AT&T Breach Incident Score: Analysis & Impact (ATT1764820523)

In this Rankiteo incident briefing, we review the AT&T breach identified under incident ID ATT1764820523.

The analysis begins with a detailed overview of AT&T's information like the linkedin page: https://www.linkedin.com/company/att, the number of followers: 1591781, the industry type: Telecommunications and the number of employees: 177538 employees

After the initial compromise, the video explains how Rankiteo's incident engine converts technical details into a normalized incident score. The incident score before the incident was 543 and after the incident was 474 with a difference of -69 which is could be a good indicator of the severity and impact of the incident.

In the next step of the video, we will analyze in more details the incident and the impact it had on AT&T and their customers.

AT&T recently reported "AT&T Data Breaches Settlement", a noteworthy cybersecurity incident.

Millions of AT&T customers were affected by two data breaches in 2019 and 2024, leading to the exposure of personal information.

The disruption is felt across the environment, and exposing Personal information including Social Security numbers, birth dates, and legal names, with nearly 73 million records at risk, plus an estimated financial loss of $177 million settlement.

In response, and stakeholders are being briefed through Public disclosure and settlement announcement.

The case underscores how Settled, with advisories going out to stakeholders covering Compensation claims open until Dec. 18, 2025.

Finally, we try to match the incident with the MITRE ATT&CK framework to see if there is any correlation between the incident and the MITRE ATT&CK framework.

The MITRE ATT&CK framework is a knowledge base of techniques and sub-techniques that are used to describe the tactics and procedures of cyber adversaries. It is a powerful tool for understanding the threat landscape and for developing effective defense strategies.

Rankiteo's analysis has identified several MITRE ATT&CK tactics and techniques associated with this incident, each with varying levels of confidence based on available evidence. Under the Initial Access tactic, the analysis identified Trusted Relationship (T1199) with moderate to high confidence (70%), with evidence including data breaches in 2019 and 2024, and customer data spreading on the dark web and Exploit Public-Facing Application (T1190) with moderate confidence (60%), supported by evidence indicating attack vector and vulnerability not disclosed. Under the Exfiltration tactic, the analysis identified Transfer Data to Cloud Account (T1537) with moderate confidence (50%), supported by evidence indicating data spreading on the dark web and Exfiltration Over C2 Channel (T1041) with moderate to high confidence (80%), with evidence including data exfiltration such as Yes (dark web), and 73 million records exposed. Under the Credential Access tactic, the analysis identified Cloud Instance Metadata API (T1552.005) with moderate confidence (50%), with evidence including telecommunications industry targeted, and high-sensitivity data compromised. Under the Impact tactic, the analysis identified Data Encrypted for Impact (T1486) with lower confidence (30%), supported by evidence indicating no ransomware details disclosed and Data Destruction (T1485) with lower confidence (40%), with evidence including identity theft risk such as Yes, and legal liabilities such as Yes. These correlations help security teams understand the attack chain and develop appropriate defensive measures based on the observed tactics and techniques.