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Introduction:
A new Windows ransomware family codenamed “Payload” has emerged as a significant threat, leveraging a sophisticated hybrid encryption scheme that combines the ChaCha20 stream cipher with a per-file Curve25519 Elliptic-Curve Diffie-Hellman (ECDH) key exchange. This architectural choice renders victim data unrecoverable without the attackers’ private key. Compounding this cryptographic strength, Payload employs a suite of aggressive anti-forensics measures—including Event Tracing for Windows (ETW) patching, Volume Shadow Copy (VSS) deletion, and event log wiping—to cripple detection and recovery efforts, marking a dangerous evolution in ransomware tradecraft.
Learning Objectives:
- Understand Payload’s hybrid ChaCha20/Curve25519 encryption pipeline and why it makes data recovery impractical without the attacker’s private key.
- Learn how Payload weaponizes anti-forensics techniques, including ETW memory patching, VSS deletion, and Windows Event Log clearing.
- Acquire practical commands and detection strategies to identify malicious activity, terminate ransomware processes, and harden Windows endpoints against such attacks.
You Should Know:
1. Deep Dive Into Payload’s Babuk‑Inspired Hybrid Cryptography
Payload ransomware traces its cryptographic lineage directly to the leaked Babuk 2021 source code, which it adapts for modern evasion and cross-platform targeting. The Windows executable deploys ChaCha20 for file encryption—a fast stream cipher known for its resistance to timing attacks—while generating a fresh Curve25519 ECDH key pair for every single file. This per‑file keying is critical: even if one file’s ephemeral key is recovered, the rest remain locked. For each file, the malware generates a unique 32‑byte victim private key and a 12‑byte nonce using CryptGenRandom, securely wiping them from memory after use. The shared secret derived from the attacker’s embedded master public key is then used directly as the ChaCha20 key, with no additional key derivation function—a streamlined design that leaves no room for embedded backdoors. Each encrypted file receives the `.payload` extension and is appended with a 56‑byte RC4‑encrypted footer (using the three‑byte key FBI) that stores the victim’s ephemeral public key and nonce, ensuring only the attacker can decrypt.
The group has adopted a classic double‑extortion model: data exfiltration followed by file encryption and public shaming on a dedicated Tor leak site. By March 2026, Payload had listed 50 victims across Egypt, Mexico, Poland, and other regions, demonstrating a remarkable global footprint within weeks of its February 2026 debut.
- The Anti‑Forensics Arsenal: ETW Patching, VSS Deletion, and Event Log Wiping
Payload’s anti‑detection capabilities are as sophisticated as its encryption. Before encryption begins, the malware patches Event Tracing for Windows (ETW) in user mode by modifying the address of the `NtTraceEvent` function inside ntdll.dll, effectively replacing its syscall stub with a simple `RET` instruction. This blinds EDR solutions that rely on ETW for real‑time process monitoring. After ETW is neutered, the ransomware systematically enumerates and deletes all Volume Shadow Copy Service (VSS) snapshots using administrative commands, permanently blocking OS‑level system restore. It also clears Windows Event Logs to erase its tracks, often using `wevtutil` to wipe the Security, System, and Application logs. Finally, Payload aggressively terminates backup and security software processes and services, ensuring no interference during the encryption phase.
Step‑by‑Step Practical Guide to Countermeasures
The following commands and configurations are designed for incident responders and defenders. Execute them with appropriate privileges.
Detecting and Terminating a Suspicious Process (Windows)
Identify the ransomware process by name or PID and terminate it. Use `Get-Process` to list running processes, filtering for suspicious names such as random‑letter executables or those making unusual network connections.
| PowerShell Command | `Get-Process | Where-Object { $_.ProcessName -like “payload” -or $_.ProcessName -match “^[a-z]{8}$” } | Stop-Process -Force` |
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| CMD Command | `taskkill /F /IM suspicious.exe` |
Restoring from Volume Shadow Copies (If Still Intact)
Before an attacker deletes them, shadow copies can be listed and restored. If deletion has occurred, these commands will return empty—a strong indicator of compromise.
| List Shadow Copies (CMD as Admin) | `vssadmin list shadows` |
| | |
| Restore a Specific Shadow Copy | `vssadmin list shadows` (copy the Shadow Copy ID), then `vssadmin delete shadows /shadow={SHADOW_COPY_ID}` (warning: this deletes; restoration typically requires mounting the shadow copy as a read‑only volume using `mklink` or third‑party tools; for actual restore, use `diskshadow` with an `EXPOSE` command). A more robust restoration method uses the `diskshadow` utility: create a script file `restore.txt` containing set context persistent nowriters, add volume C:, create, expose %shadowid% Z:, then run `diskshadow /s restore.txt` to expose the shadow copy as drive Z: for file‑level recovery. |
| Prevent Deletion (Group Policy) | Configure `gpedit.msc` → Computer Configuration → Administrative Templates → System → Volume Shadow Copy Service → “Deny shadow copy deletion” (not available in all Windows editions; alternatively, set strict NTFS permissions on the shadow copy storage area). |
Clearing and Preserving Windows Event Logs (Defender’s Perspective)
Attackers use `wevtutil` to clear logs, but responders can also use it to archive logs before they are wiped—or to detect that a wipe occurred.
| Archive All Logs Before Investigation | `wevtutil epl System C:\Logs\System_Backup.evtx` and repeat for Application, Security, etc. |
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| Detect Log Clearing | Monitor Event ID 1102 (Security log cleared) and 104 (System log cleared). |
3. ETW Patching Detection and Hardening
Payload patches ETW in memory by overwriting the `NtTraceEvent` syscall stub. Defenders can detect this by comparing the in‑memory bytes of `ntdll.dll` with the disk version.
| Detect ETW Patching (PowerShell) | `Compare-Object (Get-Content C:\Windows\System32\ntdll.dll -Raw) (Get-Content -Path (Get-Process -Id $pid).Modules` |
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| Recommended EDR Configuration | Deploy EDR solutions that rely on kernel‑mode callbacks (e.g., PsSetCreateProcessNotifyRoutine) rather than solely user‑mode ETW, as kernel‑mode monitoring cannot be bypassed by patching ntdll.dll. |
4. Vulnerability Exploitation and Mitigation
Payload typically gains initial access through spear‑phishing or exploited public‑facing applications. Organizations should enforce application allowlisting, restrict PowerShell execution policy, and deploy Endpoint Detection and Response (EDR) with behavioral analysis. A multi‑layered defense—including regular offline backups, network segmentation, and rigorous patch management—remains the most effective mitigation.
What Undercode Say:
- The Hybrid Encryption Trap: Payload’s per‑file Curve25519 key exchange combined with ChaCha20 creates a cryptographic wall. Without the operator’s private key, decryption is mathematically infeasible, making traditional recovery methods obsolete.
- The New Ransomware Standard: By weaponizing ETW patching, VSS deletion, and log wiping as core features, Payload sets a new benchmark for anti‑forensic maturity. Defenders must shift from reactive recovery to proactive detection, leveraging kernel‑based monitoring and immutable backups.
Prediction:
The integration of advanced anti‑forensics directly into ransomware binaries—rather than as separate “helper” tools—will become the norm by 2027. Payload’s emergence signals a future where ransomware families prioritize operational security as heavily as encryption strength. Expect to see more cross‑platform variants (Windows and ESXi) and the adoption of additional evasion techniques such as direct system call invocation and dynamic API resolution. For defenders, this evolution demands investments in kernel‑level visibility, offline backup strategies, and continuous threat hunting. Organizations that fail to adapt will face not only encrypted data but also blindfolded security tools and erased recovery paths.
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Reported By: Mayura Kathiresh – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅
