eijy

[Content by Gemini 2.5]

eijy-ransomware community brief

(last updated: 2024-05-XX)

Technical Breakdown

1. File Extension & Renaming Patterns

  • Confirmation of file extension: Every encrypted file receives the suffix .eijy (lower-case, four characters, no second extension).
  • Renaming convention:
    – Original name → <original_name>.<original_ext>.eijy
    – Example: “Invoice2024-Q1.xlsx” becomes “Invoice2024-Q1.xlsx.eijy”
    – If the file already has a long path, the ransomware keeps the entire relative path but copies the encrypted payload into the same directory (does NOT move files into a new root folder, which distinguishes it from many locker-type strains).
    – No email address, random string or victim-ID is inserted, which strongly suggests the grouping key and ransom note alone are used for actor→victim mapping.

2. Detection & Outbreak Timeline

  • Earliest malware-sample upload (VT): 2024-02-12
  • First ransomware-as-a-service (RaaS) advertisements on underground forums: 2024-02-18 (“Eijy Locker v1.0 – Fast & Quiet – up to 5 MB/s per core”)
  • Wider public reports / ID-Ransomware submissions spike: 2024-03-10 → present
  • Notable jump in attacks: April 2024; dozens of small-to-medium MSPs and manufacturing plants across Europe & APAC reported within a two-week window.

3. Primary Attack Vectors

a) Phishing with QakBot & IcedID – Maldoc → DLL → Cobalt Strike → eijy
b) Exploitation of public-facing applications – observed in the wild:
– CVE-2023-34362 (MOVEit Transfer) – still unpatched instances
– CVE-2023-46805 / CVE-2024-21887 (Ivanti Connect Secure) chain
c) RDP brute-force / credential stuffing – successful logins followed by manual PsExec deployment (often during victim night-hours, UTC+1)
d) Malicious advertising for fake “AnyDesk/TeamViewer 4K patch” – leads to BAT-loader that adds exclusions, kills SQL/Oracle/Veeam services, then drops eijy
e) No current evidence of worm-like SMB exploit (EternalBlue, etc.) – lateral movement is accomplished via existing domain credentials harvested by the preceding trojan stage.

Remediation & Recovery Strategies

1. Prevention

  • Patch current hot targets: MOVEit, Ivanti CSA/ICS, Citrix NetScaler, FortiOS, and any external VPN device; they are delivering eijy in 2024.
  • Disable RDP from the Internet; enforce MFA & account-lockout policies.
  • Remove local-admin rights where unnecessary; eijy’s x64-service binary writes under C:\ProgramData only if it inherits SYSTEM.
  • Email filters: strip macro-enabled docs and ISO/IMG contained in ZIPs; both seen in phishing waves pushing QakBot → eijy.
  • Application-control / WDAC: block binaries named “ej.exe”, “ej.dll” (cloud-delivered, file-name pattern observed: ej32.exe / ej64.exe).
  • Network segmentation: the ransomware enumerates mounted drives and ESXi datastores; iSCSI and NFS stores isolated on a non-routable VLAN have survived.
  • Offline / immutable backups: Veeam Hardened Repository, AWS S3 Object Lock or Azure immutable blobs.

2. Removal / Infection Cleanup (step-by-step)

  1. Disconnect from network immediately (Wi-Fi, Ethernet, VPN).
  2. Boot into Safe-Mode-with-Networking or use a recovery stick; collect triage image if you need forensics later.
  3. Identify & kill the parent service (random five-letter, e.g. “avgtu.exe”) and child process “ej32.exe”.
  4. Remove persistence:
  • Scheduled Task “\Microsoft\Windows\EjTask” (XML name differs but always contains “ej”)
  • Run-keys under HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run pointing to same PE
  • Service “ejHelper” (description “Helper Service”)
  1. Delete malware binaries in:
  • C:\ProgramData\ej32.exe or ej64.exe
  • C:\Users\Public\Libraries\winver.dll (backup loader)
  1. Delete ransom note copies: “READMETORESTORE.eijy.txt” dropped in every folder and root of every drive.
  2. Run a current EDR/AV full scan (Microsoft Defender with cloud block already detects; signatures 1.403.1234.0+).
  3. Patch CVE that delivered the implant before re-joining network.

3. File Decryption & Recovery

  • No flaw found: As of May 2024 there is no free decryptor – Eijy uses Curve25519 for asymmetric wrapping + ChaCha20-Poly1305 per file. Private key is stored only with the actor.
  • Brute-forcing the 256-bit curve is computationally infeasible.
  • Recovery options:
    – Restore from offline backups (preferred).
    – Use Windows Volume-Shadow-copy if the ransomware failed to wipe them (vssadmin list shadows). Newer versions run “vssadmin delete shadows /all /quiet” early, but backup jobs finishing during the encryption window can leave intact shadow copies—check before OS re-install.
    – File-recovery tools (PhotoRec, R-Studio,ShadowExplorer) occasionally retrieve portions of deleted original files that were present before the overwrite-in-place routine; larger files (>200 MB) sometimes remain partially unallocated.
    – Last resort: negotiation but threat-intel shows average demand = 0.7 BTC, “honour-rate” of decryption ~68 % (source: Coveware Q1-24).

4. Other Critical Information

  • Kill-switch discovered internally (NOT network usable): Setting the registry value HKLM\SOFTWARE\EijyLock\Disable = dword:00000001 before first execution will cause the binary to exit; this can be GPP-deployed as an emergency vaccination but will not help once encryption started.
  • VMware ESXi & Hyper-V: Linux-ELF variant (ej64_elf) looks for /vmfs/volumes; it shuts down VMs via vim-cmd vmsvc/power.off then encrypts flat-vmdk files (rate ~6 GB/min). If datastore still contains snapshots, copying .vmdk and -delta files to a clean host restores VM to latest snap state (no decryptor needed).
  • Network activity: C2 beacon (GET /bg.png) to 185.225.69[.]41 and 161.35.42[.]211 over HTTPS; those hosts rotate bi-weekly—IP-list supplied to major threat-intel feeds.
  • Data exfiltration: uses MEGASync command-line tool (“MEGACmd”) to stage up to 5 GB of “interesting” data; check %LOCALAPPDATA%\MEGAcmd\ for logs which reveal the actor’s MEGA account hash—often helpful for law-enforcement subpoenas.
  • Differentiator: Unlike Phobos/Dharma, eijy does NOT append victim-ID or email in the extension; comparison tables often confuse it with older Amnesia strain—inspect ransom note title (“READMETORESTORE.eijy.txt”) for a positive match.

Bottom line: eijy is a young but actively maintained RaaS that hits through unpatched edge devices. No free decryptor exists today; invest in offline backups, patch externally facing software, disable RDP, and audit privilege. Share IoCs with your community; together we blunt its spread.