WD My Cloud CVE-2025-30247 Ransomware Recovery

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.

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 request to the management interface, 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 for My Cloud OS 5. All devices running My Cloud OS 5 firmware older than that version are vulnerable.

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. The architecture detailed below covers single-bay Gen2 units; multi-bay PR/EX/DL models use different SoCs and a different bring-up sequence, but the recovery workflow on the data partition is the same once the drives are imaged.

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.

1. Drive removal and isolation: We remove the 3.5-inch SATA drive(s) from the NAS 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.
2. 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.
3. 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.
4. 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 numbers 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.
5. 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).
6. Bridge-chip encryption check during triage: Before assuming a recovered drive is unencrypted, we verify how it was wired. Single-bay My Cloud NAS units route data through the native Marvell Armada SoC SATA path and write to ext4 with no bridge chip in the way, so a clone reads back as plaintext ext4. WD My Book and other external-USB-enclosure models are the opposite case: those route the drive through a JMicron or Symwave USB-to-SATA bridge chip that enforces hardware AES-256 on the PCB. If the recovered drive came from one of those enclosure-bridge models, a shucked drive read on a plain SATA port returns cipher-text even when the owner never set a password. Recovering that data means extracting the AES key through firmware manipulation of the bridge chip or sourcing a compatible donor bridge chip, not simply cloning the platters. This is the WD My Book external-enclosure encryption trap, and it is why bridge-chip status is part of triage rather than an assumption.
7. 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.

How Much Does CVE-2025-30247 Recovery Cost?

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.