Click. Notify. Exfiltrate. Why the Most Damaging Threats Start in Your Inbox

Click. Notify. Exfiltrate. Why the Most Damaging Threats Start in Your Inbox

By HaystackID Staff

When organizations face a security breach, internal misconduct, or a regulatory inquiry, the instinct is often to focus on the latest digital platforms, such as Slack messages, Teams threads, and ephemeral chats. These channels feel immediate and modern, reflecting how we work today. However, in the rush toward the future, investigators can overlook a timeless and invaluable data source: email.

Despite its longstanding role as the backbone of business communication, email is frequently underestimated compared to newer tools. This oversight is a mistake. In many cases, email quietly holds the evidence, undetected, unencrypted, and fully admissible. It’s where systems send security alerts, banks issue access codes, and cloud services confirm logins. Essentially, email is the digital paper trail, and sometimes, it’s the trail’s starting point and its end.

“Just as we’ve had to adapt our approach with mobile devices and computers, we’ve also had to adjust how we handle email. That said, email has been largely overlooked, and it’s something that’s been around for a very long time,” said Rene Novoa, CCLO, CCPA, CJED Vice President of Forensics at HaystackID®, during a recent webcast, “Faster Finds, Fewer Files: A Smarter Approach to Email Investigations.”

One reason for this oversight? The proliferation of team collaboration platforms. From Slack and Microsoft Teams to Zoom Chat and WhatsApp, communication is now fragmented across multiple tools. However, John Wilson, ACE, AME, CBE, HaystackID’s Chief Information Security Officer and President of Forensics, cautioned against dismissing the relevance of email.

“There is a shift toward people moving from email to Slack and Teams chats,” Wilson said during the webcast. “But many of those platforms’ communications still end up in email. Slack, for example, still sends notifications and message summaries to your inbox, including the messages themselves. So, a lot of that information is still accessible through email.”

In other words, ignoring email during investigations means potentially missing more than you realize.

Why Email Remains an Investigator’s Goldmine

Consider the last time you logged into a new device or reset your password. Chances are, you received an email, whether it was a verification code from your bank, an alert from iCloud asking if that login was you, or a confirmation that a new device accessed your account. These small messages are more than digital clutter; they’re clues. And in digital investigations, clues are everything.

Email continues to be one of the most reliable artifacts of intent and identity. It documents what happened, when, and who was involved, even if someone tries to cover their tracks. This is especially crucial in investigations where individuals may deliberately hide their activities.

“So much of what we do can be traced back to email, whether that’s a nugget of information about system access or approval,” explained Novoa. “That information can be very valuable, especially if someone is trying to conceal something or if they’ve signed up for certain repositories.”

Often, the most revealing details aren’t in what was explicitly said but in the signals surrounding it. Wilson recalled a complex case involving a departing employee suspected of stealing proprietary data. Initially, there were no red flags; standard monitoring tools detected no suspicious activity. However, a closer look at the employee’s email revealed a pattern: two-factor authentication messages related to a cloud storage site.

“The only way we knew about that site was through his email and the two-factor authentication codes he received,” Wilson said. “That led us to discover that he was using the site for data exfiltration, something that wouldn’t have been apparent otherwise.”

The situation was even more complicated because the employee had been uploading sensitive data from shared office terminals, making attribution difficult. No alarms had been triggered, and the site wasn’t on any blocklist. The exfiltration flew under the radar.

“It was a carefully crafted setup to bypass data loss prevention tools,” Wilson explained. “But it was only because of the two-factor authentication emails in his inbox that we uncovered the activity.”

What could have been a dead end became a breakthrough thanks to the humble inbox.

The Weight of History (and Mailboxes)

To understand why email investigations are often overlooked or mismanaged, it’s important to consider their history. In the early days of digital forensics, the default approach was straightforward: collect the entire mailbox. This was necessary to ensure nothing was missed, especially since many systems didn’t properly index all data, and crucial file types could easily be overlooked. However, that approach, once essential, has become unsustainable.

Email has evolved dramatically. What was once a simple stream of short, plain-text messages has transformed into a complex web of HTML-rich designs, embedded images, large file attachments, and sprawling conversation threads. Today’s inboxes are not only larger but also far more intricate, making them harder to parse and significantly more expensive to process at scale.

The challenge isn’t solely the volume of data; it’s what comes after collection. Once you pull a full mailbox, you must process, filter, search, and analyze it. Alongside this, legal considerations such as privilege and privacy add layers of complexity.

Many standard tools, like Google Vault or built-in enterprise search features, aren’t designed to surface everything investigators need. Relying solely on these tools can lead to missing critical details. That’s why modern investigators are seeking smarter, more targeted methods to manage email volume without sacrificing visibility. The old methods are no longer sufficient; the stakes are too high to rely on outdated workflows.

The Rising Threat of BEC

While email continues to be the backbone of modern investigations, it also serves as the frontline for some of today’s most damaging cybercrimes. Business Email Compromise (BEC) has evolved from crude phishing schemes into highly sophisticated, financially devastating attacks. Often, the inbox becomes both the target and the evidence trail.

Once attackers gain access to a mailbox, they tend to observe quietly. They study communication styles among executives, analyze how projects are discussed, and even use artificial intelligence to mimic tone, vocabulary, and timing, making their fraudulent emails indistinguishable from genuine correspondence.

“They understand the vernacular, how you speak to your CEO, your CFO, and other key personnel,” Wilson said. “Because they’re analyzing all that communication using AI to impersonate those individuals.”

The financial impact of BEC is staggering. While globally responsible for billions in losses, the average loss per successful incident is eye-opening.

“They’re now averaging almost $300,000 per incident,” Wilson said. “This isn’t just about large-scale fraud; it’s about targeted schemes, getting someone to transfer money, buy gift cards, or wire funds for a specific purpose. It’s incredibly precise.”

And once the money is gone, recovery is urgent. In BEC cases, timing is everything. It’s not just about understanding what happened; it’s about detecting it quickly enough to stop or mitigate the damage.

“I received a statistic from the Secret Service’s cybercrime task force I work with,” Novoa shared. “They said that if you don’t take action within 72 hours, the money is typically lost. Organizations need the right workflows and experts in place to detect these threats early because detection is the hardest part. You need the technology to respond swiftly.”

The Case for Triage-First Email Investigations

In modern investigations, effectively identifying pertinent information quickly and efficiently is crucial. Consequently, many teams are shifting from collecting entire mailboxes toward a targeted, prioritized approach that emphasizes relevance and rapid decision-making.

This strategy helps protect privacy, reduce costs, and prevent forensic teams from being overwhelmed by irrelevant data. Investigators can focus on the most important elements: key custodians, communication patterns, and critical timelines.

This philosophy underpins HaystackID’s READI™ for Email, our recent enhancement to our Remote Endpoint Analysis and Data Intelligence Suite. Designed to enable targeted, defensible, and rapid email investigations, READI for Email allows investigators to preview, filter, and triage emails immediately across platforms like Microsoft 365 and Google Workspace without waiting for full mailbox ingestion.

“Email investigations have traditionally been cumbersome, costly, and slow,” Wilson noted in the press release. “READI for Email addresses these challenges directly, allowing investigators to analyze email data upfront, identify key evidence quickly, minimize unnecessary data handling, and better manage compliance risks.”

Security and privacy are integral to its architecture. READI for Email features encrypted communication protocols, token-based authentication, fine-grained access controls, and encryption of all data in motion and at rest, supporting compliance with regulations such as GDPR, CCPA, and HIPAA.

The tool’s versatility spans many use cases: insider threat detection, login anomaly monitoring, email policy audits, and administrative activity reviews. Investigators can verify policy enforcement, identify potential misuse, and collect only relevant data, all while maintaining a defensible chain of custody.

“Given the increasing volume of email data and the sophistication of digital threats, READI for Email enables forensic and legal teams to respond more efficiently and effectively,” Novoa said in the release.”It streamlines the identification of relevant information, shortens investigative timelines, and enhances overall organizational security.”

At its core, this approach signifies a shift toward modernizing how investigations are conducted.

“That’s really where we see things heading,” Wilson said during the webcast. “The ability to quickly identify key information through a triage-level process is what drives our success. It’s about doing more with less, faster, smarter, and more accurately.”

Ultimately, this isn’t just about improving investigations; it’s about achieving better outcomes: faster answers, reduced costs, and more informed decisions.

Learn how READI for Email can help your organization focus on the most impactful data first and enhance your investigative effectiveness.

Assisted by GAI and LLM technologies.

SOURCE: HaystackID