Altair Ransomware: Removal & Recovery

Introduction

The Altair ransomware executes targeted attacks across corporate networks by encrypting critical data volumes in place. During infection, operational documents such as project_proposal.docx are renamed to project_proposal.docx.altair19, while central databases like inventory.sql are rendered unreadable as inventory.sql.altair40. Beyond file encryption, Altair drops an HTML extortion manifest titled RANSOM_NOTE.html, configures persistent system hooks, and utilizes double-extortion strategies by threatening public disclosure of proprietary assets.

Related article: How to Remove Regulus Ransomware and Protect Your Data?

The Altair Decryptor Tool: Your Best Bet for Data Recovery

Recovering files encrypted by Altair requires specialized forensic reconstruction to parse cryptographic structures without risking data corruption. An enterprise-grade Altair Decryptor solution allows organizations to evaluate file headers, extract active symmetric keys from volatile runtime artifacts, and reverse cipher structures without interacting directly with extortionists.

Targeting Virtual Infrastructures: Altair’s Attack on ESXi

What is Altair Ransomware for ESXi?

The Altair payload includes targeted capabilities against VMware ESXi hypervisors. Because enterprise workloads, enterprise resource planning (ERP) systems, and production databases reside within virtual disks, attacking the virtualization layer allows threat actors to compromise multiple production servers in a single pass.

How it Works: Key Features and Tactics

• ESXi Targeting: Threat actors target management interfaces, brute-force SSH credentials, or exploit unpatched hypervisor services to gain root shell execution.
• Encryption Algorithms: Altair systematically terminates active virtual machine processes and locks .vmdk, .vmx, and .vmem files using high-velocity hybrid ciphers.
• Extortion Tactics: Operators enforce a 72-hour negotiation window, threatening key destruction and data dissemination on the dark web if ransom conditions are not met.

The Impact on ESXi Environments

Infiltrating a hypervisor halts core infrastructure instantly, producing total operational downtime, disrupted service delivery, and potential data integrity loss across virtualized datastores.

Windows Servers Under Siege: Altair Ransomware’s Assault

Understanding Altair Ransomware for Windows Servers

On Windows endpoints and servers, Altair establishes administrative persistence, drops executables into AppData\Local or AppData\Roaming, and initiates defensive evasion routines to prevent automated discovery.

Methods and Features of the Attack

• Service Termination & Shadow Copy Purge: Altair automatically issues commands including vssadmin.exe Delete Shadows /All /Quiet to eliminate Volume Shadow Copies and stop active database engines (SQL, Exchange) to free file handles.
• Persistence Mechanisms: Configures automated scheduled tasks to execute every 15 to 20 minutes alongside modifications to HKCU\SOFTWARE\PAIDMEMES or standard Run registry keys.
• Ransom Demands: Mandates contact via designated email addresses (recovery2@salamati.vip, recovery2@amniyat.xyz) or private Tor negotiation portals.

Consequences for Windows Servers

Compromised Windows systems face immediate operational failure, exposure of unencrypted data through pre-encryption exfiltration, and severe compliance liabilities under data privacy mandates.

How to Use the Altair Decryptor Tool for Recovery?

Navigating an Altair infection safely requires methodical forensic steps:

1. Secure Intake: Submit isolated file samples (such as .altair19 files) alongside the RANSOM_NOTE.html manifest for forensic validation.
2. Cryptographic Analysis: Engineers analyze the sample structure to confirm the key ID, assess whether the encryption pass was interrupted, and evaluate unallocated space for intact file remnants.
3. Key Reconstruction: The specialized decryptor parses the embedded metadata blocks to isolate the file keys.
4. Supervised Restoration: Decryption routines run on cloned disk images to verify integrity before restoring production systems to service.

Why Choose the Altair Decryptor Tool?

• Data Integrity Protection: Recovery runs strictly on sector-level mirrors, eliminating the risk of permanent file corruption from untrusted decoders.
• Independent Operations: Bypasses extortion communication entirely, preserving compliance and reporting standards.
• Database and VM Specialization: Reconstructs large structured files (such as SQL tables and VMDK containers) that often suffer block corruption during standard decryption passes.
• Transparent Evaluation: Initial forensic intake assesses whether file repair or carve extraction is mathematically viable before initiating recovery.

Recognizing an Altair Ransomware Attack

Confirming an Altair intrusion relies on identifying several key environmental indicators:

• Numerical Extensions: File names end in patterns like .altair19, .altair20, .altair40, .altair60, or .altair90.
• Extortion Note Deployment: The file RANSOM_NOTE.html is present across all modified directories.
• Persistence Artifacts: Unexpected scheduled tasks running at recurring intervals from user AppData paths.

Context of the Altair Ransom Note:

Encryption Methods Employed by Altair

Altair implements hybrid cryptography standard within the MedusaLocker lineage:

• Symmetric Encryption: Files are encrypted using AES-256 to rapidly lock high volumes of data.
• Asymmetric Wrapping: Symmetric file keys are wrapped with an embedded RSA public key, preventing local extraction of keys without access to the corresponding private key.

Building a Unified Defense Against Altair

Mitigating MedusaLocker-derived variants requires layered network and infrastructure hardening:

• Eliminate Exposed Remote Services: Never leave RDP ports (3389) open to the internet; enforce VPN tunnels secured with Multi-Factor Authentication (MFA).
• Immutable Backups: Maintain isolated, off-site backups configured under Write-Once-Read-Many (WORM) policies to prevent unauthorized deletion.
• Network Segmentation: Isolate management VLANs, storage networks (NAS/SAN), and hypervisor consoles from standard user subnets.
• Endpoint Privilege Management: Enforce the principle of least privilege, restricting standard user permissions and applying application whitelisting across domain servers.

Understanding the Ransomware Attack Cycle

1. Initial Infiltration: Threat actors gain access through compromised remote credentials, phishing vectors, or vulnerable network edge appliances.
2. Reconnaissance & Privilege Escalation: Attackers traverse internal subnets, map storage resources, and harvest elevated credentials.
3. Data Exfiltration: Proprietary documents and databases are staged and uploaded to external command infrastructure.
4. Payload Execution: Altair deletes volume snapshots, terminates core services, and encrypts files across local and mapped storage volumes.

Consequences of an Altair Incident

An unresolved Altair attack can trigger severe consequences, including extended operational downtime, irreversible data loss, high incident response and remediation costs, and legal or regulatory penalties stemming from exfiltrated sensitive records.

Free Alternatives for Data Recovery

Before considering commercial recovery, evaluate standard technical alternatives:

• Verified Offline Backups: Restore clean volumes from air-gapped or immutable storage targets.
• Public Decryption Repositories: Monitor portals such as the No More Ransom Project for newly released decryptors or master keys.
• Unallocated Space Carving: In cases of interrupted encryption, raw data carving tools (e.g., PhotoRec) may locate intact temporary copies of documents in unallocated sectors.

Conclusion

Altair (MedusaLocker) ransomware presents a severe challenge to enterprise continuity through its dual strategy of high-speed encryption and data theft. Containing the breach quickly, preserving memory and disk artifacts, and executing recovery on sterile copies prevents irreversible file loss and removes reliance on cybercriminal syndicates. Implement stringent access controls and maintain verified, immutable backups to defend your organization against evolving ransomware strains.