Abstract: add SID APT source, configure APT Pinning to give squeeze packages priority over SID ones, rebuild the nodejs package under squeeze.

  • Add SID APT source by creating /etc/apt/sources.list.d/sid.list (use your nearest mirror ):
deb http://ftp.us.debian.org/debian/ sid main
deb-src http://ftp.us.debian.org/debian/ sid main
  • Configure APT pinning by creating /etc/apt/preferences.d/sid:
Package: *
Pin: release a=unstable
Pin-Priority: 50
  • Install the latest version of libv8 manually, libv8- at the time of writing this:
apt-get install libv8-
  • Download the nodejs package sources, dependencies and build them:
apt-get source nodejs
apt-get build-dep nodejs
cd nodejs-*
debuild -nc -uc
  • If you encounter build-dependency errors, you should try first to lower the dependency in debian/control, both in Build-Depends and in Depends and re-run debuild. If the build fails (e.g. with undefined reference to 'ev_run') the previous version is missing required functions. So, you must install the updated versions of the required dependencies (e.g. libev4) from sid, using apt-get install name=version e.g. libev4=1:4.11-1. I suggest this because you’ll have to manually update packages installed from sid, so the lesser, the best.

  • Install the generated package

dpkg -i nodejs_*.deb nodejs-dev*.deb
  • Profit :-)

Neo Tux

So you have a Linux VM you use for development, because you want to mirror the production environment as closely as possible. You have many applications to deal with, they have to be running at the same time because they are nifty REST JSON web services.

You are very tired to remember which one you put on port 8081, and your configuration files slowly become a real mess. So you set up IP address aliases in for the network interface and decide to assign even host names – /etc/hosts is just fine – for each app.

Then, in such a setup, why would you still need to run them on ports higher than 1024? Wouldn’t be just great to type the application name in the browser address bar? Indeed it is, but it’s better to not run them as root, anyway.

The solution are Linux capabilities (see also here ). The one that interests us is cap_net_bind_service: it gives a process the right to bind well-known ports (< 1024). If you use an interpreted language, of course you’ll have to add the capability to the interpreter itself. That’s why there’s development in the title of this article – you should not set this up on a production server, if you don’t know what you are doing.

One final quirk: if you happen to dlopen() shared objects that dynamically link towards libraries outside the canonical paths, you cannot load them via LD_LIBRARY_PATH (e.g. the SYBASE.sh) as it is ignored for setcap-ped processes. You should better move the library paths into an /etc/ld.so.conf.d snippet.


Assuming you are the latest and greatest rails developer, you should become root – or use sudo, as you wish – and

setcap cap_net_bind_service+ep `which ruby`


thin start -a yourapp -p 80
>> Using rack adapter
>> Thin web server (v1.2.11 codename Bat-Shit Crazy)
>> Maximum connections set to 1024
>> Listening on yourapp:80, CTRL+C to stop

If it is good, they stop making it”, the payoff printed on the conference necklaces, distributed to every participant, along with an über-l33t badge customized with our nickname and the key hash.

Being my first experience at an international security conf (I’ve only been to the ccc2k+7 camp), and being a ph outsider ‘cause I never participated to previous editions, the boot keynote held by FX, staffer and frontman, has been enlightening: “you ought to be here!”, he yelled while pointing at the stage, wearing a white shirt with the Phenoelit logo printed on both arms.

“This conference has never started on time”, he continued, “so there was no reason to do that for this last one”. the schedule is straightforward: party, the next days talks from 12.00PM to 7.30PM, then party, and the last days talks from 12.00PM to 5.30PM. definitely a setup well-playing with the available alcohol :-D.

Afterwards, another speaker informed us that the wi-fi access keys we received at the registration allows us to use a 6 APs/3 repeaters beast driven by an OpenBSD box – they want the audience to hack it because, well, “you are the Worst Case Scenario.” :-)

Then, the funny Hacker Hacker video was presented:


After a lousy and not so exciting first night (due to tiredness), we’ll wait and see what the next day would bring.

Sniffjoke – a sniffer-evasion toolkit

High capacity sniffers used in big cos and on border national gateways that collect user generated traffic on order to find possibly “criminal” patterns are today generally available for bandwidth to the 10Gbps, there will be soon appliances that’ll process streams of 100Gbps. Sniffjoke, by vecna and evilaliv3 is a tool that can inject into TCP connections outsider packets that will fool the intercepting sniffer but with no remarkable effect on the receiver. these packets for instance trick the sniffer into thinking that the connection has been reset even it is not true – by injecting a wrong-checksummed RST or a packet with a TTL less than 1 of the hop count – or try to consume its processing power by using known vendor-specific interpretations of the TCP RFC. Details: website, slides, wireshark thread.

WLAN router horror stories

Did you ever woder what happens when the wireless network password is directly tied to the device MAC address, from which it can be inferred because it is part of the essid? horror stories, as the an Austrian (ViBi) and a German (5M7X) researchers showed us. many carriers who sell wifi equipment ship it with similar vulnerabilities, as also mayhem and cyrax show us in this video (italian only)

We’re talking about a technology whose potential is not maximized, as a result leads to flawed the security measures, because of bad engineering and misleading instructions: some wifi apparatus manuals even recommended the user to never fiddle with the configuration and leave the default passwords in place. clever. Other examples of bad engineering include making the network key the last 4 bytes of the internal eth MAC address and then broadcasting that MAC via a multicast packet sent to (Samsung G3200 / G2210 / G3220).

Other companies, such as the synchron who produce the easybox has a patented way to provide a key recognition method, and direct correspondence between the mac and the key seed. eventually, there are even companies who sell their devices with the management SSHD open on the external interface, and who base the network key entirely on the internal MAC. Couple it with default passwords and you get the picture.

If you want to know more, you should get some armory and either reverse engineer the algorithms yourself, or participate to security conferences and ask the researchers for the slides :-). Once the industry will be ready, all the details will be revealed.

Hacking TETRA

Held by Harald Welte (@laf0rge), member of the gnumonks.de crew, the talk described a terrestrial radio communication technology that is similar to GSM but runs on lower frequencies of the spectrum, thus achieving wider coverage with less transceivers. TETRA employs ways to authenticate and encrypt communications, features a signaling channel over 140-chars messages are exchanged and identifies each user on the network using the match between the subscriber number and the terminal one.

TETRA is widely deployed over the world as a communication medium for public transport, public safety, firefighters, etc. it is a technology suitable for these uses, but laforge correctly reminded us that even if the tools allow us to implement secure networks, often the implementations of such tools is ineffective and prone to breakage.

He showed us how the signaling on the network works. He started by first showing us packet dumps in wireshark, thanks to chinese hackers who wrote the dissectors. He was also able to associate to a tetra network used by BVG, the german public transportation system, and listen to a call between the headquarters and all train drivers: the former was asking the latters to push a button contemporarily. Yes, sir: in the 21st century you still need people to do that. Awesome. If you want to build your own, you should first learn how radio communication works, buy yourself a FUNcube dongle and check out the OsmocomTETRA project. An introduction is available on heise.de.

Printer Hacking

Find vulnerability into a printer management interface, write a java applet that exploits it, define hooks to drive it from Javascript, and your web-based printer vulnerability scanner is done!

I missed the first part of the talk, so I don’t have the details, but as the speaker told me later when I asked him how it all fitted together, “it’s everything on the paper!” so just RTFM here :)

Chip & PIN is definitely broken

Moving on in the list of badly-implemented technologies, nowadays credit / debit cards are vulnerable to a typical downgrade attack when it comes to validating the PIN. There are different types of chips, ones that only allow plaintext authentication between the POS and the chip, others that employ a challenge-response mechanism, and almost every one of them allow the PIN to be validated online with the bank.

No matter what, the SIM exposes an interface to the card readers, that can be queried and whose communication can be eavesdropped by an intercepting device. Because cards must be backwards-compatible with existing POSes and viceversa, such an intercepting device is able to alter the advertised capabilities of the card and force the POS to use plaintext authentication, and then intercepting the pin as the user types it.

Such a skimmer is a 4×4cm device, that can be installed inside a POS or an ATM, thus possibly going unnoticed for a long period of time. And even if there are insurances that cover you against these frauds, if you’re a frequent traveller, you can hard time in demonstrating you were a victim, both because the card number and pin match, and because this is now considered as a “secure” technology that cannot be broken.

Thanks to Andrea Barisani and Davide Bianco for making us aware of the downgrade flaw. If you want to know more, here are their slide published on their company site, inversepath.com.

FreeBSD kernel exploitation

As years go by, stack smashing is still alive and powerful, as argp explained during his talk. CVE-2008-3531 is a known vulnerability of the FreeBSD kernel that allows code execution in kernel space, whilst the UMA – FreeBSD’s memory allocator – has known flaws in it as well.

Without going into deeper details, the main issue here is the “if it ain’t broken, don’t fix it” approach employed by many system administrators when it comes to production machines: as a result, they do not get updated for years. Maybe it’s not broken today (if ever, ya’now 0dayz?) but it will be broken tomorrow, and you’ll get pwned if you do not keep up to date. WORD.

Advances in win32 ASLR evasion

When I think about Microsoft products, I always feel that they’re not built to be used by people, because it looks to me that coders who write them never care about using them in the first place. They do not eat their own dog food. just go on and try to use IE developer tools and you’ll get the point.

Their software is written for business, it must match some higher-order requirement agreed by some random manager 7 layers up in the hierarchy, and very often it fails to implement them correctly. Thus, as JF pointed out during the talk “Microsoft has spent a lot of money fixing the exploitation problem, but they only created more of them”. Word, dword and qword! :-)

ASLR is a mitigating factor for exploits that assume the return address of vulnerable code lies in at a well-known address in memory. These locations are used to compute where to write the shellcode in order to trigger its execution after exploitation. If the return address gets randomized (thus Address Space Layout Randomization), then the exploit will just crash the vulnerable software by making it reference an address outside its space.

Problem is that, for some obscure side effect, for each 16 threads you create, if their base address is even (0x02xxxxxx, 0x04xxxxxx), 13 of them will end up being based at a known location, thus making ASLR ineffective and bypassed. PWN!

Check JF slides out here – thanks for sharing @not_me!

JF apologized at least 4 times before ending up closing its laptop and ending the presentation with vodka and gin, because he said that he did not do a good work in explaining but, as I also told him later, he was more than effective: it’s not easy at all to understand how all the side effects played together. Only he that was on this stuff for months was able to see the patterns in addresses and convey a successful exploitation of an ASLR-protected process. Enlightening!

Modern heap exploitation using the low-fragmentation heap

I’m no MM guy and I didn’t get most of the concepts of the talk, but its abstract is very explanatory:

Heap memory management has matured over time, but with complex new code comes new opportunity for exploitation. This presentation will focus on understanding the Low Fragmentation heap on Windows 7 (32-bit). After a foundation of integral concepts is laid, new exploitation techniques will be thoroughly discussed. Finally, we will use this new found knowledge to leverage supposed non-exploitable vulnerabilities. Specifically we will cover a case study showing how to craft an exploit for the IIS FTP 7.5 denial of service (http://blogs.technet.com/b/srd/archive/2010/12/22/assessing-an-iis-ftp-7-5-= unauthenticated-denial-of-service-vulnerability.aspx-= unauthenticated-denial-of-service-vulnerability.aspx), resulting in full control of EIP.

What is interesting is that in order to use a memory allocation optimization subsystem to do what you want, you have to mix and match 7 different attack primitives, understand thoroughly how the block allocations are made and how they interact with the host CPU. As well as battle with all the side effects in order to write in the program counter the address you want to execute. “@You say JMP, we say what addr@”, a T-shirt was correctly stating in front of me. :-)

Incredibly complicated as it sounds, Chris Valasek was able to find, exploit and explain the vulnerabilities, with a mental exercise that is both brilliant than inspirating: always dig deeper, and you’ll be able to reach any goal.

Here are Chris’ slides, but you’ll have to enable Flash unfortunately.

Exploiting the Hard-Working DWARF: Trojans with no Native Executable Code

Could you ever imagine that in every GCC-compiled binary may lie a complete virtual machine subsystem, that gets invoked on every call/ret and has the ability to read and write the heap and every cpu register? indeed it is, and it’s called DWARF, a debugging instrumentation used by GDB to help the developer debug his/her software.

“It’s a DWARF and ELF story…” LOL! :-D.

What’s interesting is also that DWARF code is not considered by analysis tools as being part of the object code of a binary, thus making it an injection vector to attach trojans to a binary. Moreover, DWARF is platform and architecture independent, being a finite-state machine on its own: a DWARF-based trojan can be used over multiple platforms and attached to any ELF binary.

If DWARF code is present, it gets executed for each function called and on each return, as the stack gets unwinded, and yes you can read and write the CPU and on the heap. Neat. For all the details, check the whitepaper out.

Here we see an example of hobby-ism and poor project management on the GCC side – no offense intended of course – but such a crafted and complex subsystem ends up being available in the vast majority of OSs, possibly making up an infection vector.

I infer this because DWARF is an obscure, undocumented, cargo-culted piece of code written because somehow today and tomorrow the GDB devs needed instrumentations, and GCC devs built in an excessively powerful tool to support them, but said tool can then be abused and no one really know how the first releases work – unless you skim through random posts on the GCC mailing list. More recent releases are pretty documented, though.

Funnily enough, I think to support GDB, even the LLVM compiler infrastructure, built with clean design from the ground up, uses DWARF! That said, the moral of the story is that ugly hacks today, will call you for trouble tomorrow – or the next day.

Party! (Music Here)

- “hey man, are you the guy behind the openbsd box acting as an host AP for the ph wifi network?”
- “yeah, I am”
- “may I ask you a root shell?”
- “you want… WHAT?”
- “yeah, you know, I’d like to issue ifconfig, brconfig, pfctl -s, ls -lrt /etc | tail, stuff like that – just to see how the thing works :)”

Kudos to the OpenBSD panda, that didn’t give me a shell, but illustrated me how the dorepanda access point “cluster” works, creating a network that spans all the 802.11b/g and n spectrums. It load balances clients between the APs, using cryptography to verify the AP identity and trying to prevent eavesdropping.

- “man, you are actually a grey beard at a security conference!”
- ”... so what?!”

... and then you talk with a 20-yrs experienced DBA that tells you “Oracle is flawed by design” and you chat with him about how the security scenario has changed over the years.

- “nothing really changed, it just got more complicated along the way”
- “you mean, the bottom line is always you have to snatch some shellcode in memory and then find a mean to execute it?”
- “exactly – you may have an NX bit, ASLR and canaries, but there’s alway a way around it.”

A good sysadm friend of mine told me similarly, in terms of “as long as I read enough documentation, I’m able to set up and deploy whatever system. no challenges anymore.”

To me, confs like this one make you wonder, think and activate mental circuitry that stimulate your passion: you see brilliant humans solving tricky problems, walking deeply into details and actually learning new things in the process. human beings whose model of the world includes sequences of interactions happening inside the machine. Like a skilled netadmin recognizes AS numbers from netblocks, a kernel hacker learns to recognize portions of the address space: he/she literally breathes within the operating system.

It amazes me how I found strong matches of Jeff Hawkins’ theory of intelligence (TED video) in hackers’ minds. I talked about the HTMs paper to the folks I met, and I was surprised no one of them knew about a technology aimed at building intelligent machines by reimplementing the human brain’s cortical algorithm in silicon. For instance, Chris Valasek and JF talks demonstrate the basis of expertise: more and more you receive inputs from a context, the more your brain will be able to see deeper and complicated patterns, because they get moved lower in the cortex hierarchy, whose job is to recognize details – as they did with ASLR and the low-fragmentation heap.

- “sir, you are the only one wearing a tie in this hall”
- ”...”
- “so you must definitely work for Microsoft!”
- “ahem, no…”
- “ah, ok so my assumption was incorrect. sorry for bothering! :D”

At 5:15, it’s really better to get to bed, waiting for the next good morning!

Day 3 – 98% Zero-Day Virus Detection

After such a party, both the social engineering and Exploit Next Generation++ talks were a bit foggy, I ever failed to recognized the metasploit source code language (ahem). :-)

Then shirtie (@skjortan) on stage illustrated how you can use a Bayesian / MAXENT classifier to identify unknown, 0day malware.

Exactly like an anti-spam filter catches spam by first analyzing a training set, identifying the recurring patterns and then matching them with novel data, malware as well as spam has typical features that can be used to find it. For instance, the presence of a reference to the CreateProcess API or the absence of the <a href="http://en.wikipedia.org/wiki/Pentium_FDIV_bug">_check_fdiv</a> one, to whether the binary is UPX-packed or not.

The technology looks effective, it is not a replacement of a signature-based AV rather it is an augmentation, because it is prone to false positives, but it is the only that identifies unknown, 0-day malware – the one for which no signatures exist.

Offensive XSLT

XSLT is a language used to transform XML documents into another form, and it is a turing-complete language executed either in the server or in the client context. it is used both by content management systems and in client-side applications, the most prominent example being the index of a subversion repository.

Because XSLT is a (functional) programming language, it offers means to read and write files and to execute code. If the user input is not sanitized and/or the XSLT engine exposed, it can be used to pwn a machine. Of course, the abusable features can be turned off if they’re not needed, or alternatively wrapped with a secure API if they are. Check Nicolas Gregoire’s slides out here. Liferay users, you’ve been warned :-)

Final words

Thanks @nhaima for telling me about the conf and allowing me to have a grant (thanks nobody :)

Thanks @techdoer for editing the post – hopefully this is my first one without grammar errors :-D

Thanks @phenoelit and @41414141 for organizing the party (you’re da men), everyone who was there. I hope to see you soon on stage :). Yay!

Thanks to @jodosha efforts and praising the former Javaday event, now renamed into codemotion that brought in Rome many Ruby developers from Milan, Padua and other parts of Italy – the first official Ruby Social Club in Rome has been a great success. Of course, officialty is measured only in the amount of twitter spam posted about it! :-): earlier RSCs in Rome go back in time to 2006 organized by current mikamai members and more meetups promoted by @jeko in 2007 .

What matters is that there’s a community, there’s a passion, and there’s love to share knowledge - no matter who holds the meetings, the important thing is that they’re being held :-).

The event was simple and direct - some beers first, then my keynote on RVM and Ruby interpreters, then Luca’s one announcing his minege.ms project and after real social networking :-). I met @gravityblast after much time we didn’t meet, knew the PIP group and met @svarione , @punkmanit , @leonardoperna , @riggasconi , @ogeidix and other smart people. Moreover, we spent quite some nice time together, making up a really lousy and funny week-end. Of course, huge kudos to @nhaima ’s car - that tirelessly carried us around Rome for two days :-)

Now, looking forward to the next meetup, thanks everyone who participed, who offered me beers and, last but not least, thanks to @etapeta for bringing me in time at the meeting - you’re the real hero :-).

I spent the last two days trying to set up the Aluminium Mac Mini (rev. 4,1) as a home NAS server with encrypted storage, and I wanted a BSD system on it. There’s already an embedded OpenBSD onto the soekris gateway, and another companion would have been nice. :-)

Guess what, there’s no way out:

  • FreeBSD 8.1 doesn’t complete the boot process, due to a bug in the SATA chipset, NV MCP89;
  • FreeBSD 8.2-RC1 boots but, due to the same bug, doesn’t recognize any SATA drive nor any USB umass device;
  • NetBSD 5.1 boots fine, handles SATA disks via the generic pciide driver (no DMA, thus quite slow) but, unluckily, doesn’t handle the BCM57762 ethernet controller. I tried with quick and dirty patches to bring the bge driver up to date with -current, but still no luck: the MII link detection works, the card transmits but doesn’t receive. The sdmmc controller as well works with -current but not with 5.1-RELEASE. ACPI works correctly;
  • OpenBSD 4.8 boots, can access the SATA drives without DMA, and recognizes the bge network card, but exposes the very same behaviour as NetBSD 5.1 with the -current driver fitted in;
  • DragonFlyBSD 2.8.2 doesn’t even enter kernel mode, I suspect due to ACPI bugs;
  • PureDarwin didn’t inspire me too much, due to the many blocking issues.

All of them support encrypted storage, I built up a NetBSD CGD disk flawlessly onto dk wedges; FreeBSD has got the interesting gbde(8) and geli(8) GEOM-based tools that I wasn’t able to test, while OpenBSD supports crypto via a softraid personality. Unluckily, support for the, nowadays, exotic Apple hardware is a no-brainer.

So, with no other way left open, I decided to go the Linux route, using the excellent sysresccd, that I elect today as the successor of the pld-linux rescuecd, companion of endless system recoveries :-). Anyway, you’ll need the 2.6.36 kernel to make it boot onto the MacMini4,1, due to the aforementioned MCP89 bug. Ethernet card and SD card reader work out-of-the-box.

Now, I’m playing with LUKS and, while I’m not that competent in cryptography, looks like it is more evolved than the *BSD counterparts, and anyway it is more versatile tool than the tools in OpenBSD and NetBSD. On the latter, having to set up GPT and DK Wedges to make the CGD and synch MBR and Disklabel to make the boot loader work (yuck!), everything coupled with rEFIt is quite a mess™. There’s a GPT loader for NetBSD but I hadn’t a chance to try it out.

I hope this information is useful to anyone who tries a similar adventure, comments are appreciated :-).