WebKnock.org: An fwknop SPA web-interface
Vasilis Mavroudis has launched WebKnock.org, a web-based front end to the fwknop (Single Packet Authorization) client. It does not yet seem to support the full suite of fwknop features, but the WebKnock site allows you to send basic auth packets to your fwknop server in order to open firewall ports. This can definitely come in handy if you need access to a port on your server, and don’t have the fwknop client handy on the computer, Android or iPhone (coming soon).
Note that although WebKnock uses SSL to protect the HTTP session, you are required to supply your fwknop password. If logged or intercepted, your knock details could be used to open firewall ports or even run commands on your server (depending on how you’ve configured fwknop). While WebKnock may be useful in a bind, from a purely security standpoint I don’t recommend using it regularly due to this risk. If you do use it, you should consider changing your fwknop passphrase.
I hope that WebKnock is eventually open-sourced to allow both for the code to be reviewed, and for people to host their own instance of WebKnock. It would also be nice to see more fwknop features being added, including the ability to define a username, and open multiple ports at once (eg. by entering: tcp/22 udp/53 tcp/80). The ‘Allow IP’ field should also get pre-populated with the visitor’s IP address for convenience.
Source: Cipherdyne
Reverse SSH over Tor on the Pwnie Express
The Pwnie Express (PwnPlug) is a great little tool for hackers, pentesters and social engineers alike. While I don’t advocate the use of a Pwnie for illicit purposes, I was intrigued about using it as an untraceable tap into a network. Out of the box the Pwnie allows you to configure reverse SSH connections, exfiltrated over a number of different protocols including HTTP, SSL, ICMP and DNS.
While these are great for getting out of controlled networks, they all require the Pwnie to be configured with the IP address of your SSH server, which could potentially be traced back to you. It also requires your SSH server to be able to directly receive connections at the IP/hostname configured on the Pwnie. While one could run an SSH server on a proxy box somewhere, I felt that was too primitive, so I installed Tor on my Pwnie and configured a Tor Hidden Service on my SSH server.
Note: For the purposes of this tutorial, the SSH server will be running on BackTrack 5. I’m assuming you’ve already performed the initial Pwnie Express setup steps on the server! Check out my PwnieScripts to help speed up and automate the Pwnie setup.
These instructions do not yet work on Pwn Plug software >= 1.1 as they’ve changed the layout of things! Will update this post when I get the time.
Kernel.org Compromised, OpenSSH Source Not Backdoored
Kernel.org, the primary site for the Linux kernel source, was compromised sometime in August. It is believed that the attackers gained access using compromised user credentials, and then escalated their privileges to root. Early pieces of information implied that some OpenSSH source code was stored on the compromised Kernel.org server(s), apparently this may not be the case. So far the investigation has found that several modifications were made to the compiled OpenSSH client and server binaries running on the system to log user activity. The full extent of the changes is not yet known, and nobody has yet come forward to claim this hack.
If you’ve installed or updated your kernel or OpenSSH recently, you may want to reinstall from a known good version, although it is not yet known if any kernel sources were modified. Although in this case OpenSSH wasn’t compromised, admins can consider running some form of Single Packet Authorization, such as fwknop, as an additional layer of protection for your SSH server against these kinds of issues (backdoors) and other potential future 0days.
Hopefully more info will come to light as the investigation progresses. Hit the jump for more details.
Locate Lost or Stolen Macs with ‘Find My Mac’ in Lion and iCloud
Apple’s popular Find My iPhone feature of MobileMe is being extended to Macs as well, as part of iCloud and Lion (10.7.2). It will also allow the person who found or stole the machine to login using a limited guest account (with only access to Safari), in order to allow your Mac to connect to the internet. As with the iOS version, Find My Mac will allow you to remotely send a message, lock or even wipe your computer.
I’m guessing the geolocation will be limited to triangulating local wireless networks, but I’m hoping it will also send back the public IP address of the network it’s currently connected to, which would help significantly when trying to recover a stolen device. I wonder how developers of commercial Mac tracking software are feeling right about now?
For more info and pictures check out this post at Cult of Mac. In other news, iOS 5 will finally bring the ability to delete entries from your call history.
Fwknop in BackTrack 5 Repository
Just a quick update to say that fwknop (Single Packet Authorization tool) has made it into the BackTrack 5 repository. Although it’s not installed by default, it’s a few keystrokes away, and can be installed by typing the following into the terminal:
apt-get install fwknop-client
apt-get install fwknop-server (if you want to use the server on your BackTrack install)
Note that it’s still version 1.9.12 of the Perl implementation, as the the C++ port (v 2.0) is still in the Release Candidate stage. Those of you who have been meaning to experiment with Single Packet Authorization and have already downloaded BT5, now’s a good time to install fwknop and give it a try! When installing fwknop-server it brings up an ultra-simple config screen that allows you to set up your initial passphrase.
Read more
Single Packet Authorization with simpleSPA
I was just made aware of simpleSPA, a recently-released Java implementation of Single Packet Authorization by Chris Chrysler. The package provides a Linux-only server-side daemon, and a Linux and Windows client. Although I haven’t testing it yet, I assume the client will also work on Mac OS X. This implementation requires a Linux server as it relies on iptables being the firewall. simpleSPA uses two RSA keys in order to encrypt the authentication information. The first key encrypts the username of the user requesting access, while the second key is used to encrypt a pre-shared key and a timestamp (for freshness). The resulting authorization packet is then sent via UDP to the server. Although a timestamp is used, there doesn’t appear to be an explicit check for previously-received packets (ie. using a hash), so there may be some for time-limited replay attacks. Because RSA and public-keys are used, it’s a shame to see that it doesn’t use digital signatures to protect the payload.
simpleSPA does not allow for dynamic configuration of the firewall. As such, upon receiving a valid authorization packet (using Jpcap to sniff the wire), the server looks at a pre-defined config file that defines the firewall port(s) to be opened for the requesting user. Furthermore the port is opened for the IP that made the request, thus not allowing the client to embed an IP within the request and open a port out-of-band. The author states that this implementation is primarily an academic proof-of-concept at this point, and so is nowhere near as complete as other implementations such as fwknop (Perl/C) and Aldaba (C). It is nice, however, to see continued research and development into SPA as well as a Java implementation!
OpenBSD IPSec Possibly Probably Not Backdoored by FBI
In a post to the OpenBSD mailing list, developer Theo de Raadt reveals an email from an ex-contributor (Gregory Perry) alleging that money was accepted from the FBI around 2000-2001, in return for implementing a backdoor into the IPSec stack. Such a backdoor would give the FBI the ability to eavesdrop on any IPSec connection made using OpenBSD, or any other projects that have since made use of its IPSec code.
Clearly this would be a big deal if true, and although we know that open source projects are regularly backdoored by rogue developers or ‘hackers’ (such as the recent ProFTPd backdoor), it is not often that we hear of governments inserting some themselves. Should we be surprised? After all it is known that the NSA was involved with the development of DES by altering the algorithm’s S-Boxes and suggesting a shorter key length. There are also rumors of a covert backdoor in several versions of the Windows OS. That said, many people are smelling a troll in this case.
Following this information (can we call it a leak rumor?), OpenBSD’s IPSec code will undoubtedly come under quite a bit of scrutiny, and I’m sure we will hear a lot more about it should anything untoward be uncovered.
Read the full mailing list post here, archived below for posterity.
[Update] Scott Lowe denies being affiliated with the FBI, and Jason Wright denies having inserted a backdoor. This is sounding more and more like a trolling. To what end, I couldn’t speculate. It’s also worth noting that this kind of activity would probably not fall under a normal NDA, but under a government-level Top Secret classification which lasts at least 25 years…
An interesting observation about OpenBSD IPSec and Stuxnet. Read more
ProFTPD 1.3.3c Briefly Backdoored by Hackers
Servers of the widely popular FTP server, ProFTPD, were compromised (probably with 0day) on the 28th of November 2010. During the attack, some source code was modified to insert a backdoor. The source files affected were for ProFTPD version 1.3.3c., between the 28/11/2010 and 02/12/2010.
The backdoor introduced by the attackers allows unauthenticated users remote root access to systems which run the maliciously modified version of the ProFTPD daemon.
If you installed or updated ProFTPD from one of the official mirrors during that time, it is recommended that you recompile from a known good version of the code. The source modification was spotted and rectified on 01/12/2010. MD5 sums for the valid source tarballs:
8571bd78874b557e98480ed48e2df1d2 proftpd-1.3.3c.tar.bz2
4f2c554d6273b8145095837913ba9e5d proftpd-1.3.3c.tar.gz
Hit the jump for details on how the backdoor is triggered. A Metasploit module is available to automate the exploit. Read more
Wikileaks Releases 250k US Embassy Cables (Chinese Gov’t Responsible for Google Attacks)
Wikileaks, who are currently the target of a massive DDoS attack, has just released 251,287 leaked US embassy cables (dubbed Cablegate). Mirrors available here.
The cables, which date from 1966 up until the end of February this year, contain confidential communications between 274 embassies in countries throughout the world and the State Department in Washington DC. 15,652 of the cables are classified Secret.
The embassy cables will be released in stages over the next few months. The subject matter of these cables is of such importance, and the geographical spread so broad, that to do otherwise would not do this material justice.
The cables show the extent of US spying on its allies and the UN; turning a blind eye to corruption and human rights abuse in “client states”; backroom deals with supposedly neutral countries; lobbying for US corporations; and the measures US diplomats take to advance those who have access to them.
One cable reveals that China’s Politbureau was responsible for the attacks against Google China back in January 2010.
[Update] A torrent is available to download the entire Cablegate site in a single archive for your personal reading pleasure (magnet links).
Pauldotcom Episode 221 – Talking Single Packet Authorization
Episode 221 of Pauldotcom Security Weekly is available for download. In it I give a tech segment about Single Packet Authorization, briefly describe how to configure your firewall and use fwknop to dynamically open ports.
The podcast is available on iTunes, and by direct download. Check out the show notes for full details. Thanks for having me on the show guys!
Here is a short video of fwknop in action:
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