IDS mailing list archives
Re: ssh and ids
From: Adam Powers <apowers () lancope com>
Date: Tue, 22 Jun 2004 09:56:47 -0400
Regarding: "Hacker busts into your network and sets up an SSH server, RNA picks it up and can let you know that it detected a new service and logs the flow data, etc." But you can't stop with simple "port profiling". StealthWatch has had this technology for years and we've found that the same problems you run into with IDS alerting is seen when attempting to truly profile and react to each new service entering the network. StealthWatch even takes it a step further and allows you profile outbound "client" traffic if you wish (in addition to server ports). Still, this is a classic "needle in a haystack" problem. Sure, the data that identifies the attack is there, but it's useless because you can't find it. Port profiling has to be augmented with other more intelligent techniques to expose the important data. Sure, StealthWatch can be configured to alarm when a new port shows up, but the real power of the port profiling is seen during the flow analysis process. StealthWatch uses the port profile data to determine how network traffic should be analyzed. An example includes a DNS related ICMP Port Unreachables. When StealthWatch recognizes a host as being a DNS server, it immediately begins applying flow analysis algorithms that are suitable for analysis of DNS traffic. The algorithms expect large numbers of small packet, many of which will elicit ICMP type 3 code 3 responses from the client resolver (Windows 2000's resolver often sends 2 or more packets from the same source port to different servers, causing both servers to respond; one packet gets used to fulfill the query, the second packet get rejected with a Port Unreachable). Without port profiling data, StealthWatch would misconstrue the Port Unreachables as UDP scanning behavior. On 6/18/04 8:53 PM, "Martin Roesch" <roesch () sourcefire com> wrote:
Hey Mark, VENDOR ALERT: I'm a vendor and I'm going to talk about my technology. Please take my comments with an appropriate amount of sodium chloride. Sourcefire's RNA product is capable of isolating/identifying layer-7 protocols (including encrypted protocols) and tracking the flows. For example, if you wanted to find SSH/SSL traffic that it being initiated from outside your network to inside, setting up a query (or automated reporting) is pretty trivial. Hacker busts into your network and sets up an SSH server, RNA picks it up and can let you know that it detected a new service and logs the flow data, etc. Anyway, if you're interested in seeing a demo or talking more, let me know. As far as IDS being able to do much with encrypted traffic, there's generally not much to do once the session goes encrypted. You can setup rules in a system like Snort to differentiate between "allowed" and "everyone else" hosts talking to machines on your network pretty easily (and you can query RNA's flow data for the info too). I know the NAI guys just released a mod to their sensors that allow them to do real-time SSL decryption if you're willing to escrow the private crypto keys on the box (shudder). There's been talk of implementing the same sort of thing in Snort (ala ssldump) for a while, but it's never come together... -Marty On Jun 18, 2004, at 2:18 PM, Runion Mark A FGA DOIM WEBMASTER(ctr) wrote:Lets suppose the attacker is mildly sophisticated, and after making the initial assault roots the box and installs a secure backdoor or two. Is there any IDS capable of isolating data it cannot read, except to monitor authorized port usage of a system or group of systems? Not to complicate the question, but when the attacker is using portal gates and all communications traffic is encrypted in normal channels how can an IDS participate? Monitoring normal traffic patterns seems a bit slow for detection. - Mark Runion ----------------------------------------------------------------------- ---- ----------------------------------------------------------------------- ----
-- Adam Powers Senior Security Engineer Advanced Technology Group c. 678.725.1028 o. 770.225.6521 f. 770.225.6501 e. apowers () lancope com AOL IM: adampowers22 StealthWatch by Lancope - Security through network intelligenceĀ --------------------------------------------------------------------------- ---------------------------------------------------------------------------
Current thread:
- ssh and ids Runion Mark A FGA DOIM WEBMASTER(ctr) (Jun 18)
- Re: ssh and ids Adam Powers (Jun 21)
- Re: ssh and ids Martin Roesch (Jun 21)
- Re: ssh and ids Tony Carter (Jun 22)
- Re: ssh and ids Jason (Jun 22)
- Re: ssh and ids Adam Powers (Jun 22)
- Re: ssh and ids Martin Roesch (Jun 23)
- Re: ssh and ids Christian Kreibich (Jun 24)
- Re: ssh and ids Gary Flynn (Jun 21)
- Re: ssh and ids Frank Knobbe (Jun 22)
- Re: ssh and ids Bamm Visscher (Jun 23)
- Re: ssh and ids Frank Knobbe (Jun 23)
- Re: ssh and ids Frank Knobbe (Jun 22)
- <Possible follow-ups>
- Re: ssh and ids Ron Gula (Jun 21)
- RE: ssh and ids Wozny, Scott (US - New York) (Jun 21)
- RE: ssh and ids Omar Herrera (Jun 21)
- RE: ssh and ids Matthew F. Caldwell (Jun 22)