Broken VECT 2.0 Ransomware Acts as a Data Wiper for Large Files

VECT 2.0 Ransomware Bug Permanently Destroys Large Files

Security researchers have identified a critical implementation flaw in VECT 2.0 ransomware that transforms it into an effective data wiper for large files — permanently destroying file contents rather than encrypting them for ransom. The bug stems from improper handling of encryption nonces, a common but catastrophic mistake in ransomware development that renders large files irrecoverable regardless of whether a victim pays the demanded ransom.

The discovery has significant implications for organizations that have been hit by VECT 2.0: paying the ransom will not restore large files that were processed by the broken encryption routine, because the data has been overwritten beyond recovery.

The Nonce Handling Bug

Modern symmetric encryption — the type used by ransomware to lock victim files — relies on a nonce (number used once) or initialization vector (IV) to ensure that encrypting the same data twice produces different ciphertext. Nonces must be unique for each encryption operation; reusing the same nonce with the same key breaks the confidentiality guarantees of the cipher.

VECT 2.0's flaw involves the nonce management when encrypting large files that span multiple encryption blocks:

What Goes Wrong

When VECT 2.0 processes a large file, it reuses the same nonce across multiple encryption passes over the file. In stream cipher modes (such as ChaCha20 or AES-CTR), nonce reuse causes the keystream to repeat. When a repeating keystream is XOR'd against different file data in subsequent passes, the output is not valid ciphertext that can be reversed — it is garbled, unrecoverable data.

The result is functionally identical to a wiper malware operation: the large file's contents are destroyed.

Implications for VECT 2.0 Victims

Ransom Payment Does Not Restore Large Files

Victims of VECT 2.0 who pay the ransom and receive a valid decryption key will find that:

• Small files are successfully decrypted and restored
• Large files — databases, virtual machine disk images, backup archives, video files, and large documents — are permanently corrupted and cannot be restored even with the correct decryption key

This behavior transforms VECT 2.0 from a reversible ransomware attack into a partial destructive attack for organizations with large critical data assets.

Files Likely Affected

Organizations storing these large file types are at highest risk of permanent loss from VECT 2.0:

VECT 2.0 Background

VECT ransomware has been active in the threat landscape with its 2.0 iteration representing an attempted upgrade of the original codebase. Like many ransomware families, VECT operates on a double-extortion model:

1. Encryption — locking victim files to deny access
2. Data theft — exfiltrating sensitive data before encryption to threaten public release

The nonce bug does not affect the exfiltration component — data that was stolen prior to the broken encryption routine being applied is still in attacker hands and can still be published as leverage.

The Broader Problem: Poor Cryptographic Implementation in Ransomware

This is not the first time a ransomware family has shipped with a broken encryption implementation. Historical examples include:

• WannaCry (2017): Used the same IV for file encryption in some code paths, enabling partial recovery
• Petya/NotPetya (2017): NotPetya's MBR encryption was intentionally non-reversible (wiper), but later analysis showed Petya also had decryptable weaknesses
• Maze/Ragnar Locker variants: Researchers periodically find nonce reuse or key generation bugs in RaaS builder tools
• Hive Ransomware (2022): FBI and researchers cracked Hive's encryption scheme due to flawed keystream generation

The frequency of these bugs reflects the reality that ransomware developers are often not expert cryptographers, and the pressure to ship functional-looking malware quickly leads to implementation shortcuts that break the cryptographic guarantees victims are implicitly trusting when they pay.

What This Means for Incident Response

For organizations dealing with a VECT 2.0 incident:

Do Not Pay Ransom for Large File Recovery

Given the confirmed destruction of large files, paying the ransom solely to recover large files is not advisable — the decryption key cannot undo the damage caused by the nonce bug. Engage with a ransomware recovery specialist who can assess the file-size distribution of encrypted data before making any ransom payment decision.

Prioritize Backup Verification

1. Check if offline backups exist and predate the infection — VECT 2.0, like most ransomware, targets online and connected backup systems first
2. Verify backup integrity — ensure backup archives themselves were not encrypted (and destroyed) by the buggy routine
3. Assess large file exposure — inventory what large files (VMs, databases, archives) were on affected systems

File Recovery Options

Mapping to MITRE ATT&CK

Key Takeaways

• VECT 2.0 ransomware contains a critical nonce reuse bug that permanently destroys large files during the encryption process
• Paying the ransom will not restore large files — the damage is cryptographically irreversible
• Files most at risk include virtual machine images, database backups, large archives, and video recordings
• Offline, air-gapped backups remain the only reliable recovery path for affected large files
• The double-extortion component still applies — stolen data is in attacker hands regardless of the encryption bug
• This incident underscores the value of maintaining verified offline backups as ransomware actors continue to make cryptographic implementation errors that eliminate the path to paid recovery

Sources

• Broken VECT 2.0 ransomware acts as a data wiper for large files — BleepingComputer