newstalk week 20/2014

N-talk

Dušan Klinec

Faculty of InformaticsMasaryk university

13. 5. 2014

Dušan Klinec (FI MUNI) Klinec, N-Talk 13. 5. 2014 1 / 33

Outline

1 Local root exploit for linux kernel

2 ATM strikes back

3 Italian-job style hacks

4 NSA backdoors in exported servers and routers

5 IETF mull anti-NSA crypto-key swaps in future SSL

Critical linux kernel bug

Local root exploit for linux kernel

Local root bug in a linux kernel

Local root exploit / local DoS exploit→ critical vulnerability.Present in kernel, almost all linux versions affected (Android?).Bug from version 2.6.31-rc3, 2009.Present in current versions 3.14.3 including testing version 3.15.Critical impact for systems with local user accounts (e.g.,webhosting companies, university servers, ...)

CVE-2014-0196.The n_tty_write function in drivers/tty/n_tty.c in the Linux kernelthrough 3.14.3 does not properly manage tty driver access in the"LECHO & !OPOST" case, which allows local users to cause adenial of service (memory corruption and system crash) or gainprivileges by triggering a race condition involving read and writeoperations with long strings.

No atomic guaranteee in atomic_write_lock in termios settingsLECHO & !OPOST.Not allowed to call TTY buffer helpers like tty_insert_flip_stringconcurrently.This may lead to crashes when concurrent writers call pty_write.

Technical details

tty_insert_flip_string_fixed_flag

int space = __tty_buffer_request_room(port, goal, flags);struct tty_buffer *tb = port->buf.tail;...memcpy(char_buf_ptr(tb, tb->used), chars, space);...tb->used += space;

Race condition:

__tty_buffer_request_room

memcpy(buf(tb->used), ...)tb->used += space;

memcpy(buf(tb->used), ...)

B’s memcpy is past the tty_buffer due to the previous A’s tb->used increment.

Technical details

tty_insert_flip_string_fixed_flag

int space = __tty_buffer_request_room(port, goal, flags);struct tty_buffer *tb = port->buf.tail;...memcpy(char_buf_ptr(tb, tb->used), chars, space);...tb->used += space;

Race condition:

memcpy(buf(tb->used), ...)tb->used += space;

memcpy(buf(tb->used), ...)

B’s memcpy is past the tty_buffer due to the previous A’s tb->used increment.

Exploitability

Working local root exploit available athttp://bugfuzz.com/stuff/cve-2014-0196-md.c

220 lines, easy to read, simple.Privilege escalation, very easy for script kiddes / automated testing.Cons: Directly uses features from kernel version 3.14+

Wotking local DoS exploit available athttp://pastebin.com/raw.php?i=yTSFUBgZ

149 lines, easy to read, simple.Sucessfully tested on my local PC & lab server.Should work on all affected versions.

Universal local root exploit will appear will high probability soon...

Exploitability

Kernel bug fix

https://github.com/torvalds/linux/commit/4291086b1f081b869c6d79e5b7441633dc3ace00

Debian fixed yesterdayNot present in RHEL 5.RHEL 6 and Ubuntu still not patched.

Kernel bug fix

Debian fixed yesterdayNot present in RHEL 5.RHEL 6 and Ubuntu still not patched.

ATM strikes back

Research conducted at ETH Zurichhttps://www.ethz.ch/en/news-and-events/eth-news/news/2014/

04/der-bancomat-schlaegt-zurueck.html

Basic idea: protective material, aggresive reaction on damage.

ATM strikes back

Inspiration for the research

Inspiration taken from the nature: Bombardier beetle.Probably the most aggresive chemical defence system in nature.

ATM strikes back

Scheme of the beatle’s defense system

212 ◦F = 100 ◦CDušan Klinec (FI MUNI) Klinec, N-Talk 13. 5. 2014 13 / 33

ATM strikes back

Description

A chemical defence mechanism (self-defending surface).Designed to prevent vandalism.Composed of several sandwich-like layers of plastic.Chemicals: hydrogen peroxide H2O2, manganese dioxide MnO2.Layer of lacquer separates these chemicals, impact→ mixingchemicals→ wild chemical reaction.

ATM strikes back

Description

ATM strikes back

Description

ATM strikes back

Description

ATM strikes back

Description

ATM strikes back

Chemical reaction

Chemicals: hydrogen peroxide H2O2, manganese dioxide MnO2.

Reaction: H2O2MnO2−−−→ 2H20 + O2 + ENERGY

MnO2 is a catalyst, thus preserved after reaction.MnO2 lowers activation energy, room temperature enough tolaunch decomposition of the H2O2.Temperature reaches 80 ◦C.Like a fuse, very little mechanical energy→ release a muchgreater amount of chemical energy.

ATM strikes back

Chemical reaction

ATM strikes back

Chemical reaction

ATM strikes back

Chemical reaction

ATM strikes back

Chemical reaction

ATM strikes back

Chemical reaction

ATM strikes back

Chemical reaction

ATM strikes back

Attacks on ATMs on the rise→ film surface protection.Q1,Q2 in 2013, more than 1,000 attacks on ATMs in Europe.Losses of EUR 10 million.

ATM strikes back

Rendering banknotes useless

Goal: protect cash in ATMs.Banknotes marking system already exists (reaction to intrusion).Depends on an electricity.Complex system (sensor, motor, chemicals)→ expensive.Known cases of malfunction.New surface: added DNA enveloped in nano-particles.If the film is destroyed, both the foam and the dye are released.

ATM strikes back

Conclusion

Lab experiments shows this method is effective.Relatively cheap protection method, 40 USD per m2.If attacker knows about it, may somehow hack this system.Chemical reaction needs energy, freezing this material may help.

ATM strikes back

Conclusion

ATM strikes back

Conclusion

ATM strikes back

Conclusion

Italian-job style hacks

Hacking traffic lights

Security researcher Cesar Cerrudo @ IOActive Labs.http://blog.ioactive.com/2014/04/

hacking-us-and-uk-australia-france-etc.html

Basic idea: hacking traffic lights, intelligent traffic signs.Low technical details, will be revealed on Infiltrate 2014conference next week.

Several vulnerabilities discovered.Anyone can take complete control of the devices, send fake data.Can have catastrophic chaotic effects.According to Cerrudo, more than 50,000 traffic control devicesaffected.Affected devices deployed in US: New York, Washington DC, SanFrancisco, Los Angeles, Boston, Seattle, etc.Worldwide: United Kingdom (London, Blackburn; Belfast), China,Canada, Australia, France.

Exploitation quite easy, software exploit, commodity availablehardware, up to 100 USD.Tested from a drone flying at over 200 meters, worked.Theoretically possible up to 1 or 2 miles away with a better droneand hardware equipment.Flying a drone is not illegal in the US (due to court precedent).Possible to create a worm, that can infect vulnerable devices inorder to launch attacks affecting traffic control systems later.

If device is compromised, almost impossible to detect it (veryexpensive).Numerous devices could be already compromised.Very difficult to upgrade firmware.

Exploitability

Make traffic light to stay green more or less time.Stay red and not to change to green.Flashing traffic lights (a.k.a. idle mode).Cause electronic signs to display incorrect speed limits.Could cause serious (even deadly) issues.

Exploitability

Proof-of-the-concept

"passive" on-site tests ("no hacking and nothing illegal").

Proof-of-the-concept

Reaction

Vendor contacted in September 2013 through ICS-CERT.Researcher was told by ICS-CERT that the vendor said that theydidn’t think the issues were critical nor even important.Regarding one vulnerability:“Since the devices were designed that way (insecure) on purpose,they were working as designed, and that customers (state/citygovernments) wanted the devices to work that way (insecure), sothere wasn’t any security issue.”

Reaction

Mini-news

NSA backdoors in exported servers and routers

USA accused China for backdooring exported hardware.Snowden-leaked documents suggest NSA is doing the exactlysame thing.”The NSA routinely receives – or intercepts – routers, servers andother computer network devices being exported from the USbefore they are delivered to the international customers.“The agency then implants backdoor surveillance tools,repackages the devices with a factory seal and sends them on.Eventually, the implanted device connects back to the NSA.Chineese HW represents not only an economic competition butalso surveillance one.Source: No Place to Hide, by Glenn Greenwald is published on 13May 2014 by Hamish Hamilton.

IETF mull anti-NSA crypto-key swaps in future SSL

TLS v1.3

Planning to drop RSA key exchange removed from the standard.Ephemeral keys are preferred (Diffie-Hellman key exchange,Elliptic Curve Diffie-Hellman key exchange).RSA cons: if long term secret compromised, ability do decryptpast sessions.Desired property of key e.m.: Perfect Forward Secrecy.”The removal of RSA in the next version of TLS is a perfectexample of how Snowden has improved our privacy“, MatthewGreen, a professor of CS @ Maryland’s Johns Hopkins University.

Questions?

References

https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-0196

https://www.ethz.ch/en/news-and-events/eth-news/news/2014/04/

der-bancomat-schlaegt-zurueck.html

http://lizwason.wordpress.com/2013/01/22/hugabug-1-bombardier-beetle/

http://biol2205mattsbombardierbeetles.weebly.com/physiology.html

http://www.freepatentsonline.com/6605685.html

http://www.gizmag.com/bioinspired-foam-defense-system/32017/

http://blog.ioactive.com/2014/04/hacking-us-and-uk-australia-france-etc.html

http://www.theguardian.com/books/2014/may/12/

glenn-greenwald-nsa-tampers-us-internet-routers-snowden

http://www.theregister.co.uk/2014/05/08/rsa_depreciated_from_tls

newstalk week 20/2014

Internet

linux kernel local root

local users

linux versions

linux kernel cve

local user accounts

critical impact

critical vulnerability

current versions