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The CVE-2024-20401 vulnerability exists within the Advanced Malware Protection feature of Cisco Secure Email Gateway.
It stems from improper handling of email attachments when file reputation and analysis services are enabled.
An unauthenticated remote attacker can exploit this flaw by sending a specially crafted malicious email attachment.
The affected device processes the incoming email stream via the Content Scanner Tools component.
Insecure parsing routines fail to properly sanitize file paths and names within the attachment structure.
This validation failure allows the attacker to write arbitrary files directly to the underlying operating system filesystem.
Because the scanning processes execute with high system privileges, arbitrary file writing leads directly to root control.
Attackers can overwrite system binaries, inject malicious configuration parameters, or create unauthorized root users.
No prior authentication or user interaction is required to launch this network-based attack vector successfully.
The vulnerability impacts deployments running vulnerable Cisco AsyncOS software combined with older Content Scanner Tools.
Specifically, tool versions earlier than 23.3.0.4823 combined with enabled incoming mail policies expose the appliance.
Successful exploitation grants full administrative control and potential persistent access over the targeted hardware gateway.
Organizations must quickly identify affected mail policies and ensure proper security software updates are applied.
Without immediate mitigation, remote code execution compromises the confidentiality, integrity, and availability of communications.
This mechanism highlights the architectural risks inherent in deep content inspection engines handling untrusted files.
Securing the appliance requires updating both the core operating system and the specific scanner tools package.
The flaw remains a textbook example of insecure file write vulnerabilities leading to complete system takeover.
Attack payload delivery happens transparently during routine mail transfer agent processing cycles.
File analysis features inspect inbound files by passing them to underlying scanning subcomponents.
Inadequate boundary checks allow path traversal tokens inside archive or document metadata headers.
The unpacking routine interprets these traversal tokens and deposits payload bytes outside secure temporary directories.
Overwriting critical system files alters runtime execution flow during subsequent administrative operations or reboots.
Threat actors leverage this predictable file placement to plant backdoor scripts or SSH keys.
The impact spans both virtualized cloud deployments and physical email security appliances uniformly.
Cisco Security Intelligence tracks and publishes advisories to assist administrators in identifying vulnerable versions.
Timely patching remains the sole definitive defense against this critical vulnerability class.
System logs may display anomalous behavior or unexpected configuration modifications following successful compromise attempts.
DailyCVE Form:
Platform: Cisco Gateway
Version: AsyncOS patches
Vulnerability: File write
Severity: Critical level
date: July 2024
Prediction: July 2024
What Undercode Say:
Check Content Scanner version version Verify Advanced Malware Protection grep -i "file analysis" /etc/esa/config.xml Update Content Scanner Tools upgrade
Exploit: (Educational Purposes!)
An attacker crafts a malicious email attachment containing directory traversal sequences targeting sensitive directories. When the Cisco Secure Email Gateway processes this message with File Analysis enabled, the vulnerable Content Scanner Tools component unpacks the file without path sanitization. Consequently, the payload writes an arbitrary file onto the underlying filesystem. By targeting critical system binaries or SSH keys, the attacker escalates privileges to root and achieves complete remote command execution.
Protection: from this CVE
Upgrade the Content Scanner Tools package to version 23.3.0.4823 or later.
Update Cisco AsyncOS software to release 15.5.1-055 or later.
Ensure automatic updates for security services are enabled in the web interface.
Restrict management access to trusted internal networks and implement robust access controls.
Impact:
Unauthenticated remote attackers can write arbitrary files on the underlying operating system.
Execution of commands with root privileges occurs successfully.
Attackers can add users with root privileges, modify device configurations, or cause permanent denial of service conditions.
Full system compromise threatens the confidentiality, integrity, and availability of enterprise email infrastructure.
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Sources:
Reported By: www.cve.org
Extra Source Hub:
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