NHI Email Exposure

Non-Human Identity (NHI) Email Exposure is a specific cybersecurity risk involving the discovery and unauthorized access to email addresses associated with automated systems, services, or functional roles within an organization, rather than specific human users.

What are NHI Emails?

NHI emails are typically **role-based or system-**use addresses that grant access to critical infrastructure, receive security alerts, or manage automation workflows. They are often invisible to traditional employee-focused security scans but hold high privileges. Examples include:

• Service Accounts: svc-prod-alert@company.com

• Administrative Roles: admin@company.com, security@company.com

• Operational Roles: system@company.com, ops@company.com

• Development Roles: devops@company.com, git@company.com

The Exposure Risk

The exposure risk arises when these addresses are publicly discoverable through external reconnaissance methods. Once discovered, they become a high-value target for adversaries because:

1. Credential Guessing: NHI addresses often use simple, predictable usernames (e.g., admin, support). An attacker can target these addresses with credential stuffing or brute-force attacks to compromise the associated passwords.

2. Targeted Phishing: The emails are often linked to services like cloud consoles, VPNs, or internal tools. Compromising a System or Security email can give an attacker direct access to sensitive alerts or management interfaces.

3. Vulnerability Chaining: An attacker might use the NHI email address to register for a third-party service, hoping the organization fails to monitor that inbox. They can then use a "forgot password" flow to gain control of that external account, potentially leading back to the organization's main infrastructure.

4. Disruption: Emails like Billing or Support can be hijacked to disrupt business operations, intercept customer communications, or access financial data.

In essence, NHI Email Exposure means an attacker has identified the operational keys to the kingdom, bypassing defenses that focus solely on individual employee accounts.

ThreatNG assists organizations in managing Non-Human Identity (NHI) Email Exposure by systematically discovering publicly exposed, role-based email addresses from an unauthenticated attacker's perspective, thereby identifying high-value targets for compromise.

ThreatNG's Role in NHI Email Exposure Management

External Discovery and Continuous Monitoring

ThreatNG performs purely external unauthenticated discovery to identify the organization's attack surface. This process is crucial for finding NHI email addresses that have been inadvertently exposed on the public internet. The platform Continuously Monitors the external attack surface, digital risk, and security ratings, ensuring that newly exposed NHI emails—or the presence of NHI emails on a freshly exposed asset—are detected immediately.

External Assessment and Examples

ThreatNG has a dedicated security rating for this risk:

• Non-Human Identity (NHI) Exposure Security Rating: This is a critical governance metric (A–F scale) that quantifies an organization's vulnerability to threats originating from high-privilege machine identities, such as leaked API keys, service accounts, and system credentials. Although the rating focuses on machine identities, the underlying NHI Email Exposure acts as a crucial vector. The rating's certainty is achieved through purely external, unauthenticated discovery to continuously assess 11 specific exposure vectors, including Sensitive Code Exposure and misconfigured Cloud Exposure.

  • Example: NHI Email addresses like system@company.com or devops@company.com are high-privilege targets. Suppose ThreatNG discovers this type of email on an exposed asset (e.g., a configuration file in a cloud bucket). In that case, it raises the overall NHI Exposure Security Rating due to the associated risk of a high-privilege account being targeted.

Investigation Modules and Examples

The following modules actively hunt for exposed NHI email addresses and their associated risk:

• NHI Email Exposure Module: This feature specifically groups all discovered emails by role, such as Admin, Support, Billing, Security, Info, Ops, System, test, user, account, devops, terraform, vpn, ssh, saas, and Integration. It provides a focused view of these high-value, non-human email addresses found within various findings categories:

  • Subdomains: An NHI email address (e.g., admin@test.company.com) is found in a plaintext link on a development subdomain.

  • Archived Web Pages: An old Admin Page or a TXT File from a decommissioned server, archived on the web, contains the ops@company.com email address.

  • Compromised Credentials: An NHI email address (e.g., service@company.com) is discovered in a batch of stolen credentials, confirming it is an active risk.

  • Website Control Files: An exposed Robots.txt file might inadvertently list Email Directories or Email Found, which include NHI emails. The Security.txt file may list a Security contact email.

• Domain Name Permutations: This module detects available and taken domain permutations and manipulations. It provides the Mail Record for these permutations. This helps identify which newly registered phishing domains are set up to impersonate an organization's NHI roles (e.g., the impersonator registers security-company.com and sets up a mail record to receive phishing responses).

• Dark Web Presence: This module identifies Associated Compromised Credentials. If an NHI email address is linked to compromised credentials on the dark web, it signifies an immediate threat.

Intelligence Repositories and Complementary Solutions

• Intelligence Repositories (DarCache):

  • Compromised Credentials (DarCache Rupture): This repository directly provides the intelligence needed to confirm if any of the discovered NHI emails have been exposed in a breach, enabling the organization to prioritize immediate password changes or key rotations for those accounts.

  • Dark Web (DarCache Dark Web): This tracks organizational mentions of related people, places, or things, including the context around leaked NHI emails or their associated accounts discussed by threat actors.

• Complementary Solutions:

  • Privileged Access Management (PAM) Systems: ThreatNG can identify exposed NHI emails and their context (e.g., found on a publicly visible config file). This information can be fed to a PAM system. The PAM system could then use this external discovery to locate the corresponding identity in its vault, flag it as a highly exposed asset, and automatically trigger a forced rotation of the credentials or keys associated with that email address.

  • Email Gateway and Filtering Solutions: The list of confirmed NHI emails identified by ThreatNG (e.g., git@company.com, billing@company.com) can be shared with an Email Gateway. The Gateway can then use this list to apply stringent filtering and multi-factor authentication requirements to all incoming and outgoing communication involving these critical accounts, reducing the phishing and spoofing risk identified via the NHI Email Exposure module.

  • Cybersecurity Asset Management (CSAM) Platforms: ThreatNG's discovery of NHI emails found on subdomains, archived pages, or in code can be added to the CSAM platform's inventory. The CSAM platform can then use this context to assign ownership for each exposed NHI email to a specific business unit or individual, ensuring accountability for remediation and proper securing of the account.