Rule Category

INDICATOR-COMPROMISE -- Snort detected a system behavior that suggests the system has been affected by malware. That behavior is known as an Indicator of Compromise (IOC). The symptoms could be a wide range of behaviors, from a suspicious file name to an unusual use of a utility. Symptoms do not guarantee an infection; your network configuration may not be affected by malware, but showing indicators as a result of a normal function. In this case, attackers may be attempting to gain privileges and access other systems, spread influence, and make calls and commands with elevated access. The context of the traffic is important to determine intrusion; traffic from an administration utility performing commands on a user's computer is likely not a compromise, but a user laptop accessing a webserver may indicate intrusion.

Alert Message

INDICATOR-COMPROMISE command error

Rule Explanation

This event is generated by an unsuccessful attempt to execute a command. This may be indicative of post-compromise behavior indicating the use of a Windows command shell. Impact: Serious. An attacker may have the ability to execute commands remotely Details: This event is generated by an unsuccessful attempt to execute a Windows command which generates the response "Bad command or filename". For example, it is generated by the Windows operating system if the executable file to be run from the command line is not found. Seeing this response in HTTP traffic indicates that an attacker may have been able to spawn a shell bound to a web port and has tried to execute a command. Note that the source address of this event is actually the victim and not that of the attacker. Ease of Attack: Simple. This post-attack behavior can accompany different attacks.

What To Look For

No information provided

Known Usage

No public information

False Positives

Known false positives, with the described conditions

This rule will generate an event if the string "Bad command or filename" appears in the content distributed by a web server, in which case the rule should be tuned.

Contributors

Cisco Talos Intelligence Group

Rule Groups

No rule groups

CVE

None

Rule Vulnerability

No information provided

CVE Additional Information

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

None