VBK head encrypted by ransomware (first 1 MB) — storage version error, VBM intact, body readable — how to rebuild?

Please ensure to make posts on the community in English as a first point.

You should contact support for this as they will have the people and tools to hopefully help you out.  I would not know how to answer or give good advice here since ransomware is involved.

Hi everyone,

Our Veeam Agent backup file was partially encrypted by ransomware. The encryption was interrupted, and only the first 1 MB of the file is affected.

Details:
- File: dm-1c2 - 192.168.10.x.vbk, ~630 GB
- Error on mount: "Failed to create backup mount source. Storage version [...] is not supported for read-only access" — the header is garbage.
- vbkview fails with "invalid snapshot slot max banks".
- Backup encryption (repository password) was NOT enabled.
- The .vbm metadata file is fully intact and readable (XML, Version 2626).
- Critical IDs: Backup Id = 508d4cc8-d124-4053-b6fb-b4a5190445c6, JobId = d0d61837-77e6-4b8b-8319-fc6a449901db, JobName = dm-1c2, JobType = 12000 (Veeam Agent).
- Hex analysis confirms: everything from offset 1,048,576 onward is intact — zeros, regular index structures, ASCII strings (Veeam, NTFS, file paths), and compressed data. Below 1 MB every sector is random high-entropy data.
- Storage trailer (end of file) is intact.

Questions:
1. Is there a supported procedure to rebuild the storage header of the VBK from the intact VBM metadata and the backup's own trailer/rollup structures?
2. Can V&R or vbkview be pointed at a repaired/stubbed header?
3. Would Veeam support (or a data recovery lab) consider this recoverable? Data loss from the missing 1 MB appears to be metadata only, not VM data.

Running Veeam Agent for Microsoft Windows, target = Default Backup Repository.

Thanks in advance,
[Твой ник]
 

Storage trailer (end of file) is intact — the last ~164 KB contain the OibSummary XML rollup (Storage Id, Point Num=360, block size parameters, OIB details).
 

vbk_tail_oibsummary

Verification done: the VBK tail rollup (last ~164 KB) contains a complete OibSummary 
XML block, and all its key IDs match the intact VBM metadata:
- Backup Id: 508d4cc8-d124-4053-b6fb-b4a5190445c6 (present in VBM)
- JobId: d0d61837-77e6-4b8b-8319-fc6a449901db (present in VBM)
- Storage Id: 819910a4-f3ee-4035-9830-3f8413779020 (present in VBM)
- Point Id: e956af3e-6932-489e-9e66-a33de7736ec1, Num=360 (present in VBM)
- OIB Id: a7db3549-c3c9-4e7b-a739-4d4a842b23be (present in VBM)
- ParentBackupId: d90e608e-9b50-483f-8005-ff484a95ea03 (present in VBM)
Storage parameters from the rollup: BlockSize=KbBlockSize1024, 
BlockAlignmentSize=65536, EncryptionState=0, ApproxSize=1050930719744.
Only the first 1,048,576 bytes of the VBK are encrypted; the VBM, the file body 
and the OibSummary trailer are fully intact and cross-verified.
 

This community page is not support you need to open a support ticket on the Veeam website.  No one here can assist with this issue and it is better you speak to support.

I have the decryptor sent to me by the attacker; it decrypted the files that had their extensions changed, but the .vbk file didn't have its extension changed, and the decryptor isn't fixing it.

​@trofim15 - again contact support no one in the community can help with this.

I reached out, but no one has replied yet. I was told online that I might be able to get help here.

Not really as this is just a community and you need technical support to help with this issue.

Hi Trofim, 

I wrote you from our RND forums but as I see posts here, will share the same information, but in short if you have backup files affected by a Ransomware Attack, always start with a Support Case

Veeam Support has some limited ability to assist on such items, but we cannot always guarantee recovery / full rebuild. Each case will need to be reviewed by Support, and there is internal tooling that has some potential to help recover corrupted / encrypted headers.

But again I must stress that we cannot guarantee recovery in all situations

So please continue with Support; if you have concerns on the case handling / processing, use the Talk to a Manager button from the case portal to contact Support Management.