ubuntu-cve-2017-3737
Vulnerability from osv_ubuntu
Published
2017-12-07 00:00
Modified
2026-04-22 07:38
Summary
Details

OpenSSL 1.0.2 (starting from version 1.0.2b) introduced an "error state" mechanism. The intent was that if a fatal error occurred during a handshake then OpenSSL would move into the error state and would immediately fail if you attempted to continue the handshake. This works as designed for the explicit handshake functions (SSL_do_handshake(), SSL_accept() and SSL_connect()), however due to a bug it does not work correctly if SSL_read() or SSL_write() is called directly. In that scenario, if the handshake fails then a fatal error will be returned in the initial function call. If SSL_read()/SSL_write() is subsequently called by the application for the same SSL object then it will succeed and the data is passed without being decrypted/encrypted directly from the SSL/TLS record layer. In order to exploit this issue an application bug would have to be present that resulted in a call to SSL_read()/SSL_write() being issued after having already received a fatal error. OpenSSL version 1.0.2b-1.0.2m are affected. Fixed in OpenSSL 1.0.2n. OpenSSL 1.1.0 is not affected.

Severity
5.9 (Medium)
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
N/A (UNKNOWN)
medium
References
To clipboard 

{
  "affected": [
    {
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "libssl1.0.0",
            "binary_version": "1.0.2g-1ubuntu4.10"
          },
          {
            "binary_name": "openssl",
            "binary_version": "1.0.2g-1ubuntu4.10"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:16.04:LTS",
        "name": "openssl",
        "purl": "pkg:deb/ubuntu/openssl@1.0.2g-1ubuntu4.10?arch=source\u0026distro=xenial"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.0.2g-1ubuntu4.10"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.0.2d-0ubuntu1",
        "1.0.2d-0ubuntu2",
        "1.0.2e-1ubuntu1",
        "1.0.2f-2ubuntu1",
        "1.0.2g-1ubuntu2",
        "1.0.2g-1ubuntu3",
        "1.0.2g-1ubuntu4",
        "1.0.2g-1ubuntu4.1",
        "1.0.2g-1ubuntu4.2",
        "1.0.2g-1ubuntu4.4",
        "1.0.2g-1ubuntu4.5",
        "1.0.2g-1ubuntu4.6",
        "1.0.2g-1ubuntu4.8",
        "1.0.2g-1ubuntu4.9"
      ]
    }
  ],
  "aliases": [],
  "details": "OpenSSL 1.0.2 (starting from version 1.0.2b) introduced an \"error state\" mechanism. The intent was that if a fatal error occurred during a handshake then OpenSSL would move into the error state and would immediately fail if you attempted to continue the handshake. This works as designed for the explicit handshake functions (SSL_do_handshake(), SSL_accept() and SSL_connect()), however due to a bug it does not work correctly if SSL_read() or SSL_write() is called directly. In that scenario, if the handshake fails then a fatal error will be returned in the initial function call. If SSL_read()/SSL_write() is subsequently called by the application for the same SSL object then it will succeed and the data is passed without being decrypted/encrypted directly from the SSL/TLS record layer. In order to exploit this issue an application bug would have to be present that resulted in a call to SSL_read()/SSL_write() being issued after having already received a fatal error. OpenSSL version 1.0.2b-1.0.2m are affected. Fixed in OpenSSL 1.0.2n. OpenSSL 1.1.0 is not affected.",
  "id": "UBUNTU-CVE-2017-3737",
  "modified": "2026-04-22T07:38:09Z",
  "published": "2017-12-07T00:00:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2017-3737"
    },
    {
      "type": "REPORT",
      "url": "https://www.openssl.org/news/secadv/20171207.txt"
    },
    {
      "type": "ADVISORY",
      "url": "https://ubuntu.com/security/notices/USN-3512-1"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2017-3737"
    }
  ],
  "related": [
    "USN-3512-1"
  ],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N",
      "type": "CVSS_V3"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2017-3737"
  ]
}



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