Bash “Shellshock” vulnerability

Advisory ID CVE Number Date discovered Severity Advisory revision
STORM-2014-001 CVE-2014-6271 09/25/2014 medium v1

Vulnerability details

A vulnerability has been disclosed in the bash command interpreter (CVE-2014-6271). Its exploitation could lead to a remote code execution on the targeted system.

Impacted products

ProductsSeverityDetail
Fast360 medium The version of the bash interpreter on Fast360 appliances is vulnerable. At the time of writing, preliminary studies showed that this vulnerability may be exploited only with a non-standard configuration of the DHCP client (« cable interface » with arkoonconfig key "dhcp-client.get-dns-servers=yes"), with conditions different from the attacks available on Internet. However, due to the central role of bash, other non-identified vectors may be discovered allowing to exploit this vulnerability. A preventive update is scheduled for Fast360 as soon as possible.

Revisions

Version Date Description
v1 09/25/2014 Initial release


Fast360

CVSS v2 Overall Score: 5.1      

Analysis

Impacted version

The Fast360 products include a vulnerable version of the bash command interpreter. At the time of writing, this vulnerability may be exploited only with a non-standard configuration of the DHCP client (“Cable modem interface” with the arkoon-config key “dhcp-client.get-dnsservers=yes”). The attacker needs to access the physical link connected to the cable modem interface.

Due to the central role of the bash interpreter, other non-identified attack vectors may be discovered. Consequently, preventive updates are available in Fast360 5.0/32 and 5.0/6 versions
  • Fast360 5.0/1 to 5.0/31
  • Fast360 6.0/1 to 6.0/4
  • Fast360 6.0/5 (Only available in Early Access Release)

Workaround solution

Solution

Concerning the DHCP client exploitation, the following workaround can be applied:

  • Change arkoon-config key value to “dhcp-client.get-dns-servers=no”

Fast360 5.0/32 and Fast360 6.0/6 versions include a fix for this problem. We recommend you to update your version as soon as possible.



Access vector Access complexity Authentication Confidentiality impact Integrity impact Availability impact
Local High None Complete Complete Complete
CVSS Base score: 6.2 CVSS Vector: (AV:L/AC:H/Au:N/C:C/I:C/A:C)
Exploitability Remediation Level Report Confidence
Unproven that exploit exists Workaround Unconfirmed
CVSS Temporal score: 4.5 CVSS Vector: (AV:L/AC:H/Au:N/C:C/I:C/A:C/E:U/RL:W/RC:UC)
Collateral Damage Potential Target Distribution
Low High [76-100%]
CVSS Environmental score: 5.1 CVSS Vector: (AV:L/AC:H/Au:N/C:C/I:C/A:C/E:U/RL:W/RC:UC/CDP:L/TD:H/CR:ND/IR:ND/AR:ND)