How Heartbleed Bug Affects Web Security

The news has been reeling with the announcement of the Heartbleed Bug. Want to know how the vulnerability works? Curious about how adversely this affects you or your organization? Our director of product security Michael Coates explains below.


HTTPS is layered on top of Secure Sockets Layer (SSL) or Transport Layer Security (TLS) to enable a user to securely communicate with a website without tampering or monitoring from intermediate parties.

However, on April 7, 2014 a serious vulnerability (CVE-2014-0160 – https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-0160) was uncovered within the TLS heartbeat extension in versions of OpenSSL that places the encrypted communication at risk. Attackers can leverage this bug to obtain the private keys from the webserver and use this information to decrypt and monitor communications that are taking place over SSL/TLS, exposing any sensitive data communicated by the user.

Scope of the vulnerability

1.0.1 and 1.0.2-beta releases of OpenSSL are affected including 1.0.1f and 1.0.2-beta1.

Apache, which uses OpenSSL for HTTPS, is used by 66% of all websites according to netcraft.com (http://news.netcraft.com/archives/2014/04/02/april-2014-web-server-survey.html). A study of the TLS heartbeat extension by Netcraft also identified that 17.5% of SSL sites may be vulnerable to the Heartbleed bug (http://news.netcraft.com/archives/2014/04/08/half-a-million-widely-trusted-websites-vulnerable-to-heartbleed-bug.html).

Is a patch available?

Yes – OpenSSL 1.0.1g was released on April 7, 2014 (https://www.openssl.org/source/). Impact of the vulnerability This vulnerability allows an attacker to extract memory contents from the webserver through the vulnerability in the heartbeat. As a result an attacker may be able to access sensitive information such as the private keys used for SSL/TLS.

  • Active Attack – Equipped with the private key, an attacker can silently monitor and decrypt communications between the user and the web server. As a result, an attacker could view private data such as passwords, credit card data, medical records and any other sensitive data the user exchanges with the website. In addition, the attacker could impersonate the target website to deliver fake, inaccurate or malicious data to the user.
  • Offline Attack – Some well funded attackers gather large amounts of encrypted data and store this data in the event they can later decrypt the information. Using the Heartbleed vulnerability the attackers could decrypt this information if it was obtained when passed between a user and a vulnerable website. This means that sensitive data exchanged up to two years ago could also now be at risk for exposure to attackers. Note: sites implementing Perfect Forward Secrecy are protected against this particular attack.

Who might exploit this vulnerability?

In order to decrypt data exchanged between a user and a website, the attacker must have access to network devices along the communication path. This attack could most easily be launched by state actors or criminal enterprises operating in collusion with network operators. In addition, individual attackers could leverage this vulnerability to attack individuals using a shared wifi hotspot.

Can attacks be detected?

Unfortunately, no. An attacker exploiting this vulnerability will leave no trace within the webserver logs. As a result it is not possible to determine if vulnerable web sites have been exploited.

What should website owners do?

  1. Verify if you are using a vulnerable version of OpenSSL.
  2. Upgrade OpenSSL as soon as possible.
  3. Reissue your security certificates for SSL/TLS. The vulnerability has been present for two years and there is no way to verify if your private key has been compromised as a result of this vulnerability. In addition, a compromised key would be used to silently monitor communications from your users and the attack would be undetectable. It is prudent to assume a breach and proactively reissue security certificates.
  4. Implement Perfect Forward Secrecy. This additional layer of security protects encrypted data from several potential attacks by using a per session random keys.

What should users do?

Unfortunately there’s not much a user can do. If you have an account at one of the many large websites that may have been affected, you can proactively change your password just to be safe.

Which large websites were impacted?

A partial lists of large websites that are impacted can be found here. This list includes websites such as yahoo.com, stackexchange.com, eventbrite.com, okcupid.com, suning.com, and squidoo.com.

What other concerns are there with this vulnerability?

The Heartbleed vulnerability allows an attacker to extract information within the webserver’s memory. As a result, a wide variety of information could be at risk including sensitive user or system data. In addition to placing webservers at risk, OpenSSL is also used by a variety of network appliances. These devices could be subjected to attack to extract sensitive information within memory.

Additional information

http://heartbleed.com
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-0160

Clarification: Michael Coates wrote this article.

Introducing the Shape Shifter

The security industry has focused largely on preventing malware infections, yet has failed to protect websites against attacks from hundreds of millions of infected consumer computers.

Today we launch the most advanced website defense. 




We founded Shape Security two years ago to tackle one of the hardest problems in web security: how to protect the front door of modern websites. The pervasive rise of malware-infected desktops, botnets and automated attacks threaten the foundation of the new Internet economy. We realized this called for a new approach to security—one that dealt with the reality that we can never truly eliminate malware from the desktop. 



The security industry has focused largely on preventing malware infections, yet has failed to protect websites against attacks from hundreds of millions of infected consumer computers. Our core strategy is to provide technology to protect websites even when they are serving infected desktops. In military terms, this is called “continuing to operate in a denied and degraded environment.” The ubiquity of malware-compromised desktops creates a degraded environment within which we must still find ways to enable everyday online activities like banking, shopping, socializing, and checking health records. 

To accomplish these goals, today we unveil the ShapeShifter, a web security product that protects websites from malware, botnets and scripts. 

Botnets: A Massive Criminal Infrastructure of Infected Computers


Today’s cybercriminals assemble massive networks of infected computers (botnets) to attack websites. Most security products fail to block such attacks because criminals are able to make their botnet-based attacks look like legitimate usage. 

These botnets are the backbone for a wide variety of high-volume, automated attacks against websites. Some of these attacks are well-known, such as when banking botnets steal millions of dollars across many online banking sessions, or when bots abuse basic website functionality, crippling websites with traffic that is almost impossible to block. Other attacks are much more subtle but just as damaging. For example, a botnet can slowly test stolen usernames and passwords against an e-commerce site in order to take over millions of accounts and defraud end-users. In fact, the same underlying mechanism is likely how miscreants will turn the the vast trove of over 100 million credit cards stolen from Target into money: they will use automated scripts running on botnets to purchase things like gift cards and other easy-to-sell goods from e-commerce websites. 

There are many examples of attacks that use botnets and automated scripts to exploit websites, but they all target the same inherent vulnerability: the fact that most websites are created from publicly viewable common building blocks (HTML, Javascript, and CSS). This allows criminals to treat websites as implicit APIs, meaning the website can be operated by bots and scripts that can perform any action the website supports. Older security technologies do very little to deal with this problem. Traditional threat signatures and reputation scoring don’t work very well, because most attacks look and feel like normal usage from computers belonging to legitimate human users. Rate limits are easy to avoid by distributing an attack across thousands of IP addresses in a botnet. The ineffectiveness of these and other traditional techniques led us to seek a solution that could disable attacks from malware, botnets and scripts. So we built the ShapeShifter. 



Introducing the ShapeShifter


The ShapeShifter uses real-time polymorphism as a defense—it dynamically changes website code to break automated attacks. Cybercriminals have long used polymorphism to hide malware by making the malware appear to be different upon every new infection. We harness polymorphism to make the source code of websites appear differently on every page view, which has the effect of defeating malware, botnets and scripts. All of this happens without creating any user-visible changes. The website looks and feels exactly the same to legitimate users, but the underlying site code (HTML, JavaScript, and CSS) is different on every pageview. Because bots must reference the content is some manner, this never-ending modulation of the site code breaks scripts and deflects attacks. Ultimately, the ShapeShifter aims to stop non-human visitors from executing large-scale automated attacks. This may help break the economics of breaches like the one Target experienced in late 2013, by eliminating the monetization path. 



Many web attacks are only profitable if automated. Criminal enterprises pursue profit: without automated scripts, many of today’s attacks cease to be economically viable. Instead of constantly detecting and reacting to threats, the ShapeShifter targets the economics of web hacking, and makes the preferred approach of criminals—automation, too expensive. This provides broad protection from automated attacks against websites and represents a completely new approach to security.