech Company
• Enterprise Data Recovery from a RAID 10 Server for an Online Examination Management Service Provider
• Complex SAN Data Recovery From a Multi-LUN SAN With Multiple Disk and RAID 5 Failures for a Data Center
• How 58TB of Critical Video Footage Was Successfully Recovered from a RAID 0 NAS
• Data Recovery From Hacked RAID-5 Server and NAS Box

FAQs

1. Is It Advisable to Pay the Ransom If Data Has Been Encrypted?

Cybersecurity experts generally advise against paying a ransom, since there is no guarantee that attackers will hand over a working decryption key. A more reliable approach is to consult a professional ransomware data recovery firm first, one that can properly assess the extent of the attack and weigh the chances of recovery through decryption or backups before any payment is made.

2. How Long Does Ransomware Recovery Take?

There is no fixed timeline, since so much depends on the specifics involved. A straightforward job might take a matter of days, while a badly damaged file system could stretch that to weeks. Everything starts with identifying the strain, as this shapes the subsequent decryption and restoration work. Where the file system has also been damaged, rebuilding it becomes a necessary step before anything else can begin.

3. Does Stellar Have Expertise in All RAID Levels and Recovery Methods?

Every RAID configuration is within the team’s experience at Stellar, from RAID 0 through to RAID 10. What shifts between engagements is the strategy rather than the underlying capability, since a RAID 6 failure calls for a different approach than a RAID 5 failure, and the extent of the damage further shapes the response. This range of experience is what makes RAID data recovery possible across configurations of varying complexity.

4. How Is the Security of Recovered Data Ensured?

Two certifications underpin this commitment: ISO/IEC 27001:2022 and ISO 9001:2015. Strict security protocols are followed at every stage of an engagement, and access to recovered files remains limited to the personnel directly cleared to work on them.

5. Is Data Recovery Possible From a Ransomware-Affected RAID?

In most instances, yes. The outcome hinges on the specific strain involved, the RAID configuration, and whether the underlying files were overwritten rather than simply locked by encryption. Where recovery can proceed, specialists at Stellar rely on proprietary tools built specifically for this kind of work.