Snort mailing list archives

Re: Unknown EK


From: Joel Esler <jesler () sourcefire com>
Date: Tue, 9 Jul 2013 15:46:30 -0400

Nathan,

FYI -- We couldn't publish the /app.jar or /cm2.jar rules.  We had a bunch
of falses as soon as we tested them.


On Tue, Jul 2, 2013 at 6:42 PM, Community Proposed <lists () packetmail net>wrote:

Unknown malvertising EK campaign isolated with 205.185.158.219 and
205.185.158.220 which pDNS shows pointed only to piksmedia.com and
clearmetric.net respectively.  The PCRE produces a few benign false
positives,
considering the cost/risk the PCRE is worth it.  Might be able to get away
with
some proxy blocks on this one.  Popular hosts such as BBC are being used.

Global Hosts identified:
*.piksmedia.com
*.clearmetric.net
205.185.158.219
205.185.158.220

Global URLs identified:
*/app.jar
*/cm2.jar

RegEx:
regex((?-i)http:\/\/[^\x2f]+\/[a-z]{1,6}\d?\/[a-f0-9]{8,10}\.htm$)
 Unknown EK
initial landing and stage-1

Validation, as well as hits, after expansion and contraction of search
criteria
for this campaign :

select date_time, http_status, media_type, url_body_size, dest_ip, url,
url_referrer, user_agent
from webwasher_full where day>='2013-06-01' and http_status <> '407' and
(url rlike 'http:\\/\\/[^\\x2f]+\\/[a-z]{1,6}\\d?\\/[a-f0-9]{8}\\.htm$' or
url
like '%/app.jar' or url like '%/cm2.jar' or dest_ip like '205.185.158.219'
or
dest_ip like '205.185.158.220');

{See attached Unknown_EK.tsv please note HTTP Referers and UAs}

PCRE Validation
select date_time, http_status, media_type, url_body_size, dest_ip, url,
url_referrer, user_agent
from webwasher_full where day>='2013-06-01' and http_status <> '407' and
(url rlike 'http:\\/\\/[^\\x2f]+\\/[a-z]{1,6}\\d?\\/[a-f0-9]{8}\\.htm$');

{See attached PCRE_Validation.tsv please note HTTP Referers and UAs}

Looking at the PCAP {see attached} this signature may be good to match the
payload, but these signatures are untested and I am coming off a long day
and
my eyes are shot.  They may need some TLC:

alert tcp $EXTERNAL_NET $HTTP_PORTS -> $HOME_NET any (msg:"VRT COMMUNITY
Unknown Malvertising Exploit Kit Hostile Jar pipe.class";
flow:established,from_server;
file_data; content:"PK"; depth:0;
content:"|00|pipe.class"; fast_pattern; distance:0;
content:"|00|inc.class"; distance:0;
content:"|00|fdp.class"; distance:0;
classtype:trojan-activity; sid:x; rev:1;)

alert tcp $EXTERNAL_NET $HTTP_PORTS -> $HOME_NET any (msg:"VRT COMMUNITY
Unknown Malvertising Exploit Kit stage-1 redirect";
flow:established,from_server;
content:"<html><body><script>|0a|var "; fast_pattern;
content;"document.createElement("; within:80;
content:".setAttribute(|22|archive|22|, "; within:65;
content:".setAttribute(|22|codebase|22|, "; within:65;
content:".setAttribute(|22|id|22|, "; within:65;
content:".setAttribute(|22|code|22|, "; within:65;
content:"|22|)|3b 0a|document.body.appendChild("; within:65;
content:"</script>|0a|</body>|0a|</html>|0a 0a|";
classtype:trojan-activity; sid:x; rev:1;)

alert tcp $HOME_NET any -> $EXTERNAL_NET $HTTP_PORTS (msg:"VRT COMMUNITY
Unknown Malvertising Exploit Kit Hostile Jar app.jar";
flow:established,to_server;
content:"/app.jar"; http_uri;
content:") Java/"; http_header;
classtype:trojan-activity; sid:x; rev:1;)

alert tcp $HOME_NET any -> $EXTERNAL_NET $HTTP_PORTS (msg:"VRT COMMUNITY
Unknown Malvertising Exploit Kit Hostile Jar cm2.jar";
flow:established,to_server;
content:"/cm2.jar"; http_uri;
content:") Java/"; http_header;
classtype:trojan-activity; sid:x; rev:1;)

Cheers,
Nathan




-- 
Joel Esler
Senior Research Engineer, VRT
OpenSource Community Manager
Sourcefire
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