USN-4559-1 (UBUNTU-CVE-2020-1472)

Vulnerability from osv_ubuntu – Published: 2020-09-30 13:44 – Updated: 2026-04-22 07:36 – Source website
VLAI
Summary
samba update
Details

Tom Tervoort discovered that the Netlogon protocol implemented by Samba incorrectly handled the authentication scheme. A remote attacker could use this issue to forge an authentication token and steal the credentials of the domain admin.

While a previous security update fixed the issue by changing the "server schannel" setting to default to "yes", instead of "auto", which forced a secure netlogon channel, this update provides additional improvements.

For compatibility reasons with older devices, Samba now allows specifying an insecure netlogon configuration per machine. See the following link for examples: https://www.samba.org/samba/security/CVE-2020-1472.html

In addition, this update adds additional server checks for the protocol attack in the client-specified challenge to provide some protection when 'server schannel = no/auto' and avoid the false-positive results when running the proof-of-concept exploit.

References
To clipboard 

{
  "affected": [
    {
      "database_specific": {
        "cves_map": {
          "cves": [
            {
              "id": "CVE-2020-1472",
              "severity": [
                {
                  "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H",
                  "type": "CVSS_V3"
                },
                {
                  "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N",
                  "type": "CVSS_V3"
                },
                {
                  "score": "medium",
                  "type": "Ubuntu"
                }
              ]
            }
          ],
          "ecosystem": "Ubuntu:16.04:LTS"
        }
      },
      "ecosystem_specific": {
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      },
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        "2:4.3.11+dfsg-0ubuntu0.16.04.7",
        "2:4.3.11+dfsg-0ubuntu0.16.04.8",
        "2:4.3.11+dfsg-0ubuntu0.16.04.9",
        "2:4.3.11+dfsg-0ubuntu0.16.04.10",
        "2:4.3.11+dfsg-0ubuntu0.16.04.11",
        "2:4.3.11+dfsg-0ubuntu0.16.04.12",
        "2:4.3.11+dfsg-0ubuntu0.16.04.13",
        "2:4.3.11+dfsg-0ubuntu0.16.04.15",
        "2:4.3.11+dfsg-0ubuntu0.16.04.16",
        "2:4.3.11+dfsg-0ubuntu0.16.04.17",
        "2:4.3.11+dfsg-0ubuntu0.16.04.18",
        "2:4.3.11+dfsg-0ubuntu0.16.04.19",
        "2:4.3.11+dfsg-0ubuntu0.16.04.20",
        "2:4.3.11+dfsg-0ubuntu0.16.04.21",
        "2:4.3.11+dfsg-0ubuntu0.16.04.23",
        "2:4.3.11+dfsg-0ubuntu0.16.04.24",
        "2:4.3.11+dfsg-0ubuntu0.16.04.25",
        "2:4.3.11+dfsg-0ubuntu0.16.04.26",
        "2:4.3.11+dfsg-0ubuntu0.16.04.27",
        "2:4.3.11+dfsg-0ubuntu0.16.04.28",
        "2:4.3.11+dfsg-0ubuntu0.16.04.29",
        "2:4.3.11+dfsg-0ubuntu0.16.04.30"
      ]
    },
    {
      "database_specific": {
        "cves_map": {
          "cves": [
            {
              "id": "CVE-2020-1472",
              "severity": [
                {
                  "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H",
                  "type": "CVSS_V3"
                },
                {
                  "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N",
                  "type": "CVSS_V3"
                },
                {
                  "score": "medium",
                  "type": "Ubuntu"
                }
              ]
            }
          ],
          "ecosystem": "Ubuntu:18.04:LTS"
        }
      },
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "ctdb",
            "binary_version": "2:4.7.6+dfsg~ubuntu-0ubuntu2.20"
          },
          {
            "binary_name": "libnss-winbind",
            "binary_version": "2:4.7.6+dfsg~ubuntu-0ubuntu2.20"
          },
          {
            "binary_name": "libpam-winbind",
            "binary_version": "2:4.7.6+dfsg~ubuntu-0ubuntu2.20"
          },
          {
            "binary_name": "libparse-pidl-perl",
            "binary_version": "2:4.7.6+dfsg~ubuntu-0ubuntu2.20"
          },
          {
            "binary_name": "libsmbclient",
            "binary_version": "2:4.7.6+dfsg~ubuntu-0ubuntu2.20"
          },
          {
            "binary_name": "libwbclient0",
            "binary_version": "2:4.7.6+dfsg~ubuntu-0ubuntu2.20"
          },
          {
            "binary_name": "python-samba",
            "binary_version": "2:4.7.6+dfsg~ubuntu-0ubuntu2.20"
          },
          {
            "binary_name": "registry-tools",
            "binary_version": "2:4.7.6+dfsg~ubuntu-0ubuntu2.20"
          },
          {
            "binary_name": "samba",
            "binary_version": "2:4.7.6+dfsg~ubuntu-0ubuntu2.20"
          },
          {
            "binary_name": "samba-common",
            "binary_version": "2:4.7.6+dfsg~ubuntu-0ubuntu2.20"
          },
          {
            "binary_name": "samba-common-bin",
            "binary_version": "2:4.7.6+dfsg~ubuntu-0ubuntu2.20"
          },
          {
            "binary_name": "samba-dsdb-modules",
            "binary_version": "2:4.7.6+dfsg~ubuntu-0ubuntu2.20"
          },
          {
            "binary_name": "samba-libs",
            "binary_version": "2:4.7.6+dfsg~ubuntu-0ubuntu2.20"
          },
          {
            "binary_name": "samba-testsuite",
            "binary_version": "2:4.7.6+dfsg~ubuntu-0ubuntu2.20"
          },
          {
            "binary_name": "samba-vfs-modules",
            "binary_version": "2:4.7.6+dfsg~ubuntu-0ubuntu2.20"
          },
          {
            "binary_name": "smbclient",
            "binary_version": "2:4.7.6+dfsg~ubuntu-0ubuntu2.20"
          },
          {
            "binary_name": "winbind",
            "binary_version": "2:4.7.6+dfsg~ubuntu-0ubuntu2.20"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:18.04:LTS",
        "name": "samba",
        "purl": "pkg:deb/ubuntu/samba@2:4.7.6+dfsg~ubuntu-0ubuntu2.20?arch=source\u0026distro=bionic"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2:4.7.6+dfsg~ubuntu-0ubuntu2.20"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2:4.6.7+dfsg-1ubuntu3",
        "2:4.7.1+dfsg-1ubuntu1",
        "2:4.7.3+dfsg-1ubuntu1",
        "2:4.7.4+dfsg-1ubuntu1",
        "2:4.7.6+dfsg~ubuntu-0ubuntu1",
        "2:4.7.6+dfsg~ubuntu-0ubuntu2",
        "2:4.7.6+dfsg~ubuntu-0ubuntu2.2",
        "2:4.7.6+dfsg~ubuntu-0ubuntu2.4",
        "2:4.7.6+dfsg~ubuntu-0ubuntu2.5",
        "2:4.7.6+dfsg~ubuntu-0ubuntu2.6",
        "2:4.7.6+dfsg~ubuntu-0ubuntu2.7",
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        "2:4.7.6+dfsg~ubuntu-0ubuntu2.19"
      ]
    },
    {
      "database_specific": {
        "cves_map": {
          "cves": [
            {
              "id": "CVE-2020-1472",
              "severity": [
                {
                  "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H",
                  "type": "CVSS_V3"
                },
                {
                  "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N",
                  "type": "CVSS_V3"
                },
                {
                  "score": "medium",
                  "type": "Ubuntu"
                }
              ]
            }
          ],
          "ecosystem": "Ubuntu:20.04:LTS"
        }
      },
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "ctdb",
            "binary_version": "2:4.11.6+dfsg-0ubuntu1.5"
          },
          {
            "binary_name": "libnss-winbind",
            "binary_version": "2:4.11.6+dfsg-0ubuntu1.5"
          },
          {
            "binary_name": "libpam-winbind",
            "binary_version": "2:4.11.6+dfsg-0ubuntu1.5"
          },
          {
            "binary_name": "libsmbclient",
            "binary_version": "2:4.11.6+dfsg-0ubuntu1.5"
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          {
            "binary_name": "libwbclient0",
            "binary_version": "2:4.11.6+dfsg-0ubuntu1.5"
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            "binary_version": "2:4.11.6+dfsg-0ubuntu1.5"
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          {
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            "binary_version": "2:4.11.6+dfsg-0ubuntu1.5"
          },
          {
            "binary_name": "samba",
            "binary_version": "2:4.11.6+dfsg-0ubuntu1.5"
          },
          {
            "binary_name": "samba-common",
            "binary_version": "2:4.11.6+dfsg-0ubuntu1.5"
          },
          {
            "binary_name": "samba-common-bin",
            "binary_version": "2:4.11.6+dfsg-0ubuntu1.5"
          },
          {
            "binary_name": "samba-dsdb-modules",
            "binary_version": "2:4.11.6+dfsg-0ubuntu1.5"
          },
          {
            "binary_name": "samba-libs",
            "binary_version": "2:4.11.6+dfsg-0ubuntu1.5"
          },
          {
            "binary_name": "samba-testsuite",
            "binary_version": "2:4.11.6+dfsg-0ubuntu1.5"
          },
          {
            "binary_name": "samba-vfs-modules",
            "binary_version": "2:4.11.6+dfsg-0ubuntu1.5"
          },
          {
            "binary_name": "smbclient",
            "binary_version": "2:4.11.6+dfsg-0ubuntu1.5"
          },
          {
            "binary_name": "winbind",
            "binary_version": "2:4.11.6+dfsg-0ubuntu1.5"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:20.04:LTS",
        "name": "samba",
        "purl": "pkg:deb/ubuntu/samba@2:4.11.6+dfsg-0ubuntu1.5?arch=source\u0026distro=focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2:4.11.6+dfsg-0ubuntu1.5"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2:4.10.7+dfsg-0ubuntu2",
        "2:4.10.7+dfsg-0ubuntu3",
        "2:4.11.1+dfsg-3ubuntu1",
        "2:4.11.1+dfsg-3ubuntu2",
        "2:4.11.1+dfsg-3ubuntu4",
        "2:4.11.5+dfsg-1ubuntu1",
        "2:4.11.5+dfsg-1ubuntu2",
        "2:4.11.6+dfsg-0ubuntu1",
        "2:4.11.6+dfsg-0ubuntu1.1",
        "2:4.11.6+dfsg-0ubuntu1.2",
        "2:4.11.6+dfsg-0ubuntu1.3",
        "2:4.11.6+dfsg-0ubuntu1.4"
      ]
    }
  ],
  "aliases": [],
  "details": "Tom Tervoort discovered that the Netlogon protocol implemented by Samba\nincorrectly handled the authentication scheme. A remote attacker could use\nthis issue to forge an authentication token and steal the credentials of\nthe domain admin.\n\nWhile a previous security update fixed the issue by changing the \"server\nschannel\" setting to default to \"yes\", instead of \"auto\", which forced a\nsecure netlogon channel, this update provides additional improvements.\n\nFor compatibility reasons with older devices, Samba now allows specifying\nan insecure netlogon configuration per machine. See the following link for\nexamples: https://www.samba.org/samba/security/CVE-2020-1472.html\n\nIn addition, this update adds additional server checks for the protocol\nattack in the client-specified challenge to provide some protection when\n\u0027server schannel = no/auto\u0027 and avoid the false-positive results when\nrunning the proof-of-concept exploit.\n",
  "id": "USN-4559-1",
  "modified": "2026-04-22T07:36:58Z",
  "published": "2020-09-30T13:44:33Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://ubuntu.com/security/notices/USN-4559-1"
    },
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2020-1472"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "summary": "samba update",
  "upstream": [
    "UBUNTU-CVE-2020-1472"
  ]
}



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