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Security updates for all active release lines, September 2016

September 23rd, 2016

The Node.js project has scheduled updates for all of its active release lines to patch a number of security flaws. These flaws include some of those announced by the OpenSSL project as well as a number of Node.js-specific issues. We do not consider any of these updates to be critical. However, it is strongly recommended that all production instances of Node.js be upgraded when the releases are made available. We intend to make releases available on or soon after the evening of Tuesday, the 27th of September, 2016, UTC (midday US time). We consider some of the patches in these releases to be API breaking changes which would normally warrant an increase in the major-version number of Node.js. However, in accordance with our security procedures, we will be delivering these changes in minor-version increases (the y in x.y.z) where appropriate, and patch-version increases in v0.10 an v0.12 releases. These are the expected version numbers for the releases:
  • Node.js v6.7.0 (Current)
  • Node.js v4.6.0 (LTS "Argon")
  • Node.js v0.12.16 (Maintenance)
  • Node.js v0.10.47 (Maintenance)
Additional notes:
  • As per our LTS schedule, support for Node.js v0.10 will cease in October. Therefore, this may be the final release of Node.js v0.10. If you are still using v0.10 in production, it is essential that you plan for a migration to v4 (LTS "Argon") or v6 (LTS to be announced in October) as soon as possible.
  • In accordance with our security release procedures, we will be limiting changes included in the LTS and Maintenance lines (v4, v0.12, and v0.10) for these updates to only security-related and other critical fixes that provide for maximum stability for users.

Node.js-specific security flaws

Included in these releases will be a number of fixes unrelated to the recent OpenSSL releases. These include:
  • A high-severity flaw relating to the processing of TLS certificates, impacting all versions of Node.js
  • A low-severity native code injection vulnerability on Windows, impacting all versions of Node.js
  • A low-severity HTTP validation error, impacting all versions of Node.js
Full disclosure of fixed vulnerabilities will be provided after all releases are made available for download.

September OpenSSL Releases

The OpenSSL project has announced the general availability of versions 1.0.2i (to be included in Node.js v4 and above) and 1.0.1u (to be included in Node.js v0.10 and v0.12). Our crypto team (Shigeki Ohtsu, Fedor Indutny, and Ben Noordhuis) have performed an analysis of the defects addressed in the OpenSSL releases to determine their impact on Node.js. The results of this analysis are included below.

CVE-2016-6304: OCSP Status Request extension unbounded memory growth

A malicious client can exhaust a server's memory, resulting in a denial of service (DoS) by sending very large OCSP Status Request extensions in a single session. This flaw is labelled high severity due to the ease of use for a DoS attack and Node.js servers using TLS are vulnerable. Assessment: All versions of Node.js are affected by this vulnerability.

CVE-2016-6305: SSL_peek() hang on empty record

OpenSSL 1.1.0 SSL/TLS will hang during a call to SSL_peek() if the peer sends an empty record. Node.js is not yet dependent on OpenSSL 1.1.0 so it is not impacted by this flaw. Assessment: All versions of Node.js are believed to be unaffected by this vulnerability.

CVE-2016-2183: SWEET32 Mitigation

SWEET32 is a new attack on older block cipher algorithms that use a block size of 64 bits. As mitigation, OpenSSL has moved DES-based ciphers from the HIGH to MEDIUM group. As Node.js includes HIGH, but not MEDIUM, in its default suite, affected ciphers are no longer included unless the default suite is not used. Node's default TLS cipher suite can be found in the API documentation. Assessment: All versions of Node.js are affected by this vulnerability.

CVE-2016-6303: OOB write in MDC2_Update()

An overflow can occur in MDC2_Update() under certain circumstances resulting in an out of bounds (OOB) error. This attack is impractical on most platforms due to the size of data required to trigger the OOB error. Node.js is impacted by this flaw but due to the impracticalities of exploiting it and the very low usage of of MDC-2, it is very low severity for Node.js users. Assessment: All versions of Node.js are affected by this vulnerability.

CVE-2016-6302: Malformed SHA512 ticket DoS

If a server uses SHA512 for TLS session ticket HMAC, it is vulnerable to a denial of service (DoS) attack via crash upon receiving a malformed ticket. Node.js does not use SHA512 for session tickets and is therefore not impacted by this flaw. Assessment: All versions of Node.js are believed to be unaffected by this vulnerability.

CVE-2016-2182: OOB write in BN_bn2dec()

An out of bounds (OOB) write can occur in BN_bn2dec() if an application uses this function with an overly large BIGNUM. TLS is not affected because record limits will reject an oversized certificate before it is parsed. Assessment: All versions of Node.js are believed to be unaffected by this vulnerability.

CVE-2016-2180: OOB read in TS_OBJ_print_bio()

An out of bounds (OOB) read can occur when large OIDs are presented via TS_OBJ_print_bio(). Node.js does not make use of the Time Stamp Authority functionality in OpenSSL and is therefore believed to be unaffected by this flaw. Assessment: All versions of Node.js are believed to be unaffected by this vulnerability.

CVE-2016-2177: Pointer arithmetic undefined behaviour

This programming flaw is described in the post at https://www.openssl.org/blog/blog/2016/06/27/undefined-pointer-arithmetic/. It is unlikely that Node.js users are directly impacted by this. Assessment: All versions of Node.js are believed to be unaffected by this vulnerability.

CVE-2016-2178: Constant time flag not preserved in DSA signing

A flaw in the OpenSSL DSA implementation means that a non-constant time codepath is followed for certain operations. This has been demonstrated through a cache-timing attack to be sufficient for an attacker to recover the private DSA key. This is very low severity for Node.js users due to the difficulty in taking advantage of this attack and because DSA is very rarely used. Assessment: All versions of Node.js are affected by this vulnerability.

CVE-2016-2179: DTLS buffered message DoS

In a DTLS connection where handshake messages are delivered out-of-order, those messages that OpenSSL is not yet ready to process will be buffered for later use. This can be exploited to cause a denial of service (DoS) via memory exhaustion. As Node.js does not support DTLS, users are not impacted by this flaw. Assessment: All versions of Node.js are believed to be unaffected by this vulnerability.

CVE-2016-2179: DTLS replay protection DoS

A flaw in the DTLS replay attack protection mechanism that would allow an attacker to force a server to drop legitimate packets for a DTLS connection, resulting in a denial of service (DoS) for that connection. As Node.js does not support DTLS, users are not impacted by this flaw. Assessment: All versions of Node.js are believed to be unaffected by this vulnerability.

CVE-2016-6306: Certificate message OOB reads

Some missing message length checks can result in out of bounds (OOB) reads of up to 2 bytes beyond an allocated buffer. There is a theoretical denial of service (DoS) risk. This only impacts a client or a server which enables client authentication. Node.js is impacted by this low severity flaw. Assessment: All versions of Node.js are affected by this vulnerability.

CVE-2016-6307: Excessive allocation of memory in tls_get_message_header()

Excessive allocation of memory in OpenSSL 1.1.0 can be achieved by manipulating the length component of a TLS header. Node.js is not yet dependent on OpenSSL 1.1.0 so it is not impacted by this flaw. Assessment: All versions of Node.js are believed to be unaffected by this vulnerability.

CVE-2016-6308: Excessive allocation of memory in dtls1_preprocess_fragment()

A flaw that is similar to CVE-2016-6307 but impacting DTLS. Node.js is not yet dependent on OpenSSL 1.1.0, nor does it implement DTLS, so it is not impacted by this flaw. Assessment: All versions of Node.js are believed to be unaffected by this vulnerability.

Contact and future updates

Please monitor the nodejs-sec Google Group for updates: https://groups.google.com/forum/#!forum/nodejs-sec or the Node.js website for release announcements: https://nodejs.org/en/blog/ The current Node.js security policy can be found at https://nodejs.org/en/security/. Please contact security@nodejs.org if you wish to report a vulnerability in Node.js. Subscribe to the low-volume announcement-only nodejs-sec mailing list at https://groups.google.com/forum/#!forum/nodejs-sec to stay up to date on security vulnerabilities and security-related releases of Node.js and the projects maintained in the nodejs GitHub organisation.