CISA published an advisory (AA26-237A) documenting two simultaneous red team assessments at critical infrastructure organizations. Both organizations lost full domain control and had their cloud environments compromised. One of them didn’t know until CISA told them afterward.
“The Cybersecurity and Infrastructure Security Agency (CISA) conducted simultaneous red team assessments at two organizations and observed different defensive outcomes. In both environments, the red team achieved full domain compromise and accessed sensitive business systems (SBSs) and cloud resources.” states CISA. “Organization A failed to detect or contain the activity, but Organization B rapidly identified initial compromise attempts, isolated affected systems, and forced the red team into an assume breach model.”
Organization A is a Government Services and Facilities Sector entity. Organization B operates in the Water and Wastewater Systems Sector. The red team used comparable techniques against both. The difference in outcome was entirely about detection and response, not the sophistication of the attack.
At Organization A, the red team found a web application that still used default credentials. They used it to send phishing emails from a trusted internal address and gained access to four workstations. From there, they exploited a misconfigured Active Directory Certificate Services template with the ESC1 flaw. This allowed a low-privileged user to request certificates for other users, including administrators. They then reached all the targeted sensitive business systems without anyone noticing. After moving into the cloud, they even read SOC staff emails to see if the attack had been detected. It hadn’t.
“Without well-defined baselines and alert filtering, false positives and routine alerts overwhelm defenders, obscuring real threats.” CISA continues. “Organizations that tune alerts to highlight anomalies and filter out normal business activity enable defenders to focus on genuine incidents and respond rapidly.”
Organization A’s SOC was receiving thousands of false positive alerts, many at higher severity than the actual intrusion alerts the red team was generating. Staff eventually reviewed SCCM-related alerts from real red team activity, couldn’t identify the system’s owner or function, and marked it a false positive.
The red team confirmed the miss by reading SOC email. Then they used keyloggers and screenshot capture on SOC workstations to make sure nothing was coming. Nothing was. The organization had multiple separate SOCs with different EDR solutions and no cross-team visibility, which meant that even if one team noticed something, there was no mechanism to act on it across the relevant systems.
“Detection tools are only as effective as the people, processes, and procedures supporting them. SOC staff should not operate in silos and should have clear authority unhindered by bureaucracy to effectively contain and resolve incidents.” add CISA.
At Organization A, SOC analysts were managing systems they didn’t fully understand and had no written escalation procedures, so their default response to ambiguity was to wait. At Organization B, staff triaged, investigated, coordinated with engineering, and reimaged machines before handing them back to users.
At Organization B, the red team still found important security gaps. They discovered a password stored in plain text inside an XML file on an SCCM distribution point. They used the related service account to gain powerful rights over a domain controller and then performed a DCSync attack, obtaining the krbtgt
hash. This allowed them to create Golden Tickets and impersonate users across the domain.
They also found a path into the OT network through RDP files pointing to a bastion host. Using FTP credentials found on a jump server, they connected to the bastion through SSH. The bastion had no outbound internet access, so their payload could not run, and the SOC quarantined the host. Still, the access path was there.
Both organizations also had the same cloud security problem: neither had enabled Conditional Access for workload identities. This Microsoft feature applies access controls to applications and service accounts, not just human users. Without it, applications with broad Microsoft Graph permissions can bypass normal Conditional Access rules. CISA’s red team used this gap in both organizations to access emails across the companies.
In Organization A, the team also found AWS IAM credentials stored in users’ home directories with no expiration date. Those credentials could remain valid indefinitely, creating another long-term risk.
In Organization B’s cloud environment, the red team abused Seamless SSO by using Kerberos tickets obtained via DCSync to authenticate to Azure without needing any user’s cleartext password. They found a disabled AD-synced account that owned an application with permission to read, write, and send emails for every user in the tenant. They re-enabled the account, DCSynced its credentials, added a client secret to the application, and could then access the full mailbox of every employee from the public internet. Organization B’s detections flagged the AzureHound tool by user agent and caught anomalous Microsoft Graph API request volumes, but those controls arrived after the initial cloud access was already established.
CISA recommends several practical steps to improve security. These include hardening ADCS by disabling CT_FLAG_ENROLLEE_SUPPLIES_SUBJECT
on templates and limiting who can enroll, setting the Machine Account Quota to zero when there is no operational need, and removing cleartext credentials from workstations and network shares.
Organizations should also enable Conditional Access for workload identities, create procedures to revoke tokens, and treat SCCM and similar endpoint management platforms as Tier 0 assets, giving them the same level of protection as domain controllers.
The full advisory also maps each red team technique to its MITRE ATT&CK identifier and compares how well the two organizations detected the different stages of the attacks.
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