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CRITICAL Published July 24, 2026

Operation RoundPress Rolls on with More Half-Click Webmail Zero-Days

TA458, a Russia-aligned espionage group likely linked to GRU, continues exploiting half-click cross-site scripting vulnerabilities in webmail platforms to steal sensitive email data. These exploits require no user interaction beyond opening the malicious email in webmail. The actor exploited multiple zero-days including SOGo (CVE-2026-8496), Zimbra (CVE-2025-27915), and mDaemon (CVE-2025-3929), alongside n-day Roundcube vulnerabilities. TA458 deploys SpyPress malware, an obfuscated JavaScript-based tool customized for each targeted mailserver, stealing credentials, contacts, and emails. The group primarily targets Ukrainian government entities and Eastern European military installations across Albania, Greece, Moldova, and Türkiye, with occasional focus on chemical, telecommunications, and technology sectors. Recent variants include backdoor mechanisms for persistent access through reverse shells and webshells.

TA458, a Russia-aligned espionage group likely linked to GRU, continues exploiting half-click cross-site scripting vulnerabilities in webmail platforms to steal sensitive email data. These exploits require no user interaction beyond opening the malicious email in webmail. The actor exploited multiple zero-days including SOGo (CVE-2026-8496), Zimbra (CVE-2025-27915), and mDaemon (CVE-2025-3929), alongside n-day Roundcube vulnerabilities. TA458 deploys SpyPress malware, an obfuscated JavaScript-based tool customized for each targeted mailserver, stealing credentials, contacts, and emails. The group primarily targets Ukrainian government entities and Eastern European military installations across Albania, Greece, Moldova, and Türkiye, with occasional focus on chemical, telecommunications, and technology sectors. Recent variants include backdoor mechanisms for persistent access through reverse shells and webshells.

MITRE ATT&CK

Tactics, Techniques & Procedures

TA0011 Command and Control tactic
TA0001 Initial Access tactic
TA0008 Lateral Movement tactic
TA0003 Persistence tactic

Defensive mapping

Mapped controls

The audit will verify each of these controls is in place and effective.

Control Confidence Why it matters
EDR with behavioural detection suggested 75% Recommended control for apt
Network segmentation between user and server tiers suggested 75% Recommended control for apt
PAM suggested 75% Recommended control for apt
Threat hunting suggested 75% Recommended control for apt
Log retention and SIEM suggested 75% Recommended control for apt