Active Water Saci Campaign Spreading Via WhatsApp Features Multi-Vector Persistence and Sophisticated C&C

SUMMARY :

The Water Saci campaign has evolved, now utilizing an email-based command and control infrastructure and multi-vector persistence for resilience. The new attack chain employs script-based techniques, including VBS downloaders and PowerShell scripts, to hijack WhatsApp Web sessions and automate malware distribution. It features sophisticated remote control capabilities, allowing real-time management of infected machines as a coordinated botnet. The malware implements extensive anti-analysis measures and targets Portuguese-language systems. Its email-based C&C system uses IMAP connections to retrieve commands, complemented by an HTTP-based polling mechanism for ongoing communication. The campaign shares similarities with the Coyote banking trojan, suggesting possible links within the Brazilian cybercriminal ecosystem.

OPENCTI LABELS :

banking trojan,anti-analysis,vbs,coyote,sorvepotel


AI COMMENTARY :

1. Introduction The Active Water Saci campaign has entered a new phase of sophistication and resilience. Traditionally known for its ability to infiltrate systems using social engineering, this variant now leverages WhatsApp Web to propagate itself at scale. By blending multi-vector persistence mechanisms with a dual-channel command and control infrastructure, threat actors behind Water Saci have elevated their capabilities, posing a heightened risk to individuals and organizations alike. This article delves into the intricate details of the campaign, unpacking its attack chain, control systems, and noteworthy parallels with known banking trojans.

2. Attack Chain and Persistence Water Saci’s updated attack chain begins with the delivery of script-based payloads through WhatsApp messages that appear legitimate. Once the target interacts with a malicious link or attachment, a VBS downloader activates, pulling down additional components from a remote server. Subsequent PowerShell scripts then execute to establish persistence across system reboots and user profiles. The campaign’s multi-vector persistence strategy ensures that even if one component is removed, another remains to reestablish the infection, making eradication extremely challenging.

3. Sophisticated Command and Control Infrastructure Unlike its predecessors, the latest Water Saci variant employs an email-based C&C system that relies on IMAP connections to retrieve encrypted commands discreetly. In parallel, an HTTP-based polling mechanism ensures continuous two-way communication with the attackers’ servers. This hybrid approach provides redundancy, enabling the operators to maintain real-time control over an expanding botnet. The result is a coordinated network of compromised machines that can be orchestrated to execute complex tasks on demand.

4. Anti-Analysis and Targeting To evade detection and analysis, the malware integrates extensive anti-analysis techniques, such as sandbox checks, process hollowing, and code obfuscation. These measures slow down reverse engineering efforts and hinder automated security tools. Moreover, campaign artifacts indicate a specific focus on Portuguese-language systems, suggesting that threat actors are tailoring their social engineering and technical capabilities to exploit regional users and institutions.

5. Links to the Coyote Banking Trojan Security researchers have noted striking similarities between Water Saci’s infrastructure and the infamous Coyote banking trojan. Both families share overlapping code snippets, email-based C&C patterns, and even domain registration profiles. These correlations point to a possible connection within the Brazilian cybercriminal ecosystem, hinting at collaboration or code sharing among threat groups. The convergence of these tools amplifies the overall threat landscape and underscores the adaptability of regional attackers.

6. Implications and Recommendations The resurgence of Water Saci with enhanced multi-vector persistence and dual-channel C&C underscores the critical need for organizations to adopt layered defenses. Security teams should monitor unusual IMAP traffic and HTTP polling behavior, deploy advanced threat detection for script-based attacks, and educate users about the dangers of unsolicited WhatsApp links. Proactive threat hunting and regular system audits will help identify early indicators of compromise and disrupt the campaign before it gains a foothold.


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Active Water Saci Campaign Spreading Via WhatsApp Features Multi-Vector Persistence and Sophisticated C&C