[Oisf-users] SMTP filemd5 support

Blair Steven Blair.Steven at alliedtelesis.co.nz
Wed Apr 6 03:57:37 UTC 2016

Hi all,

I am having some trouble with filemd5 and matching attachments in an 
SMTP transaction.

If the test file (EICAR-Test-File) is the first or second attachment the 
MD5 is correctly detected and the transaction is dropped, but if the 
file is attached later the rule is missed.

I've delved into the code, and there is a mis-match in DetectFileInspect 
between file->txid (0) and det_ctx->tx_id (1) - this means the file 
matching never happens.

 From what I can tell this difference comes from freeing the 
SMTPTransaction prior to processing the files (stored on the SMTPState), 
but I can't for the life of me figure out what needs to be done to 
actually get the file processed (and the offending packet dropped).

I'm aware that some of the SMTP file stuff is new and I'm more than 
willing to fix the issue, if I can get some guidance as to what path to 

Thanks very much


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