Mapping the Internet and Intranets Steve Branigan Hal

Mapping the Internet and Intranets Steve Branigan, Hal Burch, Bill Cheswick ches@lumeta. com 120 slides

Motivations • Intranets are out of control – Always have been • Highlands “day after” scenario • Internet tomography • Curiosity about size and growth of the Internet • Same tools are useful • Panix DOS attacks – a way to trace anonymous packets back! for understanding any large network, including intranets Mapping the Internet and intranets slide 2 of 120

The Original Project • Long term reliable collection of Internet and Lucent connectivity information – without annoying too many people – movie of Internet growth! • Develop tools to probe intranets • Extended database for researchers • Attempt some simple visualizations of the data Mapping the Internet and intranets slide 3 of 120

Uses for the Internet data • topography studies • long-term routing studies • publicly available database – (“open source”) for spooks • interesting database for graph theorists • combine with other mappers to make an actual map of the Internet Mapping the Internet and intranets slide 4 of 120

History of the Project • Started in August 1998 at Bell Labs • April-June 1999: Yugoslavia mapping • July 2000: first customer intranet scanned • Sept. 2000: spun off Lumeta from Lucent/Bell Labs • June 2002: “B” round funding completed Mapping the Internet and intranets slide 5 of 120

Related Work • See Martin Dodge’s cyber geography page • MIDS - John Quarterman • CAIDA - kc claffy • Mercator • Enter “internet map” in your search engine Mapping the Internet and intranets slide 6 of 120

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Methods - data collection • Single reliable host connected at the company perimeter • Daily full scan of Lucent • Daily partial scan of Internet, monthly full scan • One line of text per network scanned – Unix tools Mapping the Internet and intranets slide 9 of 120

Methods - network scanning • Obtain master network list – network lists from Merit, RIPE, APNIC, etc. – BGP data or routing data from customers – hand-assembled list of Yugoslavia/Bosnia • Run a traceroute-style scan towards each network • Stop on error, completion, no data – Keep the natives happy Mapping the Internet and intranets slide 10 of 120

Daily database • 100 -200 MB of text • compresses to 5 -10 MB • daily Internet results available from mapping web page – have not checked to see who gets it! • Saved to different partition, and offloaded to other secure computer Mapping the Internet and intranets slide 11 of 120

Traceroute • Probes toward each target network with increasing TTL • Probes are ICMP, UDP, TCP to port 80, 25, 139, etc. • Some people block UDP, others ICMP Mapping the Internet and intranets slide 12 of 120

Traceroute Client Hop 1 Hop 2 Hop 3 Router IP IP Hardware Application level TCP/UDP Hop 3 Hop 4 Server Application level Router IP IP IP Hardware Mapping the Internet and intranets TCP/UDP slide 13 of 120

Send a packet with a TTL of 1… Client Hop 1 Hop 2 Hop 3 Router IP IP Hardware Application level TCP/UDP Hop 3 Hop 4 Server Application level Router IP IP IP Hardware Mapping the Internet and intranets TCP/UDP slide 14 of 120

…and we get the death notice from the first hop Client Hop 1 Hop 2 Hop 3 Router IP IP Hardware Application level TCP/UDP Hop 3 Hop 4 Server Application level Router IP IP IP Hardware Mapping the Internet and intranets TCP/UDP slide 15 of 120

Send a packet with a TTL of 2… Client Hop 1 Hop 2 Hop 3 Router IP IP Hardware Application level TCP/UDP Hop 3 Hop 4 Server Application level Router IP IP IP Hardware Mapping the Internet and intranets TCP/UDP slide 16 of 120

… and so on … Client Hop 1 Hop 2 Hop 3 Router IP IP Hardware Application level TCP/UDP Hop 3 Hop 4 Server Application level Router IP IP IP Hardware Mapping the Internet and intranets TCP/UDP slide 17 of 120

Advantages • We don’t need access (I. e. SNMP) to the routers • It’s very fast • Standard Internet tool: it doesn’t break things • Insignificant load on the routers • Not likely to show up on IDS reports • We can probe with many packet types Mapping the Internet and intranets slide 18 of 120

Limitations • Outgoing paths only • View is from scanning host only • Takes a while to collect alternating paths • Gentle mapping means missed endpoints • Imputes non-existent links Mapping the Internet and intranets slide 19 of 120

The data can go either way B C D A E F Mapping the Internet and intranets slide 20 of 120

The data can go either way B C D A E F Mapping the Internet and intranets slide 21 of 120

But our test packets only go part of the way B C D A E F Mapping the Internet and intranets slide 22 of 120

We record the hop… B C D A E F Mapping the Internet and intranets slide 23 of 120

The next probe happens to go the other way B C D A E F Mapping the Internet and intranets slide 24 of 120

…and we record the other hop… B C D A E F Mapping the Internet and intranets slide 25 of 120

We’ve imputed a link that doesn’t exist B C D A E F Mapping the Internet and intranets slide 26 of 120

Remediations • Alternate routes not a factor on intranets • Scan from several sources • “stitching” needed – Traceroute in different directions gives different interface IP addresses – Techniques needed to link multiple IP addresses to a single host machine Mapping the Internet and intranets slide 27 of 120

Network scanning • Custom program • Concurrently scans towards 500 nets at once • Throttled to 400 packets/sec – 100 p/s over dialup modems! • Slow daily scan for host on destination network Mapping the Internet and intranets slide 28 of 120

Data collection complaints • Australian parliament was the first to complain • List of whiners (25 nets) • Military noticed immediately – Steve Northcutt – arrangements/warnings to DISA and CERT Mapping the Internet and intranets slide 29 of 120

Visualization goals • make a map – show interesting features – debug our database and collection methods – hard to fold up • geography doesn’t matter • use colors to show further meaning Mapping the Internet and intranets slide 30 of 120

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Colored by AS number Mapping the Internet and intranets slide 33 of 120

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Map Coloring • distance from test host • IP address – shows communities • Geographical (by TLD) • ISPs • future – timing, firewalls, LSRR blocks Mapping the Internet and intranets slide 51 of 120

Colored by IP address! Mapping the Internet and intranets slide 52 of 120

Colored by geography Mapping the Internet and intranets slide 53 of 120

Colored by ISP Mapping the Internet and intranets slide 54 of 120

Colored by distance from scanning host Mapping the Internet and intranets slide 55 of 120

US military reached by ICMP ping Mapping the Internet and intranets slide 56 of 120

US military networks reached by UDP Mapping the Internet and intranets slide 57 of 120

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Yugoslavia An unclassified peek at a new battlefield 120 slides

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Un film par Steve “Hollywood” Branigan. . . 120 slides

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fin 120 slides

NYC after 9/11 120 slides

CIDR and IP Counts Mapping the Internet and intranets slide 66 of 120

Routers in New York City Mapping the Internet and intranets slide 67 of 120

Internet before 9/11/2001 Mapping the Internet and intranets slide 68 of 120

Internet after 9/11/2001 Mapping the Internet and intranets slide 69 of 120

Let’s look at some intranets 120 slides

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Anything large enough to be called an “intranet” is out of control 120 slides

This is not the fault of network administrators! • Robust internet design frustrates central control – Ad hoc growth – Mergers and acquisitions frustrate long-term network planning and policies • CIOs and auditors already know this Mapping the Internet and intranets slide 78 of 120

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We call these “routing leaks” • Easily-found holes in the intranet perimeter • Show up nicely on the maps • Leaking hosts or routers announce routes to other networks or the Internet • Sometimes left over from an old corporate split • Non-functional VPNs can show up Mapping the Internet and intranets slide 83 of 120

This was Supposed To be a VPN Mapping the Internet and intranets slide 84 of 120

The maps are useful, but not the main data • We collect tens of megabytes of network data • There were unexpected subtleties to this process • How do you display all this information, given that different clients want different data? Mapping the Internet and intranets slide 85 of 120

The second technology: host leak detection • Developed to find hosts that have access to both intranet and Internet • Or across any privilege boundary • Leaking hosts do not route between the networks • May be a dual-homed host • Not always a bad thing • Technology didn’t exist to find these Mapping the Internet and intranets slide 86 of 120

Possible host leaks • Miss-configured telecommuters connecting remotely • VPNs that are broken • DMZ hosts with too much access • Business partner networks • Internet connections by rogue managers • Modem links to ISPs Mapping the Internet and intranets slide 87 of 120

Leak results • Found home web businesses • At least two clients have tapped leaks – One made front page news Mapping the Internet and intranets slide 88 of 120

Leak Detection Prerequisites • List of potential leakers: obtained by census • Access to intranet • Simultaneous availability of a “mitt” Mapping the Internet and intranets slide 89 of 120

Leak Detection Layout mitt D Mapping host A Internet intranet • Mapping host with address A is connected to the intranet • Mitt with address D has Internet access • Mapping host and C B Test host mitt are currently the same host, with two interfaces Mapping the Internet and intranets slide 90 of 120

Leak Detection mitt D Mapping host A • Test host has known address B on the intranet • It was found via Internet intranet census • We are testing for C B Test host unauthorized access to the Internet, possibly through a different address, C Mapping the Internet and intranets slide 91 of 120

Leak Detection mitt D Mapping host A • A sends packet to B, with spoofed return address of D • If B can, it will reply Internet intranet C to D with a response, possibly through a different interface B Test host Mapping the Internet and intranets slide 92 of 120

Leak Detection mitt D Mapping host A • Packet must be crafted so the response won’t be permitted through the firewall • A variety of packet types Internet intranet and responses are used • Either inside or outside address may be discovered • Packet is labeled so we C B know where it came from Test host Mapping the Internet and intranets slide 93 of 120

Leak Detection mitt D Mapping host A • This describes outbound leaks • Inbound leaks are Internet intranet C usually much more serious B Test host Mapping the Internet and intranets slide 94 of 120

Possible problems • NAT • egress filtering • transit of sensitive data over the public networks Mapping the Internet and intranets slide 95 of 120

Our new tools give new views of intranets • The pictures are mostly for management • Maps can show progress – red is bad, blue is good – we can color the maps in many ways • The real value in the reports is the list of anomalies – network leaks, routing loops, open routers, etc. Mapping the Internet and intranets slide 96 of 120

How we scan • Via dialup, using RAS servers • Secure tunnel, if you prefer – IP/SEC – PPTP – others? Mapping the Internet and intranets slide 97 of 120

What we do • Probe the network for things not in the official list • Run a host enumeration • Run leak tests on each host found Mapping the Internet and intranets slide 98 of 120

Technology used • Traceroute • SNMP queries – Router type – Routing tables • Pings • Special leak detection probes – ICMP – UDP – Other possible if requested Mapping the Internet and intranets slide 99 of 120

Report • HTML-based • Delivered on CDROM or DVD • Maps • Executive summary shows highpoints • Interactive map viewer tool for Windows Mapping the Internet and intranets slide 100 of 120

Competitors? • Not yet, not quite – Many use the same terms, but offer different services • Some components are pretty easy and free – Host enumeration – But we do it better (!) • A bit like HP Open. View – Open. View doesn’t scale – Much slower Mapping the Internet and intranets slide 101 of 120

Value • Discovers unknown parts of the network • Data feeds into existing tools, enhancing their value • You can’t secure what you don’t know about • Due diligence for intranets – Insurance? • M&A activity • Personnel turnover leaves legacy connections • Business partners Mapping the Internet and intranets slide 102 of 120

Getting a report • Web-based • We can send you a CD-ROM • You can access a web server – Free. BSD-based – One-time password authentication – Very paranoid server Mapping the Internet and intranets slide 103 of 120