Are You At Risk Of Material Impact Because Of Bad SSL Certificates from WoSign and StartCom?

November 1, 2016, Arian Evans


Mozilla, the world’s second most popular browser, announced an important security decision last week to distrust a range of bad SSL certificates issued by Certificate Authorities (CAs) WoSign and Startcom, citing “technical and management failures”.

In a nutshell, the security industry agreed several years ago that SHA-1 is becoming risky to use for SSL certificates, and set a deadline of January 1st, 2016 for the industry to stop issuing SSL certs that use it. WoSign, which has acquired full ownership of Startcom, continued to issue SHA-1 SSL certs to customers, made to look valid by back-dating them, i.e., faking the date of issuance. There are several potential impacts from issuing weak certificates discussed in our technical blog, but the main business impact will be alarming “Secure Connection Failed” browser warnings when people visit your website. These certificates also present the risk for Man in the Middle attacks on users’ sessions and more.

Why would two Chinese CAs backdate certificates with weak ciphers, and then repeatedly deny it? Is this a shady operation, or simply a mistake? Keep in mind that it took Apple and Mozilla essentially saying they would put WoSign and Startcom out of business for them to finally respond to the claims of wrongdoing (we’ll let you draw your own conclusions).

Once WoSign was forced to come clean, the answer provided isn’t much of answer. To read it, jump to “9. Issue S: Backdated SHA-1 Certs (January 2016)” inside the official PDF response (if you are comfortable opening a Chinese PDF). The number of mistakes and poor judgment calls made at WoSign disclosed in this advisory, make it look like Hanlon’s Razor has been in effect there for some time.

If your organization is using SSL certificates from either of these CAs, you could be a victim of this. In fact, RiskIQ’s current global index shows 762,649 websites using Certificates belonging to the 2 CAs. If you are a RiskIQ Enterprise Digital Footprint customer, log in and go to your Insights Dashboard to review usage of WoSign and Startcom SSL Certificates.

If your organization has any websites, there’s a good chance that you're using bad SSL certificates from Certificate Authorities WoSign and Startcom.

Fig-1 For specifics on analyzing certificates, visit our technical blog

If you are unsure if—or where—you are running WoSign or Startcom SSL Certificates, you are certainly not alone. As businesses expand into digital channels, the challenge of finding and managing an increasingly decentralized attack surface grows exponentially. To demonstrate this risk, RiskIQ performed a quantitative assessment of threats facing the top 35 banks and financial service firms as a result of decentralized web and mobile attack surface in April 2015. The data we collected confirms this challenge:

  • 61% of 260,000 surveyed web assets were stored on external servers outside of IT department control
  • Only 39% of web assets were hosted on the bank’s primary ASN where they are more easily discovered and monitored
  • 97% of bank websites had a minimum of 13 broken SSL cert locations
  • 54% of bank websites had more than 100 broken SSL cert locations
  • 93% of banks had assets hosted with cloud-based IaaS providers, such as Amazon Web Services or Rackspace
  • Websites hosted outside of the primary ASN had roughly double the number of security errors per website as those on the official corporate network
If your organization has any websites, there’s a good chance that you're using bad SSL certificates from Certificate Authorities WoSign and Startcom.

Fig-2 RiskIQ’s Enterprise Digital Footprint inventories all the SSL certs in your environment

Most organizations have challenges managing their ever-expanding digital footprint and resultant Internet-exposed attack surface and struggle to find risk issues like invalid and potentially exploitable SSL Certificates. RiskIQ’s Enterprise Digital Footprint was purpose built to solve this problem.

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