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IBM Lotus Domino remedy for BEAST Secure Socket Layer (SSL) 3.0 exploit recently published (CVE-2011-3389)

Technote (troubleshooting)


Problem

Researchers have published detailed information describing a new method to exploit a vulnerability caused by a known design error in the Secure Socket Layer (SSL) 3.0 and Transport Layer Security (TLS) 1.0 protocols when using a Cipher-Block Chaining (CBC) based cryptographic algorithm. This could allow a remote attacker to obtain sensitive information.

VULNERABILITY DETAILS

CVE ID: CVE-2011-3389

Description:
On 23 September 2011, researchers demonstrated a new attack called BEAST (short for Browser Exploit Against SSL/TLS) at a security conference in Argentina, as reported by various media outlets worldwide. The researchers claim they have found a way to gain access to sensitive information transmitting over the network that is protected using the Secure Socket Layer (SSL) 3.0 and Transport Layer Security (TLS) 1.0 protocols. By persuading a victim to visit a Web site, a remote attacker could exploit this vulnerability using man-in-the-middle techniques to decrypt HTTPS sessions and obtain sensitive information such as user authentication cookies that could be further leveraged to obtain sensitive information such as account and credit card numbers, user names, passwords, etc.


CVSS:
CVSS Base Score: 4.3
Temporal Score: See http://xforce.iss.net/xforce/xfdb/70069 for the current score
CVSS Environmental Score*: Undefined
CVSS Vector: (AV:N/AC:M/Au:N/C:P/I:N/A:N)


AFFECTED PLATFORMS:

IBM Lotus Domino (all releases) when configured to support SSL


REMEDIATION:
Customers can configure and use RC4 ciphers and remove the CBC ciphers on Domino to defeat this type of a threat. RC4 does not employ the weak form of Cipher-Block Chaining that lacks appropriate randomness. Domino SSL connections configured with AES encryption, which uses CBC, can alternatively use RC4. Note that RC4 is not compliant with NIST FIPS 140-2, and therefore may not be an option for those customers whose operations require strict FIPS 140-2 compliance.

To configure RC4 ciphers, Domino administrators should open the server document and select Ports-Internet Ports. For SSL Ciphers, select 'RC4 encryption with 128-bit key and MD5 MAC' and/or 'RC4 encryption with 128-bit key and SHA-1 MAC'


REFERENCES:

· Complete CVSS Guide
· On-line Calculator V2
· X-Force Vulnerability Database – SSL/TLS information disclosure
· CVE-2011-3389

*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 Flash.


Note: 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.


Document information

More support for: IBM Domino
Security

Software version: 8.0, 8.5

Operating system(s): AIX, IBM i, Linux, Solaris, Windows, z/OS

Reference #: 1568229

Modified date: 10 November 2011