Snort mailing list archives
Re: lots of false positives for "GPL SQL user name buffer overflow attempt"
From: rmkml <rmkml () yahoo fr>
Date: Tue, 21 Jan 2014 15:20:24 +0100 (CET)
Hi Cyrille, Please test with this new version please: alert tcp $EXTERNAL_NET any -> $SQL_SERVERS $ORACLE_PORTS (msg:"GPL SQL user name buffer overflow attempt"; flow:to_server,established; content:"connect_data"; nocase; content:"|28|user="; nocase; isdataat:1000,relative; content:!"|22|"; within:1000; content:!"|29|"; within:1000; reference:url,www.appsecinc.com/Policy/PolicyCheck62.html; classtype:attempted-user; sid:2102650; rev:4;) Regards @Rmkml On Tue, 21 Jan 2014, Cyrille Bollu wrote:
Hi, thanks for the info I was just looking at the flow:only_stream... options. That might well be related. OTH, I'm new to snort and I don't yet understand the links between all these "official ruleset" (you mean the VRT one?), the ET, the GPL,.... Do you mind explaining me what you means by "ET forking"? Br, Cyrille On Tue, Jan 21, 2014 at 3:11 PM, Joel Esler (jesler) <jesler () cisco com> wrote: isdataat reads a whole stream, so if packets are being reassembled as part of the Stream5 preprocessor, isdataat can cross those packet boundaries, while you may only receive one packet in the alert. That may be the cause of it. It doesn?t look that rule matches the rule in the official ruleset, yet another reason why ET forking these rules was a bad idea. On Jan 21, 2014, at 8:48 AM, Cyrille Bollu <cyrille.bollu () gmail com> wrote: Hi, Signature 2102650 generates lots of false positives here. alert tcp $EXTERNAL_NET any -> $SQL_SERVERS $ORACLE_PORTS (msg:"GPL SQL user name buffer overflow attempt"; flow:to_server,established; content:"connect_data"; nocase; content:"|28|user="; nocase; isdataat:1000,relative; content:!"|22|"; within:1000; reference:url,www.appsecinc.com/Policy/PolicyCheck62.html; classtype:attempted-user; sid:2102650; rev:3;) It seems like the "isdataat:1000,relative" option is not taken into account, as packets are smaller than 1000 bytes. For example, here are the last bytes of a matching packet: "(HOST=PC-MARIANNE)(USER=marianne))))". I can provide you with a packet capture if you want Br, Cyrille
------------------------------------------------------------------------------ CenturyLink Cloud: The Leader in Enterprise Cloud Services. Learn Why More Businesses Are Choosing CenturyLink Cloud For Critical Workloads, Development Environments & Everything In Between. Get a Quote or Start a Free Trial Today. http://pubads.g.doubleclick.net/gampad/clk?id=119420431&iu=/4140/ostg.clktrk
_______________________________________________ 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!
Current thread:
- lots of false positives for "GPL SQL user name buffer overflow attempt" Cyrille Bollu (Jan 21)
- Re: lots of false positives for "GPL SQL user name buffer overflow attempt" Joel Esler (jesler) (Jan 21)
- Re: lots of false positives for "GPL SQL user name buffer overflow attempt" Cyrille Bollu (Jan 21)
- Re: lots of false positives for "GPL SQL user name buffer overflow attempt" rmkml (Jan 21)
- Re: lots of false positives for "GPL SQL user name buffer overflow attempt" Cyrille Bollu (Jan 21)
- Re: lots of false positives for "GPL SQL user name buffer overflow attempt" Joel Esler (jesler) (Jan 21)