Rule Document 1:31976

Rule Category

OS-OTHER -- Snort has detected traffic targeting vulnerabilities in a non-standard operating system (not Windows, Linux, Solaris, or mobile). This does not include browser traffic or other software on the OS, but attacks against the OS itself.

Alert Message

OS-OTHER Bash CGI environment variable injection attempt

Rule Explanation

GNU Bash through 4.3 processes trailing strings after function definitions in the values of environment variables, which allows remote attackers to execute arbitrary code via a crafted environment, as demonstrated by vectors involving the ForceCommand feature in OpenSSH sshd, the mod_cgi and mod_cgid modules in the Apache HTTP Server, scripts executed by unspecified DHCP clients, and other situations in which setting the environment occurs across a privilege boundary from Bash execution, aka "ShellShock." NOTE: the original fix for this issue was incorrect; CVE-2014-7169 has been assigned to cover the vulnerability that is still present after the incorrect fix.

What To Look For

This rule will alert when an attempt to exploit a known command injection vulnerability in Bash is detected.

Known Usage

No public information

False Positives

No known false positives

Contributors

Cisco Talos Intelligence Group

Rule Groups

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.

Vulnerability::Severity::Critical

Vulnerability::Severity::High

CVE

CVE-2014-6271 CVE-2014-6277 CVE-2014-6278 CVE-2014-7169

Rule Vulnerability

Command Injection

Command Injection attacks target applications that allow unsafe user-supplied input. Attackers transmit this input via forms, cookies, HTTP headers, etc. and exploit the applications permissions to execute system commands without injecting code.

CVE Additional Information

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

CVE-2014-6271

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CVE-2014-6277

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CVE-2014-6278

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CVE-2014-7169

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