This was on the blog....
YARA rules using any of the following features will be flagged in error,
and the respective rules will be disabled:
Single byte YARA string components – currently in the ClamAV matcher, all
strings, as well as components of strings delimited by wild cards, must be
at least two bytes in length
External variables – variables referenced in YARA conditions whose value
may be set using the ‘yara –d’ command line option.
Cheers,
Steve
Web: sanesecurity.com
Blog: sanesecurity.blogspot.com
Twitter: @sanesecurity
On 11 August 2016 18:33:49 Axb <axb.li...@gmail.com> wrote:
In that post aithor states:
"I created some YARA rules that use the external variable „filename“ to
work. LOKI and THOR use the „filename“ and other external variables by
default."
hmm... now how the heck do we get to happen with ClamAv? :)
.. talking to myself...
On 08/11/2016 07:29 PM, Axb wrote:
Found it!
https://www.bsk-consulting.de/2015/12/22/yara-rules-to-detect-uncommon-system-file-sizes/
see "rule Suspicious_Size_chrome_exe" and others...
Assumed it was a "legal" keyword.
On 08/11/2016 07:26 PM, Axb wrote:
I picked the filename condition from a sample rule on a web site with a
number of yara rules.
Too bad I didn't bookmark it...
Will try to find it again.
On 08/11/2016 05:08 PM, Steven Morgan wrote:
filename does not appear as a yara keyword:
http://yara.readthedocs.io/en/latest/writingrules.html
Is it a new keyword not yet in a released version of yara? Did you mean
filesize?
On Thu, Aug 11, 2016 at 5:21 AM, Axb <axb.li...@gmail.com> wrote:
Guys,
clamscan --database=test.yar blah.html
LibClamAV Error: yyerror(): test.yar line 6 undefined identifier
"filename"
LibClamAV Error: cli_loadyara: failed to parse rules file test.yar,
error
count 1
test.yar: OK
blah.html: OK
test.yar
rule TEST_BLAH_FILENAME
{
strings:
$BLAH = "blah"
condition:
$BLAH and filename == "blah.html"
}
Am I missing something? or is filename unsupported by ClamAV's YARA
engine?
Thanks!
Axb
_______________________________________________
Help us build a comprehensive ClamAV guide:
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_______________________________________________
Help us build a comprehensive ClamAV guide:
https://github.com/vrtadmin/clamav-faq
http://www.clamav.net/contact.html#ml
_______________________________________________
Help us build a comprehensive ClamAV guide:
https://github.com/vrtadmin/clamav-faq
http://www.clamav.net/contact.html#ml
_______________________________________________
Help us build a comprehensive ClamAV guide:
https://github.com/vrtadmin/clamav-faq
http://www.clamav.net/contact.html#ml
