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Message-ID: <CAPu-DQoUvnUkXQ0F=kc4Mpa8=+3K_3X1dMf8v=+=MBPAGo0DoA@mail.gmail.com> Date: Fri, 26 Sep 2014 18:06:45 +0100 From: Gennady Kupava <gennady.kupava@...il.com> To: oss-security@...ts.openwall.com Subject: Fwd: CVE-2014-6271: remote code execution through bash The way how bash exports functions is really scary: 1. You can set both variable and export function with same name. $ f () { a; } $ export -f f $ export f=3 $ echo $f 3 $ ksh $ cat /proc/$$/environ|xargs -0 -n1|grep -w f f=3 f=() { a $ echo $f 3 SUS says storing two environment varianles with same name is undefined behavour: http://pubs.opengroup.org/onlinepubs/7908799/xbd/envvar.html 2. Bash partially hides environment variable holding function: $ f () { a; } $ export -f f $ echo $f [ nothing ] Both things above look like good grounds for hackers. Gennady
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