Software Engineering Institute

Entrust Authority Security Manager (EASM) is a public-key infrastructure (PKI) that includes a certificate authority (CA). EASM defines several privileged master users that have the ability to perform sensitive master user functions on the CA. Sensitive master user functions can be configured to require multiple authorizations by master users.

Changing the password of a master user is considered to be a sensitive operation that requires multiple authorizations. Under certain conditions, possibly involving the command line interface (CLI), the multiple authorization requirement is not enforced, allowing a single master user to change the password of another master user.

The following text was provided by Keith Sollers of Ernst & Young:

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Entrust Authority Security Manager Multiple Authorization Vulnerability

Ernst & Young announces the discovery of a vulnerability in Entrust
Authority Security Manager (EASM) for Solaris and Windows NT.

The Common Vulnerabilities and Exposures (CVE) project has assigned
the name CAN-2002-0712 to this issue. This is a candidate for inclusion
in the CVE list (http://cve.mitre.org), which standardizes names for
security problems.

Background:

EASM functions as a certificate authority within a public-key
infrastructure (PKI).  It issues certificates for entities and publishes
certificate status information to an associated repository.  Special
users, called master users, are responsible for maintenance of critical
processes that enable EASM to perform its core functions.  By default,
three master user IDs are created upon installation of EASM, master1,
master2, and master3.  These user IDs cannot be changed.

EASM can be configured to require multiple authorization for so-called
sensitive master user functions.  However, the master user function of
changing another master user's password is not a sensitive function.
Therefore, any one master user can circumvent the multiple authorization
requirement for any sensitive function by first changing another master
user's password to a known password, and then impersonating that other
master user during the multiple authorization process.

Systems Affected:

Solaris 7 and Windows NT 4.0 with EASM version 6.0 installed.  EASM
version 6.0 on other platforms, and previous versions of EASM on all
platforms, may also be affected, but were not tested.

Impact:

For systems that utilize the EASM multiple authorization feature for
master user sensitive functions, a single attacker would be successful
in performing unauthorized functions on the EASM, such as stopping critical
services (denial of service).

Recommendation:

For systems where the multiple authorization of master user sensitive
functions is desired, we recommend the introduction of mitigating logical
and/or physical controls that assure multiple master users are involved
during the multiple authorization process.

THE INFORMATION IN THIS VULNERABILITY ALERT IS PROVIDED BY ERNST & YOUNG LLP
"AS IS", "WHERE IS", WITH NO WARRANTY OF ANY KIND, AND ERNST & YOUNG LLP HEREBY
DISCLAIMS THE IMPLIED WARRANTIES OF NON-INFRINGEMENT, MERCHANTABILITY AND
FITNESS FOR A PARTICULAR PURPOSE.  ERNST & YOUNG LLP SHALL HAVE NO LIABILITY
FOR ANY DAMAGE, CLAIM OR LOSS RESULTING FROM YOUR USE OF THE INFORMATION
CONTAINED IN THIS VULNERABILITY ALERT.

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A single EASM master user could change the password of another master user, thereby gaining the ability perform sensitive operations that require multiple authorizations. This could allow a master user to stop EASM services, causing a denial of service.

Upgrade or Patch

This issue is resolved with mandatory upgrade 6.0.1 released on July 2, 2002.

Provide Physical Access Controls

Provide additional logical and/or physical access controls to enforce the multiple authorization requirement to change master users' passwords.