Security Bulletin
Summary
IBM SONAS is shipped with Samba, for which a fix is available for security vulnerabilities.
Vulnerability Details
Samba is used in IBM SONAS to enable file management and authentication services for Microsoft Windows environments.
CVEID: CVE-2015-5252
DESCRIPTION: Samba could allow a remote attacker to launch a symlink attack, caused by the improper verification of symlinks by the smbd server. An attacker could exploit this vulnerability to gain access to files located outside of the exported share path.
CVSS Base Score: 5.3
CVSS Temporal Score: See https://exchange.xforce.ibmcloud.com/vulnerabilities/109137 for the current score
CVSS Environmental Score*: Undefined
CVSS Vector: (CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N)
CVEID: CVE-2015-5296
DESCRIPTION: Samba could allow a remote attacker to bypass security restrictions, caused by the failure to properly negotiate signing when establishing an encrypted connection. A remote attacker could exploit this vulnerability using man-in-the-middle techniques to perform downgrade attacks to connect via an unsigned, unencrypted connection.
CVSS Base Score: 4.3
CVSS Temporal Score: See https://exchange.xforce.ibmcloud.com/vulnerabilities/109138 for the current score
CVSS Environmental Score*: Undefined
CVSS Vector: (CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N)
CVEID: CVE-2015-5299
DESCRIPTION: Samba could allow a remote attacker to bypass security restrictions, caused by a missing access control check in the vfs_shadow_copy2 module. An attacker could exploit this vulnerability to view the current snapshots.
CVSS Base Score: 5.3
CVSS Temporal Score: See https://exchange.xforce.ibmcloud.com/vulnerabilities/109139 for the current score
CVSS Environmental Score*: Undefined
CVSS Vector: (CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N)
Affected Products and Versions
IBM SONAS
The product is affected when running a code releases 1.5.0.0 to 1.5.2.3
Remediation/Fixes
A fix for these issues is in version 1.5.2.4 of IBM SONAS. Customers running an affected version of SONAS should upgrade to 1.5.2.4 or a later version, so that the fix gets applied.
Please contact IBM support for assistance in upgrading your system.
Workarounds and Mitigations
Workaround(s) :
For CVE-2015-5252 : Ensure all exported share paths do not share base path names with other directories on the file system.
Please note, setting the smb.conf variable "follow symlinks = no" is not a workaround for this problem, as this only prohibits smbd from following a symlink at the end of a path.
For CVE-2015-5296 : When using the smbclient command, always add the argument "--signing=required" when using the "-e" or "--encrypt" argument.
Alternatively, set the variable "client signing = mandatory" in the [global] section of the smb.conf file on any client using encrypted connections.
To protect a Samba server exporting encrypted shares against a downgrade attack set the variable "smb encrypt = mandatory" in the smb.conf definition of the encrypted shares.
For CVE-2015-5299 : None.
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References
Change History
9 May 2016 : Original version published
*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.
Disclaimer
Review the IBM security bulletin disclaimer and definitions regarding your responsibilities for assessing potential impact of security vulnerabilities to your environment.
Internal Use Only
CQ S1061092 [PSIRT 4463] IBM product record 67329 for SONAS and 67330 for IFS - OpenSource Samba Vuln.
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Document Information
Modified date:
17 June 2018
UID
ssg1S1005693