Data Exfiltration: Not Much Has Improved Since the Yahoo Breach


December 4, 2023

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This December marks the seventh anniversary of the infamous Yahoo data breach. The company initially reported a breach of about 500 million accounts, then upped that number to over 1 billion accounts, and finally reported that as many as 3 billion user accounts had been compromised in the attack.

So, what has changed in the years since Yahoo got popped?

Takeaway: Account compromise on a mass scale is still a very prevalent problem, and if anything, the threat has become even more concerning as ransomware operators increasingly focus on data exfiltration as a key element of their attack progression.  

While victims in the Yahoo breach and countless others who have had their PII exposed still need to be concerned about identity theft and fraud, the potential impact from the Yahoo breaches pales in comparison breaches that may include data critical to our national security.  

The Yahoo breaches showed us we have a big problem with protecting sensitive data at scale, and the sheer number of accounts still being compromised by threat actors today is a reminder that we have not come close to solving for this threat.

Since the Yahoo breaches, the security industry has introduced some significant innovations. We have seen the advent of EPP/NGAV to catch novel malware strains, EDR to bolster threat hunting and DFIR, improvements in authentication measures and DLP offerings, the introduction of XDR for correlation across disparate telemetry sources for earlier detection and more, and that's great.  

The problem is attackers are innovating as fast or faster than vendors. Thus, we still see big account comprise and data exfiltration events occur almost daily.  

Successful ransomware operators have deep pockets and are investing heavily in building out their dev teams, automating exploitation of known vulnerabilities, and developing bespoke tools for account compromise and lateral movement as well as for more efficient data exfiltration. This problem is nowhere near being solved.

One thing remains true since the Yahoo data loss events: a determined attacker with ample resources will compromise a target sooner or later.  

In regard to ransomware operations, which are clearly one of the biggest problems organizations face today, the threat extends well beyond the immediacy of the interruption to operations.  

The sheer volume of data being exfiltrated is unprecedented. The number of class action lawsuits filed after breach events is increasing, and federal/state agencies are introducing more regulations on data governance that can come back to bite a victim organization.  

One thing that has certainly changed over the last decade is the liability for C-level and BoDs. Until very recently, even after a major breach event, everyone went home - but that may no longer be the case.  

Legal action targeting executive leaders at organizations following major breach events is more likely to land someone in prison than ever before. Legal action that names not just the companies but individual executives following the Uber breach and SolarWinds attacks demonstrate that executives are increasingly on the hook for lapses in security.  

Equally concerning - particularly the case with ransomware attacks - is the fact that the US government has not been able to protect organizations effectively against these attacks and data loss events.  

As such, we are increasingly seeing a trend where legal and regulatory actions simply revictimize the victims.  

It is more than likely that all of these issues will potentially get worse before they get better because in security, most often the best we can do is to try and stay one step behind the attackers and focus more efforts on early detection, disruption, and resiliency in the face of a successful attack. is the industry’s first dedicated, adaptive security platform that combines multiple advanced proprietary prevention engines along with AI models focused specifically on stopping ransomware – talk to a Halcyon expert today to find out more. Halcyon also publishes a quarterly RaaS and extortion group reference guide, Power Rankings: Ransomware Malicious Quartile.