Users obtain a domain name to establish a unique identity on the Internet. Domain names are not only used to serve names and addresses of computers and services but also to store security controls, such as SPF or CAA records. Many of the Internet protocols were designed at a time where built-in security was not a requirement. The IETF continues to standardize protocol extensions to address today’s security needs.
For some protocols security is added with controls stored in your domain names zone file. In order to have the desired effect, the pre-condition is of course that your domain name is secure. In other words, the security of your application that makes use of controls in DNS is only as secure as the security of your domain name.
Hijacking a domain name because of weak credentials at the registrar may get the job done but this is far from stealthy and will likely not last long. In many cases it is sufficient to hijack an abandoned subdomain. Taking over abandoned subdomains may be unnoticed by the owner for a very long period of time making it also very useful for targeted attacks.
Picture 1: update.ft.com has been hijacked and the content from the ft.com front page is mirrored with a fake article about subdomain hijacking. Note: the website is not online anymore, Financial Times has been notified to remove the abandoned record from their zone file. A Certificate Transparency (CT) log proves that a TLS certificate has been issued for this demo site.
On a daily basis we collect tons of Spam emails, which we analyze for malicious content. Of course, this is not done manually by our thousands of minions, but automated using some Python-fu. Python is a programming language that comes with many libraries, making it easy for us to quickly perform such tasks.
Python’s email library deals with, well, emails. And it does it well. But on October 3rd, we encountered an attachment that wasn’t there – at least according to Python’s email library.
Left: Outlook Web does not show the attachment Right: Thunderbird does show the attachment
Now how could that happen?
Emails do have a certain structure, which is described nicely in RFC #822, RFC #2822, RFC #5322, RFC #2045, RFC #2046, RFC #2047, RFC #2049, RFC #2231, RFC #4288 and RFC #4289. Even though these RFC’s are clear in their own way, an illustration might help (we focus on multipart emails only) to understand why Python’s email library got fooled.
Recently I was quoted saying “… .ch and .li are the most secure (top-level) domains!”. In the same meeting, Security Rock Star Mikko Hyppönen claimed, “Surfing the Web with your laptop is the most dangerous thing you can do in the Internet.” So what is true, what is false? Rather than speculate about obscure statistics I’d like to illustrate one of the big problems we face in .ch today, namely using ads as a back door to reach victims through reputable sites.
Ads: enter through the hallway
Malware distributors have one goal: spreading their stuff as widely as possible. This is achieved through different means. Malware was traditionally distributed – and still is – through e-mail attachments. This was the case, for example, with the Retefe malware. Alternatively, web pages can be hacked and used to spread malware by exploiting browser bugs. SWITCH has been very active, through its Safer Internet initiative, in working to reduce this infection vector. In fact, we’ve been so successful, that drive-by is very scarce in Switzerland, hence the statement that ” … .ch is one of the most secure ccTLDs”. Drive-by websites are always hacked, but in most cases they are not very popular websites, since popular websites are typically well protected. Many of the later ones offer a backdoor tough: ads! News sites in particular make most of their revenue by selling on line ads, which explains the “ad-war” arms race between ad-blockers an news agencies (see our Security Report on anti-anti-ad features). A very common way is malvertising, a term coined by William Salusky. Salusky found ads that were in fact carrying malicious payloads. Let’s look at a slightly different scenario, namely a legitimate but compromised ad server. While technically a different scenario it has the same effect on the end user.
Most people would think that visiting a website just serves you content from that site but this is not true for most of the large sites, in particular news sites. They import contents such as videos, trackers, counters, scripts and especially ads from third-party sites. These are not controlled by the original site, and often import content themselves from yet another site. Thus, a well maintained site with high security standards will often import stuff from sites with lower security. Think of it as sitting in a highly rated restaurant that has one bad food supplier.
The image below shows all the external sites involved whenever you visit three popular news sites.
The above example shows what happens when you visit three popular Swiss newspapers. Triangles denote third-party sites from which content is imported when you visit the respective news site. The visualisation was done using the Mozilla addon LightBeam
In recent weeks the Angler exploit kit has become the dominating tool for DriveBy attacks. Cleaning Angler compromised web servers is a challenge which has been well mastered in Switzerland, thanks to the close collaboration of Swiss hosters and SWITCH.
The culprit
On Sunday July 5 an the Italian ‘offensive security’ firm HACKING TEAM got hacked and all its files were made public. This included a couple of zero day exploits. Only two days later one of these was already used in the wild by the notorious Angler exploit kit. This is not surprising: Angler today is the most sophisticated exploit kit. Since its inception in 2013 it sported several new innovations which are today uses by others. According to a Sophos blog Angler’s “market share” rose from about 22% last fall to more than 80% this spring.
The payload
Angler used to distribute a variety of different malwares, from ransom-ware to banking trojans. However it seems with the rapid growth of the kit it also focused on distributing mostly Cryptowall 3.0. This malware encrypts all the files on an infected system and demands a hefty ransom of several hundreds of Euros to unlock them. Many people claim to not have “anything important” on their PCs to then discover that all their family pictures of the past ten years are gone. An it’s not looking better for businesses that lose all their data, including their backups on USB disks.
Cleaning Infections in Switzerland
SWITCH has been cleaning up misused domains since several years now through its Safer Internet campaign. We have processed thousands of domains and thus protected visitors of Swiss websites from the evil of exploit kits, such as Angler. Infection rates of Swiss websites have indeed gone down over the past month, or so we believed. On the 22. July 2015 however, the good folks from the National Cyber Security Centre Finland (NCSC-FI) and abuse.ch have managed to make a small dent into Angles infrastructure. A total of over 200’000 compromised URLs worldwide were reported that are misused by Angular.
Distribution of web servers, which are misused by the Angler exploit-kit.
Of these 166 where in the .ch and .li top level domain and thus could be entered into our program. We reported these URLs to the respective domain owners as well as the hoster we have contacts to. Checking on the 23. July over 90% of these domains have been cleaned up and a handful have been added. As of the 24. July 2015 only a few sites remain infected.
This means that Swiss hosters are doing an excellent job. Cleaning a web page is not simple. It’s not enough to just remove the the offending code from that page itself. It’s known that the Angler crew installs several back doors, all of which have to be found and removed. These back doors often are webshells, which give full control over the entire web space of the server. The respective php files are obfuscated and not easily recognizable.
The Webshell used by the Angler crew. The white box shows the obfuscated php code. The shell gives full access to all resources the webserver has access to.
Some of the hoster report information back to us for which we are very grateful. This information can then be used to make the analysis better and discover new attack patterns quickly.
Conclusion
The close collaboration and exchange of information between all the stakeholders allows for a very rapid reaction to threats. Cleaning these web pages needs substantial resources by the hosters and also SWITCH. But it’s well invested: Taking down these pages quickly protects visitors from being infected by Cryptowall and saves their valuable data, be this treasured personal files or critical business information.
Anna is the director of a small kindergarten in Zurich. To give the kindergarten a home on the Internet, she registered a domain name and put up a website where parents can get up-to-date information about the kindergarten. A friend helped her to install a popular open-source content management system (CMS) for the website, so that she can change the menu every week and perform other updates herself. The parents of the kids were delighted to have access to this information online.
Three months after the website went online, one of the parents called her, telling her that the website was no longer available, and a warning was displayed instead. He also told her that he had a virus on his home PC and had to reinstall his operating system and change all his Internet passwords. When she talked to other parents that day, they told her the same.
Stuxnet: Even though Stuxnet was discovered more than four years ago, Kaspersky revisited the subject and published new technical information about some previously unknown aspects of the Stuxnet attack.
PWC published their Global State of Information Security Survey 2015. According to the survey total financial losses attributed to security compromises increased 34% over 2013. Here you can download a paper with the key findings.
What comes after CVE-2014-9999? The international database for Common Vulnerabilities and Exposures faces its ‘Y2K’ moment. Read more about the syntax change here.
Black Hat USA 2014: The talks from this years Black Hat Security Conference in Las Vegas are now available online…
DEF CON 22: …and some first videos from DEF CON 22 are uploaded as well.
If you don’t have time to watch all these talks and are only interested in the “10 most terrifying security nightmares [OMG!] revealed at Black Hat and DEF CON”, this article is for you.
BadUSB is a term for a new form of malware that operates from controller chips inside USB devices. Learn how an USB thumb drive changes DNS settings in Windows and more in this interesting presentation (PDF) from SRLabs.
McAfee Labs reports that a new ransomware called CryptoWall uses Tor for communication and demands Bitcoin from the user in exchange for the private key to decrypt the files. “The use of Tor and Bitcoin in this operation make tracing the attackers more difficult” writes McAfee.
Isreal’s Homeland Security writes that anonymous hackers have launched DDoS attacks against network infrastructure from Israel. The attacks also affected DNS name resolution on domain names ending in .co.il.
The Register writes that Security outlet VUPEN has revealed it held onto a critical Internet Explorer vulnerability for three years before disclosing it at the March Pwn2Own hacker competition. VUPEN makes money by selling exploits to its customers.
The Moscow Times writes that Russia’s Interior Ministry has put out a tender on its official government procurement website for anyone who can identify Tor users. On a related note, the Tor team issued a security advisory this week, warning operators of hidden services about attacks to deanonymizing users. And if that’s not enough Tor news for this week, according to the Tor project’s latest annual financial statements (PDF), the US government increased its funding to 1.8 million US dollars in 2013!
Mobile Security: FireEye researchers have discovered a new software which takes Android malware to a new level by combining multiple malicious activities into one app.
After all, new research shows that ‘123456’ is a great password: Websites that would not present a threat if hacked should get throwaway credentials.
World Cup & Threat Intelligence: According to the Imperva Data Security Blog, Hackers like soccer so much, that they put their weapons down during the World Cup Finals. But during the rest of the matches, attacks actually increased.
sagt sinngemäss Jeremiah Grossman [1], ein alter Hase im Bereich der Web Application Security. Zwar vertreibt seine Firma auch einen eigenen Webbrowser mit Fokus auf Security und vor allem Privacy, Recht hat er trotzdem: Täglich verwenden wir Technologien, welche das Etikett “Broken by Design” tragen (sollten). In diesem Artikel befassen wir uns mit zwei Themen: Cross Site Request (Forgery) CSR(F) und Certificate Authorities (CA). Die Probleme sind seit Jahren bekannt. Heute wurde gerade wieder ein CSRF-Exploit für WordPress 3.9.1 publiziert. Und ja, das ist die aktuelle WordPress-Version.
CSR(F) – Cross Site Request (Forgery)
Cross Site Request Forgery ist im Gegensatz zu seinem Bruder Cross Site Scripting nur marginal bekannt. Dennoch belegte CSRF 2010 in den OWASP Top Ten Platz 5, und im Jahr 2013 immerhin noch Platz 8. Es handelt sich folglich um eine häufige und durchaus kritische Sicherheitslücke in Webapplikationen. Doch was ist CSRF und was hat das mit “Broken by Design” zu tun?
Viele Webseiten binden externe Ressourcen, beispielsweise Bilder, Javascripts oder Werbung, ein. Das Adjektiv extern verweist hierbei auf eine andere Domäne. Ein Beispiel: Was geschieht, wenn man auf die Webseite einer typischen Schweizer Tageszeitung http://www.typischeschweizertageszeitung.ch/ geht?
Es werden Ressourcen von typischeschweizertageszeitung.ch geladen.
Es werden weitere Ressourcen von beispielsweise adtech.de, cxense.com, cxpublic.com, visualrevenue.com, wemfbox.ch etc. geladen.
Es werden von cxpublic.com wiederum weitere Ressourcen von 2mdn.net, serving-sys.com etc. geladen.
Diese Anfragen für externe Ressourcen nennt man Cross Site Requests. Und jetzt? Zunächst muss man sich fragen, wer denn diese Requests im Auftrag von typischeschweizertageszeitung.ch ausführt: der Browser. Anschliessend muss man verstehen, dass dieser Request unter Verwendung sämtlicher lokal gespeicherter Daten (insbesondere Cookies) für diese externe Domäne abgesetzt wird. Schauen wir uns ein relativ harmloses Beispiel an:
<html>
<head>
<script type="text/javascript">
function csrf() {
alert("Auf 192.168.1.1 läuft ein Apache Server unter OpenBSD.");
}
function nocsrf() {
alert("Test fehlgeschlagen, aber vielleicht funktioniert etwas anderes? ...");
}
</script>
</head>
<body>
<img src="http://192.168.1.1/openbsd_pb.gif" onload="csrf()" onerror="nocsrf()">
</body>
</html>
SWITCH Security-Blog 