WD My Cloud CVE-2025-30247 Ransomware Recovery

CVE-2025-30247 is an unauthenticated OS command injection vulnerability in WD My Cloud OS 5 firmware prior to v5.31.108. Attackers exploit it via HTTP POST to deploy ransomware on the internal ext4 data partition. Updating firmware closes the hole but does not decrypt already-encrypted files. We recover data by imaging the internal SATA drives offline through PC-3000, reconstructing corrupted ext4 superblocks, and carving surviving plaintext from journal entries and unallocated space. No data = no charge.

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Written by

Louis Rossmann

Founder & Chief Technician

Updated March 2026

10 min read

What Is CVE-2025-30247?

CVE-2025-30247 is a critical remote code execution (RCE) vulnerability in the web management interface of WD My Cloud OS 5 firmware versions prior to v5.31.108. It carries a CVSS 4.0 score of 9.3. The root cause is insufficient input sanitization in backend PHP scripts that handle HTTP POST requests: user-supplied parameters reach shell functions without neutralization of metacharacters such as ;, &&, and |. An attacker sends a crafted POST to the /cgi-bin/webproc endpoint, injecting arbitrary system commands that execute with the web server's privileges.

No authentication or user interaction is required. Any My Cloud device with its management interface exposed to the internet is a target. Once inside, attackers download and execute ransomware payloads that encrypt the ext4 user data partition.

Affected Devices and Firmware

Western Digital released patched firmware v5.31.108 on September 23, 2025. All devices running My Cloud OS 5 firmware older than that version are vulnerable.

Multi-Bay Models

My Cloud PR2100 / PR4100
My Cloud EX2 Ultra / EX4100
My Cloud EX2100
My Cloud Mirror Gen 2
My Cloud DL2100 / DL4100 (end-of-life; no patch available)

Single-Bay Models

My Cloud (WDBCTL series)
My Cloud single-bay (all generations running OS 5)

DL2100 and DL4100 units have been officially discontinued by WD and may not receive the patch, making them permanently vulnerable if connected to the internet.

Why Firmware Updates Do Not Decrypt Encrypted Data

Updating to firmware v5.31.108 closes the OS command injection vector. Future exploitation through this specific HTTP POST path is blocked. The patch modifies the PHP input handling to sanitize shell metacharacters before they reach system calls.

The patch does not interact with the data partition. If ransomware has already encrypted files on the ext4 volume (or encrypted the volume itself via LUKS/cryptsetup), those files remain encrypted after the firmware update. A factory reset also does not help; it re-initializes the OS partitions and erases the GPT partition table metadata, but the encrypted user data remains locked.

Do not factory reset. Factory reset erases the GPT layout and mdadm RAID metadata without decrypting any data. This destroys filesystem references needed for forensic extraction. Power off the NAS and remove the drives.

WD My Cloud Internal Architecture

Understanding the hardware layout matters for recovery because the forensic approach differs between single-bay and multi-bay models, and the SoC dictates the partition structure.

Marvell Armada 375 SoC

CPU: Dual-core ARM Cortex-A9, 800 MHz to 1.0 GHz (ARMv7 architecture)
RAM: 512 MB DDR3
Storage interface: Dual native SATA 2.0 ports. Drives connect directly to the SoC; no USB-to-SATA bridge in the data path
Crypto engine: Hardware AES acceleration present on the SoC

Partition Layout (GPT)

Boot partitions: Linux kernel, u-boot bootloader, and OS root filesystems (ext2/ext3) occupy the first several GPT partitions
User data: The largest partition (end of disk) is formatted ext4 and holds all user files
Multi-bay: The ext4 data partition sits on a Linux mdadm software RAID volume. RAID 0, 1, 5, or JBOD depending on configuration

Ransomware Encryption Patterns on WD My Cloud

NAS ransomware payloads fall into three categories. The recovery path depends on which type encrypted the data.

1. File-Level Encryption

The ransomware traverses the mounted ext4 volume and encrypts individual files using AES-256 with RSA key exchange. Known variants append extensions like .0xxx. The encryption process reads the original file, writes an encrypted copy, then deletes the original. Deleted plaintext data may survive in ext4 unallocated space if the drive has not been heavily written to since the attack. This is the most recoverable scenario via journal carving and inode recovery.

2. Volume-Level Encryption (LUKS/cryptsetup)

Because My Cloud runs Linux, the cryptsetup binary is present on the device. If an attacker uses it to encrypt the entire block device via LUKS, the volume becomes mathematically inaccessible without the passphrase. If full-volume LUKS encryption occurred, recovery of the encrypted data is not possible without the key. We check whether the LUKS header was applied before or after user data was written, which occasionally reveals unencrypted sectors in the gap between the old ext4 boundary and the LUKS container.

3. Metadata Destruction (Wiper Behavior)

Some payloads destroy filesystem metadata (superblocks, group descriptors, inode tables) to render the partition raw and unmountable. The user data remains on the platters in plaintext, but the operating system cannot locate file boundaries or directory trees. This pattern is the most recoverable in a lab setting because the data itself is not encrypted; only the map to the data is destroyed. We reconstruct from ext4 backup superblocks and journal entries.

Forensic Recovery Procedure

Every step operates on cloned images. The original customer drives are never modified. This workflow applies to both single-bay and multi-bay WD My Cloud devices.

Drive removal and isolation: We remove the 3.5-inch SATA drive(s) from the Marvell Armada 375 enclosure. The NAS is never powered on again; all subsequent work happens offline. Drives with mechanical symptoms (clicking, non-spinning) go through head swap or firmware repair in our 0.02 micron ULPA clean bench before imaging.
Write-blocked forensic imaging via PC-3000: Each drive is connected to a hardware write-blocker and cloned sector-by-sector using PC-3000 Data Extractor. The write-blocker prevents any modification to the evidence drive. If the drive has bad sectors or read instability, PC-3000's adaptive retry algorithms map around damaged regions and capture maximum data.
RAID reconstruction (multi-bay only): For EX2 Ultra, PR2100, PR4100, and other multi-bay units, we parse the mdadm superblocks from each member drive image to determine stripe size, disk order, and parity rotation. The RAID array is reassembled virtually from the cloned images without touching the originals.
Ext4 superblock restoration: If ransomware corrupted the primary ext4 superblock, the filesystem will not mount (the drive reports "Bad magic number in super-block"). Ext4 stores the superblock signature 0xEF53 at offset 0x38 in the primary superblock. Backup copies exist at block groups 32768, 98304, 163840, 229376, and 294912. We locate a valid backup using mke2fs -n (dry-run mode; writes nothing) and restore via e2fsck -b 32768 on the forensic clone.
Journal carving and inode recovery: The ext4 journal records metadata changes before they are committed to the main filesystem. We parse uncommitted transactions and roll back recent journal entries to recover the filesystem state from immediately before the ransomware executed. This rescues deleted plaintext files from unallocated space when the ransomware used file-level encryption (read-encrypt-delete cycle).
Data extraction and verification: Recovered files are extracted, verified for integrity, and delivered on target media. We provide a file listing before shipping so you can confirm the recovery meets your needs.

Actions That Destroy Recoverable Data

Community forums show recurring patterns where users permanently destroy data that would otherwise be recoverable.

Connecting the drive to Windows: Windows cannot read ext4. When you connect the internal drive, Windows prompts to "Initialize" or "Format" the disk. Clicking either option overwrites the GPT partition table and destroys the ext4 superblock.
Running fsck on the live NAS: fsck is designed to make a filesystem consistent, not to preserve user data. On a ransomware-damaged filesystem, it orphans or deletes thousands of entries to restore mountability, permanently destroying the inode references needed for journal-based recovery.
Triggering a RAID rebuild while infected: On multi-bay units, swapping a drive or forcing a rebuild while ransomware is still active causes parity recalculations that embed the encrypted data across all surviving members. The pre-attack data is overwritten by parity writes.
Factory reset: Erases the GPT partition table and mdadm configuration. Does not decrypt anything. Destroys the filesystem metadata needed for forensic extraction.

CVE-2025-30247 Recovery Pricing

Pricing follows our standard hard drive recovery tiers because the internal drives are standard 3.5-inch SATA HDDs. The complexity depends on the ransomware type (metadata destruction vs. file-level encryption vs. full-volume LUKS) and whether the drive has mechanical damage.

Metadata / Logical Recovery

Superblock restoration, ext4 journal carving, inode recovery from unallocated space

$250–$900

Multi-Bay Array + Forensics

mdadm RAID reconstruction from cloned images plus ext4 extraction

$600–$900

Mechanical + Ransomware

Head swap or firmware repair required before imaging the ransomware-affected volume

$1,200–$1,500

No Data = No Charge. If we cannot recover usable data, you pay nothing.

CVE-2025-30247 Recovery FAQ

Will updating my WD My Cloud firmware to v5.31.108 decrypt my files?

No. Firmware v5.31.108 patches the OS command injection vulnerability so attackers cannot re-enter through the same vector. It does not reverse encryption applied by the ransomware payload. Encrypted files remain encrypted after the update. A factory reset also does not decrypt files; it erases the partition table and RAID metadata, making recovery harder.

Is it safe to factory reset my hacked WD My Cloud?

No. A factory reset erases the GPT partition table and mdadm RAID configuration without touching the encrypted data. You lose the filesystem metadata needed to locate surviving unencrypted fragments. Remove the drives from the enclosure, leave them powered off, and ship them to the lab.

Can you recover data if only some files were encrypted?

File-level ransomware reads the original file, writes an encrypted copy, then deletes the original. The deleted plaintext data may still exist in ext4 unallocated space if the disk has not been heavily written to since the attack. We image the drive through a write-blocker using PC-3000, then carve deleted inodes from the ext4 journal and unallocated sectors. The earlier you power off the NAS after discovering the infection, the more unencrypted data survives.

My EX2 Ultra was in RAID 1. Can I recover from just one drive?

RAID 1 mirrors data across both drives. If ransomware encrypted both members identically, both mirrors contain the same encrypted data. If the attacker only encrypted the mounted volume (the logical mdadm array) but not the raw blocks underneath, we may recover pre-encryption data from raw sectors on either member. We image both drives and compare their unallocated regions for surviving plaintext fragments.

Data Recovery Standards & Verification

Our Austin lab operates on a transparency-first model. We use industry-standard recovery tools, including PC-3000 and DeepSpar, combined with strict environmental controls to make sure your hard drive is handled safely and properly. This approach allows us to serve clients nationwide with consistent technical standards.

Validated Clean Zone

Open-drive work is performed in a ULPA-filtered laminar-flow bench, validated to 0.02 µm particle count, verified using TSI P-Trak instrumentation.

Transparent History

Serving clients nationwide via mail-in service since 2008. Our lead engineer holds PC-3000 and HEX Akademia certifications for hard drive firmware repair and mechanical recovery.

Media Coverage

Our repair work has been covered by The Wall Street Journal and Business Insider, with CBC News reporting on our pricing transparency. Louis Rossmann has testified in Right to Repair hearings in multiple states and founded the Repair Preservation Group.

Aligned Incentives

Our "No Data, No Charge" policy means we assume the risk of the recovery attempt, not the client.

Technical Oversight

Louis Rossmann

Louis Rossmann's well trained staff review our lab protocols to ensure technical accuracy and honest service. Since 2008, his focus has been on clear technical communication and accurate diagnostics rather than sales-driven explanations.

We believe in proving standards rather than just stating them. We use TSI P-Trak instrumentation to verify that clean-air benchmarks are met before any drive is opened.

See our clean bench validation data and particle test video