Security Incidents mailing list archives
Re: ICMP/SYN Flood
From: "CTA" <dnsadmin () INTRAMEDX COM>
Date: Thu, 22 May 2003 15:31:55 -0400
Looks like your ISP has an open router. If its a CISCO be sure that they have the basics set: no ip directed-broadcast no ip source-route no cdp running no cdp enable no service tcp-small-servers no service udp-small-servers no service finger no ip bootp server no ip http server Also, they should have basic Anti-Spoofing Access List Filter set to drop and log, and Ingress Filters to stop untrusted internal hosts. On 22 May 2003, at 7:47, Muhammad Naseer Bhatti wrote:
Hi list .. I am experiencing a bad DDoS attack toward one of my server. The attack is pointed to only 1 IP on which a governmental site is hosted. Seems some folks don't like the site to stay up. As far as the Server (Linux) security is concerned, I am able to make that up serving all requests without any hesitation. My network with which I am connected to is poorly configured and allowing the DDoS attack to pass thru their routers. I am getting two kind of attacks here: - ICMP Flood Simple ICMP flood from various spoofed hosts. This I know can be blocked on the router for the particular IP. Unfortunately the network guys are still not able to do that. - SYN Flood Interesting thing. Loots of SYN requests from these kind of network/broadcasts towards port 80 only. 37.72.0.0 128.89.0.0 173.66.0.0 37.155.0.0 177.225.0.0 37.94.0.0 36.162.0.0 117.77.0.0 151.162.0.0 36.216.0.0 134.248.0.0 175.129.0.0 And the list goes oon .. The question I want to ask here, is the network/router poorly configured at my NOC which is allowing broadcasts/networks to pass through it? If so, how can I assist them to fix it? I am not a Cisco guru, so might need someone to give me some hints so that I can pass that to the poor NOC techs. Any help would be appreciated. Thanks, Muhammad Naseer
- - **************************************************** Bernie Chief Technology Architect Chief Security Officer cta () hcsin net Euclidean Systems, Inc. ******************************************************* // "There is no expedient to which a man will not go // to avoid the pure labor of honest thinking." // Honest thought, the real business capital. // Observe> Think> Plan> Think> Do> Think> ******************************************************* ---------------------------------------------------------------------------- *** Wireless LAN Policies for Security & Management - NEW White Paper *** Just like wired networks, wireless LANs require network security policies that are enforced to protect WLANs from known vulnerabilities and threats. Learn to design, implement and enforce WLAN security policies to lockdown enterprise WLANs. To get your FREE white paper visit us at: http://www.securityfocus.com/AirDefense-incidents ----------------------------------------------------------------------------
Current thread:
- ICMP/SYN Flood Muhammad Naseer Bhatti (May 22)
- RE: ICMP/SYN Flood David Gillett (May 23)
- Re: ICMP/SYN Flood Sebastian Jaenicke (May 23)
- Re: ICMP/SYN Flood CTA (May 23)
- Re: ICMP/SYN Flood Dr J (May 23)
- <Possible follow-ups>
- Re: ICMP/SYN Flood Muhammad Naseer Bhatti (May 23)
- RE: ICMP/SYN Flood Whiteside, Larry [contractor] (May 23)