what's a good tool to check if a pdf is not tampered with eg. as a tool to check before loading a pdf from a public bucket to your backend application?
So the model here is, first it gets uploaded to a staging bucket, a lambda/callback checks the validity of the file and then puts it into a safe bucket of which content I trust to put in my server(backend)
apologies my bad. I mean someone uploading a malicious pdf as user input. I am talking beyond calmav and flietype checking, to check if its a valid pdf.
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what's a good tool to check if a pdf is not tampered with eg. as a tool to check before loading a pdf from a public bucket to your backend application?
If you sign the file, you should be able to verify that the signature still matches the file.
How could a PDF be tampered with in your own bucket?
Sounds like they amay be accepting user PDFs, saving them to a bucket, and then doing processing after.
They trust their AWS EC2 instance doing the processing but not their AWS S3 bucket doing the storing? I don't really understand the threat model here.
And what's "public bucket"?
So the model here is, first it gets uploaded to a staging bucket, a lambda/callback checks the validity of the file and then puts it into a safe bucket of which content I trust to put in my server(backend)
I think maybe you are using the word "tampered" in an unusual way? To mean unsafe?
ah apologies again, for this specific one i meant where users from the internet are allowed to upload to. (i am using presigned urls)
apologies my bad. I mean someone uploading a malicious pdf as user input. I am talking beyond calmav and flietype checking, to check if its a valid pdf.