AWS Transfer Family - SFTP File Downloading Issue

1

I have the below Policy for SFTP users, Customer wants WRITE and LIST without GET. Using the below policy, still I can download the file. Can you please give me some suggestion about this.

{ "Statement": [ { "Action": [ "s3:ListBucket", "s3:GetBucketLocation" ], "Effect": "Allow", "Resource": "arn:aws:s3:::mybucket", "Sid": "AllowListingOfUserFolder" }, { "Action": [ "s3:GetObject" ], "Effect": "Allow", "Resource": [ "arn:aws:s3:::mybucket/" ], "Sid": "InboundDirObjectAccess" }, { "Action": [ "s3:PutObject", "s3:GetObject" ], "Effect": "Allow", "Resource": [ "arn:aws:s3:::mybucket///folder1/", "arn:aws:s3:::mybucket///folder2/" ], "Sid": "InboundDirObjectDenyobject" }, { "Action": "s3:PutObject", "Condition": { "StringLikeIfExists": { "s3:delimiter": [ "/" ] } }, "Effect": "Deny", "Resource": "arn:aws:s3:::mybucket//", "Sid": "DenyCreattionFolder" } ] }

已提问 7 个月前388 查看次数
3 回答
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Thanks @Steve_M It's works

已回答 7 个月前
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Firstly, please edit your question to remove the bucket name (obfuscate it and call it something like mybucket instead).

Looking at the actions in the policy and cross-referencing with to https://docs.aws.amazon.com/service-authorization/latest/reference/list_amazons3.html#amazons3-actions-as-permissions

  • "Action": [ "s3:ListBucket" grants permission to list some or all of the objects in an Amazon S3 bucket (which is what you want for the LIST)
  • "Action": [ "s3:PutObject" grants permission to add an object to a bucket (which I think you may also want for WRITE)
  • "Action": [ "s3:GetObject" grants permission to retrieve objects from Amazon S3 (which you don't want for GET)

Consider amending the policy to remove the GetObject permission.

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Steve_M
已回答 7 个月前
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已审核 7 个月前
  • if I remove "Action": [ "s3:GetObject" , in that case SFTP user of Transfer Family, Cannot connect with directory.

  • OK, it's actually more nuanced than that, the policy still need to maintain GetObject for prefixes (so, essentially, you can list the contents of folders), but not for objects (by which we mean files). See https://docs.aws.amazon.com/transfer/latest/userguide/users-policies.html#write-only-access

    provide access to write/upload and list objects in a bucket, but not read/download

    This is exactly what you want isn't it? The policy fragment at the foot of that page is what you need, in particular the DenyIfNotFolder part.

0

if I remove "Action": [ "s3:GetObject" , in that case SFTP user of Transfer Family, Cannot connect with directory.

已回答 7 个月前

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