Apple Computer Mac OS X pppd Plugin Loading Privilege Escalation
iDefense Security Advisory 05.24.07
May 24, 2007
Apple Mac OS X pppd is a setuid root application that is used to
establish and configure connections for point to point links. It is
commonly used for configuring traditional dial-up modem and DSL
connections. More information can be found at the following URL.
Local exploitation of a privilege escalation vulnerability in Apple
Computer Inc.'s Mac OS X pppd could allow an attacker to gain root
The vulnerability exists due to insufficient access validation when
processing the "plugin" command line option. The application does not
properly verify that the requesting user has root privileges and allows
any user to load plug-ins.
When checking to see if the executing user has root privileges, a check
is made to see if the stdin file descriptor is owned by root. Passing
this check is trivial and allows the attacker to load arbitrary
plug-ins resulting in arbitrary code execution with root privileges.
Exploitation is trivial and grants root access.
This vulnerability cannot be triggered remotely; an attacker needs local
access to the victim's system in order to exploit this vulnerability.
pppd is installed by default.
iDefense has confirmed the existence of this vulnerability in version
10.4.8 of Mac OS X. Other versions may also be affected.
Remove the setuid bit from the pppd binary. This will prevent users
without root privileges from being able to properly use the program.
VI. VENDOR RESPONSE
Apple Inc has addressed this vulnerability in Apple Security Update
2007-005. More information can be found from Apple's Security Update
page or the Security Update 2007-005 advisory page at the respective
VII. CVE INFORMATION
The Common Vulnerabilities and Exposures (CVE) project has assigned the
name CVE-2007-0752 to this issue. This is a candidate for inclusion in
the CVE list (http://cve.mitre.org/), which standardizes names for
VIII. DISCLOSURE TIMELINE
01/08/2007 Initial vendor notification
01/09/2007 Initial vendor response
05/24/2007 Coordinated public disclosure
The discoverer of this vulnerability wishes to remain anonymous.
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X. LEGAL NOTICES
Copyright =A9 2007 iDefense, Inc.
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