Security Bulletin: Vulnerabilities in OpenSSL including Logjam affect IBM i

Summary

OpenSSL vulnerabilities were disclosed on June 11, 2015 by the OpenSSL Project. This includes Logjam Attack on TLS connections using the Diffie-Hellman (DH) key exchange protocol (CVE-2015-4000). OpenSSL is used by IBM i and IBM i has addressed the applicable CVEs.

Vulnerability Details

CVEID: CVE-2015-4000**
DESCRIPTION:** The TLS protocol could allow a remote attacker to obtain sensitive information, caused by the failure to properly convey a DHE_EXPORT ciphersuite choice. An attacker could exploit this vulnerability using man-in-the-middle techniques to force a downgrade to 512-bit export-grade cipher. Successful exploitation could allow an attacker to recover the session key as well as modify the contents of the traffic. This vulnerability is commonly referred to as “Logjam”.
CVSS Base Score: 4.3
CVSS Temporal Score: See https://exchange.xforce.ibmcloud.com/vulnerabilities/103294 for the current score
CVSS Environmental Score*: Undefined
CVSS Vector: (AV:N/AC:M/Au:N/C:P/I:N/A:N)

CVEID: CVE-2014-8176 DESCRIPTION: OpenSSL could allow a remote attacker to execute arbitrary code on the system, caused by an invalid free error when application data between the ChangeCipherSpec and Finished messages is received by the DTLS peer. An attacker could exploit this vulnerability to trigger a segmentation fault or possibly corrupt memory and execute arbitrary
CVSS Base Score: 6.5
CVSS Temporal Score: See https://exchange.xforce.ibmcloud.com/vulnerabilities/103782 for the current score
CVSS Environmental Score*: Undefined
CVSS Vector: (AV:N/AC:L/Au:S/C:P/I:P/A:P)

CVEID: CVE-2015-1788 DESCRIPTION: OpenSSL is vulnerable to a denial of service, caused by an error when processing an ECParameters structure over a specially crafted binary polynomial field. A remote attacker could exploit this vulnerability to cause the application to enter into an infinite loop.
CVSS Base Score: 5
CVSS Temporal Score: See https://exchange.xforce.ibmcloud.com/vulnerabilities/103778 for the current score
CVSS Environmental Score*: Undefined
CVSS Vector: (AV:N/AC:L/Au:N/C:N/I:N/A:P)

CVEID: CVE-2015-1789 DESCRIPTION: OpenSSL is vulnerable to a denial of service, caused by an out-of-bounds read in X509_cmp_time. An attacker could exploit this vulnerability using a specially crafted certificate or CRL to trigger a segmentation fault.
CVSS Base Score: 5
CVSS Temporal Score: See https://exchange.xforce.ibmcloud.com/vulnerabilities/103779 for the current score
CVSS Environmental Score*: Undefined
CVSS Vector: (AV:N/AC:L/Au:N/C:N/I:N/A:P)

CVEID: CVE-2015-1790 DESCRIPTION: OpenSSL is vulnerable to a denial of service, caused by the improper handling of missing inner EncryptedContent by the PKCS#7 parsing code. An attacker could exploit this vulnerability using specially crafted ASN.1-encoded PKCS#7 blobs with missing content to trigger a NULL pointer dereference.
CVSS Base Score: 5
CVSS Temporal Score: See https://exchange.xforce.ibmcloud.com/vulnerabilities/103780 for the current score
CVSS Environmental Score*: Undefined
CVSS Vector: (AV:N/AC:L/Au:N/C:N/I:N/A:P)

CVEID: CVE-2015-1791 DESCRIPTION: A double-free memory error in OpenSSL in the ssl3_get_new_session_ticket() function has an unknown impact. By returning a specially crafted NewSessionTicket message, an attacker could cause the client to reuse a previous ticket resulting in a race condition.
CVSS Base Score: 5
CVSS Temporal Score: See https://exchange.xforce.ibmcloud.com/vulnerabilities/103609 for the current score
CVSS Environmental Score*: Undefined
CVSS Vector: (AV:N/AC:L/Au:N/C:N/I:P/A:N)

CVEID: CVE-2015-1792 DESCRIPTION: OpenSSL is vulnerable to a denial of service, caused by an error when verifying a signedData message. An attacker could exploit this vulnerability using an unknown hash function OID to cause the application to enter into an infinite loop.
CVSS Base Score: 5
CVSS Temporal Score: See https://exchange.xforce.ibmcloud.com/vulnerabilities/103781 for the current score
CVSS Environmental Score*: Undefined
CVSS Vector: (AV:N/AC:L/Au:N/C:N/I:N/A:P)

CVEID: CVE-2015-1793 DESCRIPTION: OpenSSL could allow a remote attacker to bypass security restrictions, caused by an implementation error of the alternative certificate chain logic. An attacker could exploit this vulnerability to bypass the CA flag and other specific checks on untrusted certificates and issue an invalid certificate.
CVSS Base Score: 7.5
CVSS Temporal Score: See https://exchange.xforce.ibmcloud.com/vulnerabilities/104500 for the current score
CVSS Environmental Score*: Undefined
CVSS Vector: (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N)

Affected Products and Versions

Releases V5R3, V5R4, 6.1, 7.1 and 7.2 of IBM i are affected.

Remediation/Fixes

The issue can be fixed by applying a PTF to the IBM i Operating System.

Releases 6.1, 7.1 and 7.2 of IBM i are supported and will be fixed. Releases V5R3 and V5R4 are unsupported and will not be fixed.

The IBM i PTF numbers are:

Release 6.1 – SI57527 Release 7.1 – SI57473 Release 7.2 – SI57468

For CVE-2015-4000: As the length of the server key size are increased, the amount of CPU required for full TLS/SSL handshake can significantly increase. Please carefully test and assess the impact to your CPU requirements to ensure sufficient CPU resources, otherwise the system availability may be impacted.

For CVE-2015-4000: You should verify applying this configuration change does not cause any compatibility issues. If you change the default setting after applying the fix, you 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 Diffie-Hellman key-exchange protocol used in TLS and take appropriate mitigation and remediation actions.

_Important note: _IBM recommends that all users running unsupported versions of affected products upgrade to supported and fixed version of affected products.

Workarounds and Mitigations

None known