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posted by n1 on Thursday September 25 2014, @01:59AM   Printer-friendly
from the well,-that's-not-ideal dept.

Ars reports that a new bug has been found in GNU Bash allows remote attackers to execute arbitrary code by setting the process trailing strings after function definitions in the values of environment variables.

This bug is reported to be present in RHEL (ver 4 through 7), Fedora, CentOS (ver 5 through 7), Ubuntu (ver 10.04 LTS, 12.04 LTS, and 14.04 LTS), Debian, and even OS X Mavericks.

This bug is exploitable through Apache servers with mod_cgi and mod_cgid loaded, OpenSSH, malicious DHCP servers in a compromised wireless access point through dhclient, as well as the CUPS printing system.

The Ars also includes a simple single liner that will test your setup for the newly found discovery:

env x='() { :;}; echo vulnerable' bash -c "echo this is a test"

A vulnerable system will output the following:

vulnerable
 this is a test

While a patched or unaffected system outputs:

bash: warning: x: ignoring function definition attempt
bash: error importing function definition for `x'
this is a test

A patch is already out, so administrators are advised to update Bash.

Editor's Update: Security Engineer Tavis Ormandy has said "The bash patch seems incomplete to me, function parsing is still brittle".

$ env X='() { (a)=>\' sh -c "echo date"; cat echo

 
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  • (Score: 1) by b on Thursday September 25 2014, @02:10AM

    by b (2121) on Thursday September 25 2014, @02:10AM (#98027)

    Yes, unfortunately it does contain those vulnerabilities.

  • (Score: 0) by Anonymous Coward on Thursday September 25 2014, @02:15AM

    by Anonymous Coward on Thursday September 25 2014, @02:15AM (#98033)

    Shiiiiiiiiiiiiiiiiiiiit. This is not good at all!

  • (Score: 1) by b on Friday September 26 2014, @08:55AM

    by b (2121) on Friday September 26 2014, @08:55AM (#98518)

    And now Arch has patched this vulnerability too.