InfoSecBulletin Cybersecurity for mankind
Cisco has confirmed that a serious zero-day vulnerability allowing remote code execution is being actively exploited in its Secure Email Gateway and Secure Email and Web Manager appliances.
The CVE-2025-20393 flaw lets unauthorized attackers run arbitrary root commands by sending specific HTTP requests to the Spam Quarantine feature. Cisco aware of the attacks on December 10, 2025, with signs of exploitation beginning in November 2025.
Citrix NetScaler SAML 0-Day Flaw Under Attack
Major Danish university breached, 200,000 users at risk
Microsoft’s X account hijacked to promote Clippy crypto scam
Critical cPanel, GitLab AI Gateway and Dell CSM Flaws Enable RCE And Admin Hijacking
Nearly 100,000 email addresses exposed in first AI-related data breach in Singapore
Hackers Exploit Zimbra Mail Servers: TeamViewer patched 5 critical flaws
Google Warns of Hackers Actively Exploiting Citrix 0-Day Flaws
CISA Warns Critical MikroTik RouterOS Flaw While Cisco SD-WAN Zero-Day Exploited in Attacks
Apple Zero-Day Exploited: Pentagon Data Breach Reportedly Exposes Sensitive Data of 3 Million People
JadePuffer Agentic AI targets and destroys Azure’s cloud resources
Exploitation Campaign and Threat Actor:
Cisco Talos believes the campaign is linked to UAT-9686, a China-based advanced threat group, with moderate confidence due to similarities with APT41 and UNC5174.
Attackers use a Python backdoor named AquaShell for ongoing remote access, along with tools like AquaTunnel and Chisel for internal movement, and AquaPurge to clear logs and avoid detection. Their main targets are telecommunications and critical infrastructure, emphasizing espionage over ransomware.
Mitigation and Fixed Releases:
Cisco Secure Email Gateway Fixed Releases
| Vulnerable Release | First Fixed Release |
|---|---|
| 14.2 and earlier | 15.0.5-016 |
| 15.0 | 15.0.5-016 |
| 15.5 | 15.5.4-012 |
| 16.0 | 16.0.4-016 |
Cisco Secure Email and Web Manager Fixed Releases
| Vulnerable Release | First Fixed Release |
|---|---|
| 15.0 and earlier | 15.0.2-007 |
| 15.5 | 15.5.4-007 |
| 16.0 | 16.0.4-010 |
Cisco released patches to fix the vulnerability and eliminate known persistence methods; there are no workarounds. Administrators must upgrade immediately and check Spam Quarantine status in the web interface under Network > IP Interfaces.
