It occurred to me today…how ’bout trying an IPcomp scenario? Of course, looking at RFC 3173, I was very excited about running a test and actually viewing Next Header / Protocol = 108, as the IETF guys say.

Basically, the “Compression” part of this IPsec traffic is negotiated just as  any other protocol: AH, ESP, EAP…via IKE, or manually configured on a device. Now…as I’ve got to devices….good question: _what_ device could I use if I want IPsec IPCompression?

Look at this: http://www.vpnc.org/vpnc-ipsec-features-chart.html. Scroll down to “Features (HTML table). The vendors that actually implement this, as per VPN Consortium (and for some of them I could tell you from direct experience), are CheckPoint, Cisco, McAfee, SafeNet, StoneSF and TeamF1. A bit disappointed that I didn’t have the opportunity of working on all of these devices, I am redirecting my attention to what I do have: a big, shiny and fluffy Debian, with Strongswan installed and xfrm module also on.

So, lets get down to business. I have taken the simplest scenario I could think of at the moment, a transport mode scenario, having as Initiator 192.168.0.10 and as Responder 192.168.0.1. These two hosts negotiate 3des-md5-dh2 algorithms, doing PSK authentication. No PFS, no other kinky stuff. Just basic IKEv2 negotiation. The Strongswan config is as simple as possible.

*Note 1 : on strongswan.org people say that IKEv2 does not support compression – I have run a test with IKEv2 and compression and it works very well But, in order to humor the strongswan guys, I have used IKEv1 in the following scenario

*Note 2 : in order to actually _see_ the encapsulated packets, I have used ESP-NULL Encryption for data encapsulation. Yes, I could have used a NetCocoon analyzer, but that – in the next episode

So: IKEv1, Transport mode, Main Mode, Null Encryption, ESP only, IP Comp:

# ipsec status

000 “network1″: 192.168.0.1[192.168.0.1]…192.168.0.10[192.168.0.10]; erouted; eroute owner: #3

000 “network1″:   newest ISAKMP SA: #2; newest IPsec SA: #3;

000

000 #3: “network1″ STATE_QUICK_R2 (IPsec SA established); EVENT_SA_REPLACE in 2488s; newest IPSEC; eroute owner

000 #3: “network1″ esp.525b0b48@192.168.0.10 (0 bytes) esp.5511d8c2@192.168.0.1 (0 bytes) comp.1169@192.168.0.10 comp.527e@192.168.0.1; transport

000 #2: “network1″ STATE_MAIN_R3 (sent MR3, ISAKMP SA established); EVENT_SA_REPLACE in 2488s; newest ISAKMP

000

Yes, it worked.

Now…I am not sure what exact compression algorithms this Strongswan daemon has, but I can tell you for sure it uses at least DEFLATE (  RFC 2394 ). Cisco on the other hand, uses only LZS (RFC 2395 ) – as far as I have seen – to be updated if anybody else tested it versus DEFLATE.

The process of actually obtaining this cute ESP packets is the following:

a. get the Data from the upper layers of the TCP stack – doh, we need data

b. compress the Data above using the chosen algorithm – you will notice the CPI – Compression Parameter Index – which has well know identifiers for the well known compression algorithms

c. set the Next Header value of the IPComp header to the layer 4 protocol (in this case, TCP)

d. encapsulate everything in ESP, put on the corresponding SPI, set the Next Header value of the ESP header to 108 (0×6c)

e. wrap it up in IP and… we are all set

— You can admire the ESP of IKEv1 in the screenshot attached

Now, what happens differently with IKEv2? I was telling you before the on Strongswan, IKEv2 and AH is a no-no for the moment, ESP with null encryption does a weird thinggie that vmp was so kind to point it out for me (while I was feeling actually quite happy about myself being able to do an IPComp test via IKEv1).

The thing is that, unlike the (correct) way of doing IPComp in IKEv1 (see the aboe a. to e. steps), IKEv2 implementation of Strongswan does a weird thing:

a. get the Data ..blah-blah

b. compress the Data with whatever compression algorithm and put on the IPComp header with CPI value and all

* c. put on another IP header (the internal one, in case of a tunnel mode scenario)

d. put on the ESP header

e. wrap everything up

— Unfortunately, you CANNOT admire the ESP of IKEV2 in a screenshot, because my current wireshark has no idea on how to do decompression of this type of packet. Once it does, I will update

Tags: checkpoint, cisco, compression, Debian, IETF, IKE, IPComp, ipsec, netcocoon, passion, RFC, Strongswan, techie, xfrm

Recently I’ve had the opportunity of playing a bit with a CheckPoint UTM NGX R65 – ze mighty solution from the CheckPoint guys. Ignoring the obvious impediments (Romanian posts) I had when configuring the device from GUI, it left me a nice impression.

These guys are not quite the interop gurus ever, but they’ve strived to implement the crankiest drafts that ever appeared from IETF. Running this on the company I work for, interop even with this device worked well (so buy Ixia products if  you want IPsec testing ), but trying to make it work with Strongswan I’ve got into big trouble.

Why? Well, let’s take a look at the most common IPsec – IKEv1 implementations. They usually pick one/more of the following standards:

- RFC 2407

- RFC 2408

- RFC 2409

- RFC 3706 – should you like DPD – Dead Peer Detection

- RFC 3947 and RFC 3948 for NAT-T

- mode-cfg-02 draft – for the most common Mode-Configuration operations (perfectly inter-operable by Cisco, Juniper’s ScreenOS, Strongswan, Sonicwall, Stoke and Clavister) – as you may have guessed, NO, NOT with CheckPoint

- draft-beaulieu-ike-xauth-02 – for xAuth authentication of clients – inter-operable on Cisco, NetScreen, Stoke and Sonicwall (not sure about Clavister – haven’t tried it yet) – and, yes, not on CheckPoint

As a nice old guy would say: “Security through obscurity” , not quite my favorite idea of _security_. Still, a good to follow idea for CheckPoint. Why? Because, even though they implement the RFC 2407, 2408 and 2409, they have decided not to implement the most common xAuth draft (presented above), feeling that symmetrical authentication is just too lame, so they have implemented draft-zegman-ike-hybrid-auth-01, which defines how to do uni-directional independent authentication on the remote-access scenarios – procedure enforced by the CheckPoint VPN Client (only, if you ask me, though I haven’t tried too many others).

Once you bypass this authentication procedure, configuring the UTM to authenticate the clients using X.509 certificates, you end up in yet another dead-end: the so-called Office-Mode, which is the CheckPoint way of saying “Mode-Configuration”, with a significant difference: the actual packet exchange is not standard. We have tried, me and my programmer fellows (by the way: thanks for enduring this by my side), to “reverse-engineer” this mighty exchange, but even with the CheckPoint debug and hacking into our friend pluto, we didn’t manage to get it right.

I have talked to a tech-support guy from CKP, a very nice person, still incapable of saying anything about their solution without first asking for permission from his PM/Management/whatever. So, up until today, I haven’t been able to pull this through. This is why the things I’m going to describe below are only ALMOST CheckPoint IPsec…

Read the rest of this entry »

Tags: checkpoint, cisco, clavister, DPD, HybridInitRSA, IETF draft, IKEv1, ipsec, mode-config, NAT-T, netscreen, NGX R65, office mode, PKI, Remote-Access, sonicwall, stoke, techie, X.509, xauth

Razvan Rughinis rules

Tags: cisco, passion, techie

Este pe 5 si 6 noiembrie, in Radisson Sas. Cum corporatia la care lucrez este unul dintre partenerii tehnologici ai evenimentului, m-am prezentat si eu la stand, sa-i lamuresc pe curiosii care intreaba de VoIP, Security, networking protocols si solutii de monitorizare si mentenanta pentru retele.

Agenda evenimentului e pe site-ul Cisco Expo 2008. Mi-a placut prezentarea, companiile – numeroase si nu prea si multa lume cunoscuta din domeniu. Din pacate, nu am ajuns la niciunul dintre workshop-uri, insa am avut ocazia sa vorbesc cu oameni interesanti. Cei mai multi au venit sa intrebe ce facem noi, ce e cu solutiile de mentenanta care impanzesc harta Norvegiei IxRAVE, colegii de la layer 2-3 le-au prezentat solutiile noastre de testare de Routing, Acces si VPN – IxNetwork, iar pe partea de layer 4-7 am prezentat solutia de SIP si RTP din IxLoad. Am observat ca suntem prea putin cunoscuti sau populari in Romania, probabil si din cauza inaccesibilitatii preturilor pe piata aceasta.

Un amanunt care mi-a colorat putin cele 6 ore petrecute la stand a fost vizita a doi reporteri atrasi de graficele colorate displayate pentru traficul de SIP si RTP QoS. Au venit sa ma intrebe despre ce este vorba in acest produs. Am inceput imediat sa explic, sa arat, sa demonstrez, sa prezint cum integram noi VoIP cu security, cum facem noi 15000 de endpointi de SIP peste tot atatea tunele IPsec…si tot asa. Dupa 5 minute in care oamenii aia se uitau dragut la mine, unul din ei imi spune politicos: “Domnisoara, noi nu cunoastem detalii tehnice, lucram pentru o televiziune, si ne-au placut graficele dumneavoastra colorate. Am putea, va rugam, sa filmam putin demo-ul acesta?”…Cred ca trebuie sa mai lucrez putin la people skills. Eh, cel putin nu au plecat, si au fost draguti sa asculte tot mambo–jumbo-ul meu imbibat cu acronime care de care mai haioase

Overall, un eveniment dragut, poate putin cam prea slab tehnic pentru gustul meu, dar o ocazie frumoasa de schimbat carti de vizita si de prezentat compania persoanelor din bransa. Pentru a doua zi, cautati feedback in alta parte, ca eu am prestat numai in prima.

Tags: cisco, fun, security, techie, voip