The threat known as Illuminating Transparent Tribe pertains to an advanced persistent threat (APT) group identified as Transparent Tribe or APT36. This analysis focuses on uncovering the infrastructure supporting their operations through passive DNS data and host response history. The investigation began with indicators from a CyberXTron report detailing a targeted phishing campaign against Indian government and defense entities. Using DNS history and IP pivoting techniques, researchers identified shared name server patterns and non-Cloudflare IP addresses linked to Transparent Tribe's infrastructure. Additionally, ETag pivoting—a technique leveraging HTTP response headers—was employed to discover previously unreported domains exhibiting similar subdomain naming conventions to known Transparent Tribe assets. The domains and IPs identified, such as 37.221.64.252 and several mgovcloud.in subdomains, suggest the use of deceptive cloud-related domain names to facilitate phishing and potentially other malicious activities. The campaign leverages multiple tactics consistent with MITRE ATT&CK techniques T1583 (Acquire Infrastructure), T1592 (Gather Victim Network Information), T1589 (Gather Victim Identity Information), T1590 (Gather Victim Org Information), and T1598 (Phishing). The methodology highlights the effectiveness of combining passive DNS data with host response history to map out hidden threat infrastructure, which is critical for proactive defense and threat hunting. Notably, no known exploits targeting software vulnerabilities are reported, indicating the threat primarily relies on social engineering and infrastructure obfuscation rather than direct software exploitation.

For European organizations, the direct impact of this threat is currently limited given the primary targeting of Indian government and defense sectors. However, the techniques and infrastructure discovery methods used by Transparent Tribe could be adapted or expanded to target European entities, especially those involved in defense, government, or critical infrastructure sectors. The use of phishing campaigns leveraging cloud-themed domains could deceive employees into credential theft or malware deployment, potentially leading to data breaches, espionage, or disruption of operations. The presence of sophisticated infrastructure and evasion techniques such as ETag pivoting indicates a high level of operational security, making detection and mitigation more challenging. European organizations with partnerships or data exchanges with Indian entities or those operating in similar sectors should be vigilant. Additionally, the campaign's focus on infrastructure acquisition and reconnaissance suggests potential for future escalation or targeting of new regions, including Europe.

European organizations should implement targeted defenses against phishing campaigns that mimic legitimate cloud service domains. This includes deploying advanced email filtering solutions capable of detecting domain spoofing and suspicious subdomain patterns similar to those identified (e.g., mgovcloud.in.*). Network defenders should incorporate passive DNS monitoring and historical DNS analysis into their threat hunting processes to identify suspicious domain registrations and infrastructure overlaps. Utilizing HTTP header analysis, including ETag values, can help detect anomalous host responses indicative of threat actor infrastructure. Organizations should conduct regular employee training focused on recognizing sophisticated phishing attempts, especially those involving cloud service impersonation. Multi-factor authentication (MFA) must be enforced to limit the impact of credential theft. Collaboration with national cybersecurity centers to share intelligence on emerging APT infrastructure and phishing campaigns is recommended. Finally, organizations should maintain updated threat intelligence feeds that include indicators related to Transparent Tribe and similar APT groups to enable timely blocking and investigation.