Re: Multiple OS kernel insecure handling of stdio file descriptor

[Peter Jeremy <peter.jeremy () alcatel-lucent com au>]

On 2007-Jan-18 22:21:52 +0800, XFOCUS Security Team <security () xfocus org> wrote:
> The affected OSes allows local users to write to or read from restricted
> files by closing the file descriptors 0 (standard input), 1 (standard
> output), or 2 (standard error), which may then be reused by a called
> setuid process that intended to perform I/O on normal files. the attack
> which exploit this vulnerability possibly get root right.

This vulnerability has been known for years.  OpenBSD implemented a
kernel check to block this attack in 1998.  FreeBSD and NetBSD have
similar kernel checks and I believe glibc also has checks to block
this.  It is disturbing that none of the commercial OS vendors appear
to have bothered to protect against this.

-- 
Peter Jeremy

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