The vulnerable system is not bound to the network stack and the attacker’s path is via read/write/execute capabilities. Either: the attacker exploits the vulnerability by accessing the target system locally (e.g., keyboard, console), or through terminal emulation (e.g., SSH); or the attacker relies on User Interaction by another person to perform actions required to exploit the vulnerability (e.g., using social engineering techniques to trick a legitimate user into opening a malicious document).
Attack Complexity
Low
AC
The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system.
Privileges Required
Low
PR
The attacker requires privileges that provide basic capabilities that are typically limited to settings and resources owned by a single low-privileged user. Alternatively, an attacker with Low privileges has the ability to access only non-sensitive resources.
User Interaction
None
UI
The vulnerable system can be exploited without interaction from any human user, other than the attacker. Examples include: a remote attacker is able to send packets to a target system a locally authenticated attacker executes code to elevate privileges
Scope
Unchanged
S
An exploited vulnerability can only affect resources managed by the same security authority. In the case of a vulnerability in a virtualized environment, an exploited vulnerability in one guest instance would not affect neighboring guest instances.
Confidentiality
High
C
There is total information disclosure, resulting in all data on the system being revealed to the attacker, or there is a possibility of the attacker gaining control over confidential data.
Integrity
High
I
There is a total compromise of system integrity. There is a complete loss of system protection, resulting in the attacker being able to modify any file on the target system.
Availability
High
A
There is a total shutdown of the affected resource. The attacker can deny access to the system or data, potentially causing significant loss to the organization.
Multiple Vendor XMail 'sendmail' Recipient Buffer Overflow Vulnerability
iDEFENSE Security Advisory 10.13.05
www.idefense.com/application/poi/display?id=321&type=vulnerabilities
October 13, 2005
I. BACKGROUND
XMail is an Internet and intranet mail server. XMail sources compile
under GNU/Linux, FreeBSD, OpenBSD, NetBSD, OSX, Solaris and NT/2K/XP.
More information can be found at the vendor website:
http://www.xmailserver.org/
II. DESCRIPTION
Local exploitation of a buffer overflow vulnerability in XMail, as
distributed with multiple vendors' operating systems, allows local
attackers to execute arbitrary code with elevated privileges.
The vulnerability exists because of insufficent bounds checking on
user-supplied data. Specifically, the AddressFromAtPtr function fails to
check bounds on arguments passed from other functions, and as a result
an exploitable stack overflow condition occurs when specifying the "-t"
command line option. The "-t" command line option allows users to
specify the recipient value in the text of the message on a line
beginning with "To:". XMail passes the user-supplied value without
bounds checking to AdressFromAtPtr and attempts to store the hostname
portion of the e-mail address in a 256-byte buffer. Crafted e-mail
addresses can overflow the buffer and overwrite stack process control
data, resulting in local code execution with elevated privileges.
III. ANALYSIS
Successful exploitation will result in code execution with elevated
privileges. XMail is distributed in RPM, DEB and source format. The RPM
distribution installs the sendmail binary with setuid root privileges.
Exploitation of XMail installed from RPM will yield root. Other
distribution formats install the sendmail binary as setgid mail.
Exploitation resulting in group mail privileges will allow an attacker
to read all unencrypted mail stored locally in the system mail folders.
IV. DETECTION
iDEFENSE Labs has confirmed the existence of this vulnerability in XMail
1.21.
V. WORKAROUND
As a workaround solution, local mail delivery can be restricted and a
standard mail user-agent may be used to talk to the XMail SMTP server.
VI. VENDOR RESPONSE
The vendor has released XMail 1.22 to address this issue which is
available for download at:
http://www.xmailserver.org/
VII. CVE INFORMATION
The Common Vulnerabilities and Exposures (CVE) project has assigned the
name CAN-2005-2943 to this issue. This is a candidate for inclusion in
the CVE list (http://cve.mitre.org), which standardizes names for
security problems.
VIII. DISCLOSURE TIMELINE
10/12/2005 Initial vendor notification
10/12/2005 Initial vendor response
10/13/2005 Coordinated public disclosure
IX. CREDIT
The discoverer of this vulnerability wishes to remain anonymous.
Get paid for vulnerability research
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http://labs.idefense.com
X. LEGAL NOTICES
Copyright (c) 2005 iDEFENSE, Inc.
Permission is granted for the redistribution of this alert
electronically. It may not be edited in any way without the express
written consent of iDEFENSE. If you wish to reprint the whole or any
part of this alert in any other medium other than electronically, please
email customerservice (at) idefense (dot) com [email concealed] for permission.
Disclaimer: The information in the advisory is believed to be accurate
at the time of publishing based on currently available information. Use
of the information constitutes acceptance for use in an AS IS condition.
There are no warranties with regard to this information. Neither the
author nor the publisher accepts any liability for any direct, indirect,
or consequential loss or damage arising from use of, or reliance on,
this information.