The Age of Algorithms: How autonomous response AI is winning the race against time

Justin Fier, Director of Cyber Intelligence & Analytics | Thursday June 20, 2019

At a time when automated cyber-attacks execute at machine speed, the reality is that merely detecting these attacks is no longer sufficient to stop them before the damage is done. According to the Ponemon Institute’s oft-cited study on the topic, US companies take an average of 206 days to identify a data breach. And even when security teams discover a potential compromise the moment it begins, human professionals are fundamentally overmatched by malicious code that can encrypt or exfiltrate data in under a minute.

In this era of fast-acting threats, the only way forward is to fight code with code, to pit algorithm against algorithm, and to counter machine-speed attacks with machine-speed defenses. Darktrace, creator of the first enterprise-grade autonomous response technology, leverages AI algorithms to stop malware in its tracks, allowing incident responders to investigate and take action at their own pace. And critically, Antigena safeguards the digital estate day and night, weekend and holiday, because cyber-criminals don’t wait until business hours to strike.

Examined below are three sophisticated attacks that Antigena neutralized on behalf of security teams that were either out of office or unable to react in time. Collectively, they demonstrate that the future of autonomous cyber defense has already arrived.

Automated extortion, absent security team

The quintessential example of a cyber-threat too rapid for human professionals to parry, ransomware has become a top-of-mind concern for organizations around the world. In fact, previous research has found that approximately 70% of companies simply hand over the ransom upon getting hit, regardless of the cost. However, Darktrace autonomous response prevents ransomware from spreading by confining users and devices to their typical ‘patterns of life’. Rooted in a constantly refined understanding of ‘self’ versus ‘not self’, Darktrace AI surgically intervenes to shut off just the anomalous activity, while still allowing business operations to continue uninterrupted.

At 7:05 pm on a Friday, an employee at a large telecommunications firm accessed his personal email from a corporate smartphone and was tricked into downloading a malicious file that contained ransomware. Seconds later, the device began connecting to an external server on the Tor network — executing the attack just after the company’s security team had left the office for the weekend.

Darktrace AI, meanwhile, responded nine seconds after encryption began, raising a prioritized alert that called for immediate action. As the behavior persisted over the next few seconds, Darktrace activated AI-enabled autonomous response, which interrupted all attempts to write encrypted files before the ransomware spread across the telecom’s network. Critically, the autonomous response technology was on guard, even when the security team couldn’t be.

Antigena anticipates the alphabet

Nearly 95% of all successful cyber-attacks begin with a phishing email, which dupe employees into breaching their organizations before the security team realizes that anything is wrong. Even more difficult to catch are personalized “spear phishing” emails that use reconnaissance gathered from either social media or physical surveillance to impersonate trusted colleagues. Thwarting an advanced spear phishing campaign requires understanding normal behavior for each user well enough to flag subtly suspicious emails, as well as the ability to autonomously disable their malicious links — a combination that only Darktrace AI has achieved.

On the network of a major US city, a sophisticated spear phishing campaign managed to bypass the city’s native email controls. The attackers, who had obtained the city’s address book, were emailing recipients alphabetically, from “A” to “Z,” with ostensibly harmless emails that contained a malicious payload. Despite the well-disguised nature of this attack, Darktrace immediately flagged the domain linked in the emails as abnormal for the city’s employees, an action only possible with the evolving understanding of ‘self’ that Darktrace AI learns.

Darktrace autonomous response was deployed in ‘Passive Mode’ at the time, a trust-building setting that restricts the AI to communicating what it would have done in response to the threat rather than actually interceding. Interestingly enough, however, this nuance served to demonstrate the technology’s ability to stop attacks that conventional tools miss. Whereas Darktrace detected the campaign at the letter “A,” the city’s array of legacy tools finally woke up to the threat at “R.” In ‘Active Mode’, Antigena would have neutralized the attack before it reached a single user.

Serious threat at amusement park

Data exfiltration is among the most common objectives of cyber-criminals today, as stolen personal information and credentials can be sold on the Dark Web, used to commit identity theft, or leveraged to move laterally within a victim’s network. At a North American amusement park, an advanced attacker targeted an IoT device — a physical locker designed to store personal belongings — in an attempt to exfiltrate such data. As part of its default setting, the ‘smart’ locker regularly established contact with the supplier’s third-party online platform, a process that the attackers hijacked to compromise the device.

Once infiltrated, the locker started to transfer more than a gigabyte of unencrypted data across the network to a rare external site. The connections, which likely included identifying details and sensitive credentials, had the potential to be transmitted over the internet entirely unprotected — allowing the attackers to intercept the connections and use the information to breach the company’s network perimeter.

Due to the severity of the threat, Darktrace determined that an autonomous response was required. Within seconds, Darktrace AI took action by intelligently blocking all outgoing connections from the compromised locker. In doing so, it gave ample time for the security team to remove the smart locker from the internet — before any sensitive company or consumer data could be exfiltrated.

Making the red team wave the white flag with Darktrace AI

Michael Green, Lead Security Analyst at Cyberseer (Guest Contributor) | Monday June 3, 2019

The following guest-authored blog post examines how Cyberseer detected highly advanced red team activities with Darktrace’s Enterprise Immune System.

At Cyberseer, a managed security provider, our analysts know that thwarting sophisticated cyber-criminals requires being prepared for any eventuality. A red team attack today could easily be replicated by far less benign actors tomorrow, which is why we treat these exercises with the same gravity we would a genuine threat, employing the world’s most advanced AI cyber defenses like Darktrace to leave the bad guys without anywhere to hide.

Recently, one of our customers was involved in a red team assessment, partly as a means to see how their security team would react and contain the attack, and partly to determine the visibility of the different attack techniques across their security stack. During the engagement, the red team leveraged a number of stealthy “Living off the Land” (LotL) techniques. LotL refers to the malicious use of legitimate tools present on a system — such as PowerShell scripting, WMI, or PsExec — in order to execute attacks. It should be noted that these techniques are not just limited to red teamers: threat-actors are making use of such tools on compromised systems, a notable example being the 2017 Petya/NotPetya attack.

Here’s an example of how Cyberseer’s analysts used Darktrace to detect the red team, without prior knowledge of their techniques, in real time:

Invoke — Bloodhound

Created by professional penetration tester Andy Robbins, Bloodhound is an open source tool that uses graph theory to understand the relationships in an Active Directory (AD) environment. It can be harnessed to quickly gain deep insights into AD by enumerating all the computers for which a given user has admin rights, in addition to ascertaining group membership information. In the right hands, security teams can use Bloodhound to identify and then limit attack vectors. In the wrong hands, attackers can easily exploit these same pathways if left unaddressed.

To collect data, Bloodhound is complemented by a data ingestor called Sharphound, which comes either as a PowerShell script or an executable. Sharphound makes use of native Windows APIs to query and retrieve information from target hosts. For example, to enumerate Local Admin users, it calls ‘NetLocalGroupGetMember’ API to interact with the Security Account Manager (SAM) database file on the remote host.

These tools typically produce a number of artifacts that we would expect to see from the host device within network traffic:

  • Increase in connections to LDAP (389) and SMB (445) ports
  • Increase in connections to IPC$ shares
  • Increase in Distributed Computing Environment / Remote Procedure Calls (DCE_RPC) Connections to the following named pipes:
    • \PIPE\wkssvc - Query logged-in users
    • \PIPE\srvsvc - Query system information
    • \PIPE\svcctl - Query services with stored credentials
    • \PIPE\atsvc - Query scheduled tasks
    • \PIPE\samr - Enumerate domain and user information
    • \PIPE\lsass - Extract credential information

Associating this back to the red team engagement, upon execution of the Bloodhound tool the attacking device began reaching out to a large number of internal devices, causing a spike in internal connections:

Figure 1: Darktrace visualizing the increase in internal connections, with each dot representing a unique model breach triggered by Bloodhound activity.

In fact, the large volume of anomalous connections triggered a number of Darktrace’s behavioral models, including:

  • Anomalous Connection / SMB Enumeration
  • Anomalous Connection / New Service Control
  • Device / Network Scan
  • Device / Expanded Network Scan
  • Unusual Activity / Unusual Activity from Multiple Metrics
  • Unusual Activity / Sustained Suspicious Activity
  • Unusual Activity / Sustained Unusual Activity

Drilling deeper into these connections, it was possible to identify the named \PIPE\ connections that were detailed above:

Figure 2: Reviewing the raw connection logs within Darktrace’s Advanced Search.

Looking from top to bottom, we see scanning of devices on ports 139 and 445, access to remote IPC$ shares, SMB read / writes of the srvsvc, and samr pipes and lsass binds. Although these protocols have legitimate applications within a typical network, a device initiating so many of them within a short time frame warrants further investigation.

Darktrace AI not only shined a light on these activities, it automatically determined that they were potentially threatening despite being benign under most circumstances. Rooted in an ever-evolving understanding of our customer’s normal ‘pattern of life’, Darktrace correlated numerous weak indicators of anomalous behavior to flag the activity as a significant risk within seconds.

Invoke — PasswordSpray

“Password spraying” is an attack that targets a large number of accounts with a few commonly used passwords. In this case, for instance, the red team attempted to brute-force access to a file share. Although this tactic may seem rudimentary, a recent study by the NCSC found that 75% of organizations had accounts with passwords that featured in the top 1,000 passwords, while 87% had accounts with passwords that featured in the top 10,000.

Similar to the previous Bloodhound attack, the password spraying attack began with an increase in SMB connections on port 445. Darktrace alerted to even this relatively small number of connections, since it was anomalous for our customer’s unique network:

Figure 3: Volume of SMB session failures made to file shares from the attacker’s device.

Each of these connections was making use of a user credential and random password. From the logs below it is possible to see all of the SMB session failures:

Figure 4: A device event log showing repeated SMB session failures for each of the unsuccessful authentication attempts.

Even with only 50 total attempts seen, Darktrace quickly alerted upon both SMB enumeration and brute-force behaviors.

Both of these scenarios highlight the benefits of an AI-powered approach. Rather than focusing on hash or string matches for such tools, Darktrace is able to quickly identify anomalous patterns of behavior linked with their usage. This nuance is particularly critical in this case, given that all of these activities are not malicious in many situations. By differentiating between subtle threats and harmless traffic, Darktrace helps us defeat red teams and real criminals alike.