SID 1:46610

Rule Category

SERVER-MAIL -- Snort has detected traffic exploiting vulnerabilities in mail servers (such as Exchange, Courrier). These are different from protocol traffic, as this deals with the traffic going to the mail server itself.

Alert Message

SERVER-MAIL EHLO user overflow attempt

Rule Explanation

Rule checks for overly long EHLO SMTP messages used to exploit an off-by-one vulnerability present in the Exim mail transfer agent.

What To Look For

This event is generated when an attacker attempts to send an overly long EHLO SMTP message, used to exploit an off-by-one vulnerability present in the Exim mail transfer agent.

Known Usage

No public information

False Positives

No known false positives

Contributors

Cisco Talos Intelligence Group

Rule Groups

MITRE::ATT&CK Framework::Enterprise::Initial Access::Exploit Public-Facing Application

Adversaries may attempt to take advantage of a weakness in an Internet-facing computer or program using software, data, or commands in order to cause unintended or unanticipated behavior. The weakness in the system can be a bug, a glitch, or a design vulnerability. These applications are often websites, but can include databases (like SQL), standard services (like SMB or SSH), network device administration and management protocols (like SNMP and Smart Install), and any other applications with Internet accessible open sockets, such as web servers and related services.

MITRE::ATT&CK Framework::Enterprise::Privilege Escalation::Exploitation for Privilege Escalation

Privilege escalation includes techniques that allow an attacker to obtain a higher level of permissions on the mobile device. Attackers may enter the mobile device with very limited privileges and may be required to take advantage of a device weakness to obtain higher privileges necessary to successfully carry out their mission objectives.

CVE

CVE-2018-6789 CVE-2019-16928

Rule Vulnerability

Buffer Overflow

Buffer Overflows occur when a memory location is filled past its expected boundaries. Computer attackers target systems without proper terminating conditions on buffers, which then write the additional information in other locations in memory, overwriting what is there. This could corrupt the data, making the system behave erratically or crash. The new information could include malicious executable code, which might be executed.

CVE Additional Information

This product uses data from the NVD API but is not endorsed or certified by the NVD.

CVE-2018-6789

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CVE-2019-16928

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