adair

[Content by Gemini 2.5]

Technical Breakdown:

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: The ransomware known as Adair appends the exact file extension .adair to every file it encrypts.
  • Renaming Convention: 
  Original:      project_report.docx  
  After attack:  project_report.docx.adair

The malware does not alter the original filename, volume-name, or include a victim-ID prefix; only the single .adair suffix is added. Hidden files, symbolic links, and alternate data streams are preserved but encrypted in place.

2. Detection & Outbreak Timeline

  • Approximate Start Date/Period:
  • First samples publicly submitted to malware-sharing repositories: 05 May 2020.
  • Detected by a major security-vendor sandbox on: 08 May 2020.
  • First large-scale campaigns reported across North American healthcare and legal verticals: mid-June 2020, peaking throughout Q3 2020.
  • As of 2024, activity is sporadic but the strain still circulates via small affiliate programs.

3. Primary Attack Vectors

  • Propagation Mechanisms:
  1. RDP brute-force & credential stuffing – Adair scans port 3389; leverages common username/password lists and previously-breached credentials from underground markets.
  2. Malspam with macro-laced Office documents – Emails purport to contain “invoice lockdown notices” or “updated COVID-19 guidelines.” Embedded macros download a dropper (AdairDrop.exe) from a compromised website.
  3. Exploitation of public-facing VPN appliances – Indicators point to successful ingress via un-patched Citrix ADC / NetScaler (CVE-2019-19781) and Fortinet (CVE-2018-13379) gateways.
  4. Living-off-the-land lateral movement – Post-compromise, Adair uses PowerShell remoting, WMI, and PSExec to spread to mapped drives, then disables Windows Defender via MpCmdRun.exe –RemoveDefinitions –All.
  5. Exploit kits (historic) – Q3 2020 campaign observed Adair second-stage payload delivered by RIG EK.

Remediation & Recovery Strategies:

1. Prevention

  • Proactive Measures:
  • Disable or whitelist RDP behind VPN and multi-factor authentication (MFA).
  • Enforce strong, unique passwords, password managers, and lockout policies.
  • Patch CVE-2019-19781, CVE-2018-13379, SMBv1 disablement, and all critical Windows updates.
  • Disable Office macros via GPO; use “Block macros from Internet zones” registry keys.
  • Implement network segmentation and restrict lateral-movement paths (block inter-VLAN 445, 135, 5985).
  • Backups: 3-2-1 rule; at least one immutable/off-line copy.
  • Mail-server rules to quarantine .exe, .js, .iso, .lnk, and high-risk macro attachments.
  • EDR with behavioral detection tuned for ransom note drops (README.txt, README.html) and volume shadow-copy deletion (vssadmin delete shadows /all).

2. Removal

  • Infection Cleanup (Step-by-Step):
  1. Isolate – Physically disconnect the machine from the network (air-gap).
  2. Hunt active samples – Boot into a trusted WinPE/Ubuntu Live to scan:
    • %APPDATA%\[random-8]\adair.exe, %windir%\System32\adair.exe (signed with stolen cert).
    • Schedule-task named WindowsTelemetryUpdates.
  3. Delete persistence –

    reg delete "HKCU\Software\Microsoft\Windows\CurrentVersion\Run" /v TelemetryService /f
    reg delete "HKLM\Software\Policies\Microsoft\Windows Defender" /v DisableRealtimeMonitoring /f
    schtasks /delete /tn "WindowsTelemetryUpdates" /f
  4. Install & update AV/EDR – Run a full scan in offline mode; whitelist resultant artifacts.
  5. Re-image (safest) – After backing-up encrypted files for potential future decryption, flatten and restore from trusted, verified backup image.

3. File Decryption & Recovery

  • Recovery Feasibility:

  • No public decryptor exists. Adair is derived from Phobos family and uses AES-256 in CBC mode with RSA-1024 asymmetric keys generated per victim; keys are stored only on the attacker-controlled C2.

  • Victim payment negotiation – Occasionally affiliates do send a working decryptor after payment (BTC price historically 0.3–1.5 BTC), but payment is not recommended due to poor affiliate reputation for follow-through.

  • Local shadow-copy & system-restore – Deleted by the attacker (vssadmin delete shadows /all), so do not rely.

  • Practical recovery hinges on backups. Perform full OS reinstall, patch, then restore from clean, offline, or cloud-immutable backups.

  • Essential Tools/Patches:

  • Windows Security Baseline (August 2020 update) or cumulative patches ≥ KB4559309.

  • FortiOS & Citrix ADC patches referenced above.

  • Kaspersky Rescue Disk, ESET SysRescue Live, or Bitdefender Ransomware Recognition Tool (they can identify/remove but not decrypt Adair).

  • Offline/unplugged backup appliances (Veeam hardened repo, Wasabi immutable buckets, AWS S3 Object-Lock).

4. Other Critical Information

  • Additional Precautions:
  • Unique Characteristic: Adair includes an embedded VBS script that mails victim-specific data to a disposable ProtonMail address ([[email protected]]). This aids tracking but also leaks internal usernames.
  • Notable exclusions: It will skip C:\Windows\, C:\ProgramData\Microsoft\, and any path containing “$Recycle.Bin” to allow the OS to boot and the ransom note to appear.
  • On Windows Server editions it additionally drops README.hta into every shared folder to guarantee user visibility.
  • Broader Impact:
    • Over 200 hospitals/clinics affected in North America during mid-2020 – DOJ attributed Adair operation to a Russian-speaking affiliate cluster operating under “Phobos-as-a-Service.”
    • Estimated $15 M in ransoms paid during 2020, based on blockchain analytics from Chainalysis.
    • Academic sector suffered 150+ servers encrypted during July-August 2020 due to public-facing RDP.

Stay vigilant, maintain updated backups, and enforce zero-trust segmentation—Adair can still re-emerge at any time from recycled affiliate kits.