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 modcgi and modcgid 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.

A flaw was found in the bash functionality that evaluates specially formatted environment variables passed to it from another environment. An attacker could use this feature to override or bypass restrictions to the environment to execute shell commands before restrictions have been applied. Certain services and applications allow remote unauthenticated attackers to provide environment variables, allowing them to exploit this issue.

Acknowledgements:

Red Hat would like to thank Stephane Chazelas for reporting this issue.

Ruby vSphere Console (RVC) in VMware vCenter Server Appliance allows remote authenticated users to execute arbitrary commands as root by escaping from a chroot jail.

VMware vCenter Server Appliance (vCSA) 5.1 before Update 1 allows remote authenticated users to create or overwrite arbitrary files, and consequently execute arbitrary code or cause a denial of service, by leveraging Virtual Appliance Management Interface (VAMI) web-interface access.

VMware vCenter Server Appliance (vCSA) 5.1 before Update 1 allows remote authenticated users to execute arbitrary programs with root privileges by leveraging Virtual Appliance Management Interface (VAMI) access.