Very long filenames?

Julian Field MailScanner at
Fri Feb 22 16:48:02 GMT 2008

Hash: SHA1

Mark Sapiro wrote:
> Bjørn T Johansen wrote:
>> But how long is max length? And is there a way to find the original filename?
> <snip>
>>>> The only option I can find in filenames.rules.conf is this..:
>>>> deny    .{150,}                 Very long filename, possible OE attack
> That regexp matches anything 150 or more characters long. so the max
> length is 149.
> If the message was quarantined, I expect the original name is in the
> quarantined message. If not, there is a MailScanner entry in maillog,
> but I don't know if it has the original or the sanitized name.
The original filename is put in the log. Only sanitised names are ever 
passed back to the user. As far as I am aware, there are no attacks that 
can be launched by putting nasty strings in the call to syslogd. It is 
just truncated to the maximum length of the syslog entry. But there are 
many attacked that can be launched by putting arbitrary strings into 
email messages sent to the user. Just imagine a long filename that 
contained newline sequences and MIME boundaries, you could put an entire 
attachment into a maliciously crafted filename.


- -- 
Julian Field MEng CITP CEng
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