Date: 11 March 2016
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AUSCERT External Security Bulletin Redistribution
Security Bulletin: Vulnerability in Install of Informix
Dynamic Server on Windows (CVE-2016-0226)
11 March 2016
AusCERT Security Bulletin Summary
Product: IBM Informix Servers
Operating System: Windows
Impact/Access: Execute Arbitrary Code/Commands -- Existing Account
CVE Names: CVE-2016-0226
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Security Bulletin: Vulnerability in Install of Informix Dynamic Server on
More support for:
IBM Informix Dynamic Server could allow a local user to modify the
nsrexecd.exe file in the ISM directory. A local user can replace the
nsrexecd.exe service binary with a file of his choice, and that binary will be
executed as a service in the context of system.
Installation creates an ISM directory under the root of C: . The permissions
for files in this directory get inherited for directories and files created
under ISM. The resulting weak ACL is inherited from the default ACL on the ISM
directory. Because of this vulnerability, any authenticated user can replace
the service binary with a file of his choice, and that binary will be executed
as a service in the context of system.
CVEID: CVEID: CVE-2016-0226
DESCRIPTION: IBM Informix Dynamic Server Install could leave the ACL of the
C:\ISM directory vulnerable such that a local user can replace the
nsrexecd.exe service binary with a file of his choice.
CVSS Base Score: 8.4
CVSS Temporal Score: See
https://exchange.xforce.ibmcloud.com/vulnerabilities/110087 for the current
CVSS Environmental Score*: Undefined
CVSS Vector: (CVSS:3.0/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H)
Affected Products and Versions
IBM Informix Dynamic Server 11.70.xCn on Windows Platforms
The fix is to change the ACL on the C:\ISM directory so that unauthorized
users cant change the content of this directory.
There is a script available on FixCentral that will make this change.
Workarounds and Mitigations
System administrators can manually change the ACL of the C:\ISM directory
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Complete CVSS v3 Guide
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IBM Secure Engineering Web Portal
IBM Product Security Incident Response Blog
The vulnerability was reported to IBM by Steven Seeley of Source Incite
working with HP's Zero Day Initiative
*The CVSS Environment Score is customer environment specific and will
ultimately impact the Overall CVSS Score. Customers can evaluate the impact of
this vulnerability in their environments by accessing the links in the
Reference section of this Security Bulletin.
According to the Forum of Incident Response and Security Teams (FIRST), the
Common Vulnerability Scoring System (CVSS) is an "industry open standard
designed to convey vulnerability severity and help to determine urgency and
priority of response." IBM PROVIDES THE CVSS SCORES "AS IS" WITHOUT WARRANTY
OF ANY KIND, INCLUDING THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
FOR A PARTICULAR PURPOSE. CUSTOMERS ARE RESPONSIBLE FOR ASSESSING THE IMPACT
OF ANY ACTUAL OR POTENTIAL SECURITY VULNERABILITY.
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