Security Bulletin: Vulnerability in RC4 stream cipher affects Tivoli Storage Manager FastBack for Workstations (CVE-2015-2808)

Summary

The RC4 “Bar Mitzvah” Attack for SSL/TLS affects Tivoli Storage Manager FastBack for Workstations. The TSM FastBack for Workstations Central Administration Console (CAC) has a security vulnerability in the underlying IBM Webshpere and IBM WebSphere Liberty Server. Tivoli Storage Manager FastBack for Workstations (client) is affected when using WinHttp connections to a remote WebDav backup server. Since the cipher can be negotiated down to RC4 the CAC and client application are both affected.

Vulnerability Details

CVEID: CVE-2015-2808 DESCRIPTION: The RC4 algorithm, as used in the TLS protocol and SSL protocol, could allow a remote attacker to obtain sensitive information. An attacker could exploit this vulnerability to remotely expose account credentials without requiring an active man-in-the-middle session. Successful exploitation could allow an attacker to retrieve credit card data or other sensitive information. This vulnerability is commonly referred to as “Bar Mitzvah Attack”.
CVSS Base Score: 5
CVSS Temporal Score: See https://exchange.xforce.ibmcloud.com/vulnerabilities/101851 for the current score
CVSS Environmental Score*: Undefined
CVSS Vector: (AV:N/AC:L/Au:N/C:P/I:N/A:N)

Affected Products and Versions

The following versions of Tivoli Storage Manager for Workstations Central Administration Console are affected:
7.1.0.0 through 7.1.2.n
6.3.0.0 through 6.3.1.0

The following versions of Tivoli Storage Manger for Workstations (client) are affected:
7.1.0.0 through 7.1.2.n
6.3.0.0 through 6.3.1.12

Remediation/Fixes

Tivoli Storage Manager FastBack for WorkStations Central Administration Console

| First Fixing VRMF Level|Client
Platform|Link to Fix / Fix Availability Target
—|—|—|—
7.1| 7.1.3.0| Windows

x86

x64

| http://www.ibm.com/support/fixcentral/swg/quickorder?parent=ibm%7ETivoli&product=ibm/Tivoli/Tivoli+Storage+Manager+FastBack+for+Workstations&release=All&platform=Windows&function=fixId&fixids=7.1.3.0-TIV-FB4WKSTNS-CAC-x86_windows&includeSupersedes=0&source=fc

http://www.ibm.com/support/fixcentral/swg/quickorder?parent=ibm%7ETivoli&product=ibm/Tivoli/Tivoli+Storage+Manager+FastBack+for+Workstations&release=All&platform=Windows&function=fixId&fixids=7.1.3.0-TIV-FB4WKSTNS-CAC-x64_windows&includeSupersedes=0&source=fc
6.3| 6.3.1.1| Windows| [http://www.ibm.com/support/fixcentral/quickorder?product=ibm%2FTivoli%2FTivoli+Storage+Manager+FastBack+for+Workstations&fixids=6.3.1.1-TIV-FB4WKSTNS-CAC_windows&source=SAR](<http://www.ibm.com/support/fixcentral/quickorder?product=ibm%2FTivoli%2FTivoli+Storage+Manager+FastBack+for+Workstations&fixids=6.3.1.1-TIV-FB4WKSTNS-CAC_windows&source=SAR>)
Tivoli Storage Manager FastBack for WorkStations Client|First Fixing VRMF Level|Client
Platform|Link to Fix / Fix Availability Target
—|—|—|—
7.1| 7.1.3.0| Windows

x86

x64

| http://www.ibm.com/support/fixcentral/swg/quickorder?parent=ibm%7ETivoli&product=ibm/Tivoli/Tivoli+Storage+Manager+FastBack+for+Workstations&release=All&platform=Windows&function=fixId&fixids=7.1.3-TIV-FB4WKSTNS-x86_windows-FP0000&includeSupersedes=0&source=fc

http://www.ibm.com/support/fixcentral/swg/quickorder?parent=ibm%7ETivoli&product=ibm/Tivoli/Tivoli+Storage+Manager+FastBack+for+Workstations&release=All&platform=Windows&function=fixId&fixids=7.1.3-TIV-FB4WKSTNS-x64_windows-FP0000&includeSupersedes=0&source=fc
6.3| 6.3.1.13| Windows

x86

x64

| http://www.ibm.com/support/fixcentral/swg/quickorder?parent=ibm%7ETivoli&product=ibm/Tivoli/Tivoli+Storage+Manager+FastBack+for+Workstations&release=All&platform=Windows&function=fixId&fixids=6.3.1-TIV-FB4WKSTNS-x86_windows-FP0013&includeSupersedes=0&source=fc

http://www.ibm.com/support/fixcentral/swg/quickorder?parent=ibm%7ETivoli&product=ibm/Tivoli/Tivoli+Storage+Manager+FastBack+for+Workstations&release=All&platform=Windows&function=fixId&fixids=6.3.1-TIV-FB4WKSTNS-x64_windows-FP0013&includeSupersedes=0&source=fc

Workarounds and Mitigations

Tivoli Storage Manager FastBack for Workstations Central Administration Console

Version 6.3, 7.1.0 You will need to remove any of the ciphers that begin with SSL_* or TLS_* and contain RC4 in the name from your WebSphere Application Server SSL configuration.

You can view the administrative console page to change the settings, click Security > SSL certificate and key management. Under Configuration settings, click** Manage endpoint security configurations > {Inbound | Outbound} >****ssl_configuration. Under Related items, clickSSL configurations > . Click on {SSL_configuration_name }. UnderAdditional Properties**, clickQuality of protection (QoP) settings.
Perform a restart on the Tivoli Integrated Portal Service after saving the setting above.
Version 7.1.1, 7.1.2
1. Open the java.security file for editing. The file will be located in the Tivoli Storage Manager FastBack for Workstations Central Administration Console install directory\java\jre\lib\security.
2. Add the following line to the file: jdk.tls.disabledAlgorithms=RC4
3. In Control Panel -> Administrative Tools -> Service, stop and then restart the TSM FastBack for Workstations Central Administration Console service
Tivoli Storage Manager FastBack for Workstations (client):

Based on the Microsoft document: (<http://support.microsoft.com/en-us/kb/245030&gt;)
1. Open the registry and look under HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\Schannel\Ciphers\
2. For any RC4 cipher create the following registry key if it does not exist: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\Schannel\Ciphers\RC4 XXX/XXX (where examples are RC4 128/128, RC4 40/128, RC4 56/128, etc.)
3. Create a DWORD value named Enabled in the above mentioned key and set its value to 0. This is a computer wide setting and will impact any application that uses the Microsoft WinHttp functions.

A WebDav administrator should also be able to disable any RC4 cipher on the WebDav server which will eliminate the client vulnerability.
At this point the application will not allow RC4 ciphers.

You should verify applying this configuration change does not cause any compatibility issues. Not disabling the RC4 stream cipher will expose yourself to the attack described above. IBM recommends that you review your entire environment to identify other areas where you have enabled the RC4 stream cipher and take appropriate mitigation and remediation actions.