useradd in shadow-utils before 4.0.3, and possibly other versions before 4.0.8, does not provide a required argument to the open function when creating a new user mailbox, which causes the mailbox to be created with unpredictable permissions and possibly allows attackers to read or modify the mailbox.

From Red Hat Security Advisory 2007:0431 :

An updated shadow-utils package that fixes a security issue and several bugs is now available.

This update has been rated as having low security impact by the Red Hat Security Response Team.

The shadow-utils package includes the necessary programs for converting UNIX password files to the shadow password format, as well as programs for managing user and group accounts.

A flaw was found in the useradd tool in shadow-utils. A new user's mailbox, when created, could have random permissions for a short period. This could allow a local attacker to read or modify the mailbox. (CVE-2006-1174)

This update also fixes the following bugs :

* shadow-utils debuginfo package was empty.

* chage.1 and chage -l gave incorrect information about sp_inact.

All users of shadow-utils are advised to upgrade to this updated package, which contains backported patches to resolve these issues.

From Red Hat Security Advisory 2007:0276 :

Updated shadow-utils packages that fix a security issue and various bugs are now available.

This update has been rated as having low security impact by the Red Hat Security Response Team.

The shadow-utils package includes the necessary programs for converting UNIX password files to the shadow password format, as well as programs for managing user and group accounts.

A flaw was found in the useradd tool in shadow-utils. A new user's mailbox, when created, could have random permissions for a short period. This could allow a local attacker to read or modify the mailbox. (CVE-2006-1174)

This update also fixes the following bugs :

* shadow-utils debuginfo package was empty.

* faillog was unusable on 64-bit systems. It checked every UID from 0 to the max UID, which was an excessively large number on 64-bit systems.

* typo bug in login.defs file

All users of shadow-utils are advised to upgrade to these updated packages, which contain backported patches to resolve these issues.

Updated shadow-utils packages that fix a security issue and various bugs are now available.

This update has been rated as having low security impact by the Red Hat Security Response Team.

The shadow-utils package includes the necessary programs for converting UNIX password files to the shadow password format, as well as programs for managing user and group accounts.

A flaw was found in the useradd tool in shadow-utils. A new user's mailbox, when created, could have random permissions for a short period. This could allow a local attacker to read or modify the mailbox. (CVE-2006-1174)

This update also fixes the following bugs :

* shadow-utils debuginfo package was empty.

* faillog was unusable on 64-bit systems. It checked every UID from 0 to the max UID, which was an excessively large number on 64-bit systems.

* typo bug in login.defs file

All users of shadow-utils are advised to upgrade to these updated packages, which contain backported patches to resolve these issues.

A flaw was found in the useradd tool in shadow-utils. A new user's mailbox, when created, could have random permissions for a short period. This could allow a local attacker to read or modify the mailbox. (CVE-2006-1174)

Problems addressed by these patches :

I    Arbitrary code execution and denial of service vulnerabilities

     This release fixes a security vulnerability that could allow a      guest operating system user with administrative privileges to cause      memory corruption in a host process, and thus potentially execute      arbitrary code on the host. (CVE-2007-4496)

     This release fixes a denial of service vulnerability that could      allow a guest operating system to cause a host process to become      unresponsive or exit unexpectedly. (CVE-2007-4497)

     Thanks to Rafal Wojtczvk of McAfee for identifying and reporting      these issues.

II   Hosted products DHCP security vulnerabilities addressed

     This release fixes several vulnerabilities in the DHCP server      that could enable a specially crafted packets to gain system-level      privileges. (CVE-2007-0061, CVE-2007-0062, CVE-2007-0063)

     Thanks to Neel Mehta and Ryan Smith of the IBM Internet Security      Systems X-Force for discovering and researching these      vulnerabilities.

III  Windows based hosted product vulnerability in      IntraProcessLogging.dll and vielib.dll.

     This release fixes a security vulnerability that could allow a      malicious remote user to exploit the library file      IntraProcessLogging.dll to overwrite files in a system.
     (CVE-2007-4059)

     This release fixes a security vulnerability that could allow a      malicious remote user to exploit the library file vielib.dll to      overwrite files in a system. (CVE-2007-4155)

     Thanks to the Goodfellas Security Research Team for discovering and      researching these vulnerabilities.

IV  Escalation of privileges on Windows hosted systems

     This release fixes a security vulnerability in which Workstation      was starting registered Windows services in an insecure manner.
     This vulnerability could allow a malicious user to escalate user      privileges.

     Thanks to Foundstone for discovering this vulnerability.

V    Potential denial of service using VMware Player

     This release fixes a problem that prevented VMware Player from      launching. This problem was accompanied by the error message VMware      Player unrecoverable error: (player) Exception 0xc0000005 (access      violation) has occurred.

VI   ESX Service Console updates

a.   Service console package Samba, has been updated to address the      following issues :

     Various bugs were found in NDR parsing, used to decode MS-RPC      requests in Samba. A remote attacker could have sent carefully      crafted requests causing a heap overflow, which may have led to the      ability to execute arbitrary code on the server. (CVE-2007-2446)

     Unescaped user input parameters were being passed as arguments to      /bin/sh. A remote, authenticated, user could have triggered this      flaw and executed arbitrary code on the server. Additionally, this      flaw could be triggered by a remote unauthenticated user if Samba      was configured to use the non-default username map script option.
     (CVE-2007-2447)

     Thanks to the Samba developers, TippingPoint, and iDefense for      identifying and reporting these issues.

     Note: These issues only affect the service console network, and are      not remote vulnerabilities for ESX Server hosts that have been set      up with the security best practices provided by VMware.
     http://www.vmware.com/resources/techresources/726

b.   Updated bind package for the service console fixes a flaw with the      way ISC BIND processed certain DNS query responses.

     ISC BIND (Berkeley Internet Name Domain) is an implementation of      the DNS (Domain Name System) protocols. Under some circumstances, a      malicious remote user could launch a Denial-of-Service attack on      ESX Server hosts that had enabled DNSSEC validation.
     (CVE-2007-0494)

     Note: These issues only affect the service console network, and are      not remote vulnerabilities for ESX Server hosts that have been set      up with the security best practices provided by VMware.
     http://www.vmware.com/resources/techresources/726

c.   This patch provides updated service console package krb5 update.

     The Common Vulnerabilities and Exposures project (cve.mitre.org)      assigned the names CVE-2007-2442, CVE-2007-2443, and CVE-2007-2798      to these security issues.

     Thanks to Wei Wang of McAfee Avert Labs discovered these      vulnerabilities.

     Note: The VMware service console does not provide the kadmind      binary, and is not affected by these issues, but a update has been      provided for completeness.

d.   Service console update for vixie-cron

     This patch provides an updated service console package vixie-cron.
     Cron is a standard UNIX daemon that runs specified programs at      scheduled times.

     A denial of service issue was found in the way vixie-cron verified      crontab file integrity. A local user with the ability to create a      hardlink to /etc/crontab could potentially prevent vixie-cron from      executing certain system cron jobs. (CVE-2007-1856)

     Thanks to Raphael Marichez for identifying this issue.

e.   Service console update for shadow-utils

     This patch provides an updated shadow-utils package.  A new      user's mailbox, when created, could have random permissions for a      short period. This could enable a local malicious user to      read or modify the mailbox. (CVE-2006-1174)

f.  Service console update for OpenLDAP

     This patch provides a updated OpenLDAP package. A flaw could      allow users with selfwrite access to modify the distinguished      name of any user, instead of being limited to modify only      their own distinguished name. (CVE-2006-4600)

g.   Service console update for PAM

     This patch provides an updated PAM package A vulnerability was      found that could allow console users with access to certain device      files to cause damage to recordable CD drives. Certain file      permissions have now been modified to disallow access.
     (CVE-2004-0813)

     A flaw was found with console device permissions. It was possible      for various console devices to retain ownership of the previoius      console user after logging out, which could result in leakage of      information to an unauthorized user. (CVE-2007-1716)

h.   Service console update for GCC

     This patch provides security fixes for the service console GNU      Compiler Collection (GCC) packages that include C, C++, Java,      Fortran 77, Objective C, and Ada 95 GNU compilers and related      support libraries.

     A flaw was found in the fastjar utility that could potentially      allow a malicious user to create a JAR file which, if unpacked      using fastjar, could write to any file that an authorized user had      write access to. (CVE-2006-3619)

     Thanks to J&uuml;rgen Weigert for identifying this issue.

i.   Service Console update for GDB

     This patch provides a security fix for the service console GNU      debugger (GDB).  Various vulnerabilities were found in GDB. These      vulnerabilities may allow a malicious user to deceive a user into      loading debugging information into GDB, enabling the execution of      arbitrary code with the privileges of the user. (CVE-2006-4146)

An updated shadow-utils package that fixes a security issue and several bugs is now available.

This update has been rated as having low security impact by the Red Hat Security Response Team.

The shadow-utils package includes the necessary programs for converting UNIX password files to the shadow password format, as well as programs for managing user and group accounts.

A flaw was found in the useradd tool in shadow-utils. A new user's mailbox, when created, could have random permissions for a short period. This could allow a local attacker to read or modify the mailbox. (CVE-2006-1174)

This update also fixes the following bugs :

* shadow-utils debuginfo package was empty.

* chage.1 and chage -l gave incorrect information about sp_inact.

All users of shadow-utils are advised to upgrade to this updated package, which contains backported patches to resolve these issues.

The remote Redhat Enterprise Linux 4 host has a package installed that is affected by a vulnerability as referenced in the RHSA-2007:0276 advisory.

    The shadow-utils package includes the necessary programs for converting     UNIX password files to the shadow password format, as well as programs for     managing user and group accounts.

    A flaw was found in the useradd tool in shadow-utils. A new user's     mailbox, when created, could have random permissions for a short period.
    This could allow a local attacker to read or modify the mailbox.
    (CVE-2006-1174)

    This update also fixes the following bugs:

    * shadow-utils debuginfo package was empty.

    * faillog was unusable on 64-bit systems. It checked every UID from 0 to     the max UID, which was an excessively large number on 64-bit systems.

    * typo bug in login.defs file

    All users of shadow-utils are advised to upgrade to these updated packages,     which contain backported patches to resolve these issues.

Tenable has extracted the preceding description block directly from the Red Hat Enterprise Linux security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The remote host is affected by the vulnerability described in GLSA-200606-02 (shadow: Privilege escalation)

    When the mailbox is created in useradd, the 'open()' function does     not receive the three arguments it expects while O_CREAT is present,     which leads to random permissions on the created file, before fchmod()     is executed.
  Impact :

    Depending on the random permissions given to the mailbox file     which is at this time owned by root, a local user may be able to open     this file for reading or writing, or even executing it, maybe as the     root user.
  Workaround :

    There is no known workaround at this time.

ID	Name	Product	Family	Severity
67515	Oracle Linux 3 : shadow-utils (ELSA-2007-0431)	Nessus	Oracle Linux Local Security Checks	low
67482	Oracle Linux 4 : shadow-utils (ELSA-2007-0276)	Nessus	Oracle Linux Local Security Checks	low
67048	CentOS 4 : shadow-utils (CESA-2007:0276)	Nessus	CentOS Local Security Checks	low
60203	Scientific Linux Security Update : shadow-utils on SL3.x i386/x86_64	Nessus	Scientific Linux Local Security Checks	low
60170	Scientific Linux Security Update : shadow-utils on SL4.x i386/x86_64	Nessus	Scientific Linux Local Security Checks	low
40370	VMSA-2007-0006 : Critical security updates for all supported versions of VMware ESX Server, VMware Server, VMware Workstation, VMware ACE, and VMware Player	Nessus	VMware ESX Local Security Checks	critical
25497	CentOS 3 : shadow-utils (CESA-2007:0431)	Nessus	CentOS Local Security Checks	low
25478	RHEL 3 : shadow-utils (RHSA-2007:0431)	Nessus	Red Hat Local Security Checks	low
25144	RHEL 4 : shadow-utils (RHSA-2007:0276)	Nessus	Red Hat Local Security Checks	critical
21664	GLSA-200606-02 : shadow: Privilege escalation	Nessus	Gentoo Local Security Checks	low

Detections

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CVE-2006-1174

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