lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  PHC 
Open Source and information security mailing list archives
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
From: Valdis.Kletnieks at vt.edu (Valdis.Kletnieks@...edu)
Subject: [anti-XSS]about CERT/CC:malicious_code_mitigation 

On Mon, 09 Aug 2004 19:45:07 PDT, dd said:

> Real solution is to have "per input" input validation which will always 
> let some "potentially bad" things through, but help mitigate exposures 
> and then do things "right". 

Actually, you should be doing "per input" validation on each field, which tries
to totally eliminate the "potentially bad" for each field, as appropriate for
the field in question - my example of alphanumeric, space, hyphen, and
underscore may not be suitable for all fields (as one clued person pointed out
to me in private mail).  A real program will almost certainly end up with a
separate filter for each field type....

The *important* part is that you're *not* using 's/[list-of-known-bad]//g',
but that you use 's/[^list-of-known-good]//g'.  Making the known-good list
for each field is the programmer's problem.

How many CGI scripts have had directory traversal issues that would have been
completely and totally prevented if they had done the filtering right and dropped
the '/' character (and probably '.' too) out? ;)

-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 226 bytes
Desc: not available
Url : http://lists.grok.org.uk/pipermail/full-disclosure/attachments/20040810/6fac12a6/attachment.bin

Powered by blists - more mailing lists