Snort mailing list archives
Re: Couple sigs
From: Alex Kirk <akirk () sourcefire com>
Date: Mon, 10 Sep 2012 09:52:53 -0400
With, that is, some tweaks to be slightly less specific. If you can be evaded by simply switching the order of the width and height on the first one, for example, well, you're probably less than useful. (Sorry for clogging anyone's inbox with a second mail here, it's still early on a Monday morning.) On Mon, Sep 10, 2012 at 9:49 AM, Alex Kirk <akirk () sourcefire com> wrote:
These look like solid rules, James - especially the hidden Iframe bit, that seems like suspicious practice even if it's on a "legit" web site. I'm going to have these run through our rule testing group, just in case we see legit sites doing either one of these things on a regular basis - but assuming that they come up clean, I think they'd be excellent additions to, say, INDICATOR-OBFUSCATION. On Fri, Sep 7, 2012 at 2:06 PM, James Lay <jlay () slave-tothe-box net>wrote:So...I get really tired of malicious redirects, so here are a couple sigs: Maybe hidden iframes are all over the net...maybe not, but this one is specifically designed to catch stuff like the below: alert tcp $EXTERNAL_NET $HTTP_PORTS -> $HOME_NET any (msg:"WEB-CLIENT Hidden iframe"; flow:to_client, established; file_data; content:"<iframe width=1 height=1 style=visibility|3a|hidden"; classtype:bad-unknown; sid:10000023; rev:1;) <iframe width=1 height=1 style=visibility:hidden src='http://www.redacted.com/wp-count.php?ref=redacted</iframe> this next one is to catch those pages that are just a single refresh line with a link to an IP...I see a lot of these types being pointed at from compromised (wordpess) sites...as I understand it file_data should make this sig search from the beginning of the response body...which is exactly where I want it to search and not say the middle of the page (I hope): alert tcp $EXTERNAL_NET $HTTP_PORTS -> $HOME_NET any (msg:"INDICATOR-COMPROMISE Page with only IP redirect, possible compromised site"; flow:to_client, established; file_data; content:"<html><head><meta http-equiv=|22|refresh"; pcre:"/\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}/sm"; classtype:bad-unknown; sid:10000024; rev:1;) <html><head><meta http-equiv="refresh" content="0;url=http://redacted/redacted"></meta></head></html> So far no FP's in my environment, your mileage may vary. As usual, comments, thoughts, improvements, hack & slash on these are welcome. Thanks all. James ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ Snort-sigs mailing list Snort-sigs () lists sourceforge net https://lists.sourceforge.net/lists/listinfo/snort-sigs http://www.snort.org Please visit http://blog.snort.org for the latest news about Snort!-- Alex Kirk AEGIS Program Lead Sourcefire Vulnerability Research Team +1-410-423-1937 alex.kirk () sourcefire com
-- Alex Kirk AEGIS Program Lead Sourcefire Vulnerability Research Team +1-410-423-1937 alex.kirk () sourcefire com
------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/
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Current thread:
- Couple sigs James Lay (Sep 07)
- Re: Couple sigs Alex Kirk (Sep 10)
- Re: Couple sigs Alex Kirk (Sep 10)
- Re: Couple sigs James Lay (Sep 10)
- Re: Couple sigs Alex Kirk (Sep 10)
- Re: Couple sigs James Lay (Sep 10)
- Re: Couple sigs lists () packetmail net (Sep 10)
- Re: Couple sigs Alex Kirk (Sep 10)
- Re: Couple sigs lists () packetmail net (Sep 10)
- Re: Couple sigs Alex Kirk (Sep 10)
- Re: Couple sigs Alex Kirk (Sep 10)