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. (such as?)

Alert Message

OS-OTHER Malicious DHCP server bash 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. Impact: CVSS base score 10.0 CVSS impact score 10.0 CVSS exploitability score 10.0 confidentialityImpact COMPLETE integrityImpact COMPLETE availabilityImpact COMPLETE Details: Ease of Attack:

What To Look For

Known Usage

No public information

False Positives

No known false positives

Contributors

Talos research team. This document was generated from data supplied by the national vulnerability database, a product of the national institute of standards and technology. For more information see [nvd].

MITRE ATT&CK Framework

Tactic:

Technique:

For reference, see the MITRE ATT&CK vulnerability types here: https://attack.mitre.org

CVE

CVE Additional Information

CVE-2014-6271
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.
Details
SeverityHIGH Base Score10.0
Impact Score10.0 Exploit Score10.0
Confidentiality ImpactCOMPLETE Integrity ImpactCOMPLETE
Availability ImpactCOMPLETE Access Vector
AuthenticationNONE Ease of Access
CVE-2014-6277
GNU Bash through 4.3 bash43-026 does not properly parse function definitions in the values of environment variables, which allows remote attackers to execute arbitrary code or cause a denial of service (uninitialized memory access, and untrusted-pointer read and write operations) 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. NOTE: this vulnerability exists because of an incomplete fix for CVE-2014-6271 and CVE-2014-7169.
Details
SeverityHIGH Base Score10.0
Impact Score10.0 Exploit Score10.0
Confidentiality ImpactCOMPLETE Integrity ImpactCOMPLETE
Availability ImpactCOMPLETE Access Vector
AuthenticationNONE Ease of Access
CVE-2014-6278
GNU Bash through 4.3 bash43-026 does not properly parse function definitions in the values of environment variables, which allows remote attackers to execute arbitrary commands 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. NOTE: this vulnerability exists because of an incomplete fix for CVE-2014-6271, CVE-2014-7169, and CVE-2014-6277.
Details
SeverityHIGH Base Score10.0
Impact Score10.0 Exploit Score10.0
Confidentiality ImpactCOMPLETE Integrity ImpactCOMPLETE
Availability ImpactCOMPLETE Access Vector
AuthenticationNONE Ease of Access
CVE-2014-7169
GNU Bash through 4.3 bash43-025 processes trailing strings after certain malformed function definitions in the values of environment variables, which allows remote attackers to write to files or possibly have unknown other impact 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. NOTE: this vulnerability exists because of an incomplete fix for CVE-2014-6271.
Details
SeverityHIGH Base Score10.0
Impact Score10.0 Exploit Score10.0
Confidentiality ImpactCOMPLETE Integrity ImpactCOMPLETE
Availability ImpactCOMPLETE Access Vector
AuthenticationNONE Ease of Access