msrc_cve-2020-25682
Vulnerability from csaf_microsoft
Published
2021-01-02 00:00
Modified
2021-01-29 00:00
Summary
A flaw was found in dnsmasq before 2.83. A buffer overflow vulnerability was discovered in the way dnsmasq extract names from DNS packets before validating them with DNSSEC data. An attacker on the network who can create valid DNS replies could use this flaw to cause an overflow with arbitrary data in a heap-allocated memory possibly executing code on the machine. The flaw is in the rfc1035.c:extract_name() function which writes data to the memory pointed by name assuming MAXDNAME*2 bytes are available in the buffer. However in some code execution paths it is possible extract_name() gets passed an offset from the base buffer thus reducing in practice the number of available bytes that can be written in the buffer. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.

Notes

Additional Resources
To determine the support lifecycle for your software, see the Microsoft Support Lifecycle: https://support.microsoft.com/lifecycle
Disclaimer
The information provided in the Microsoft Knowledge Base is provided \"as is\" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.


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{
  "document": {
    "category": "csaf_vex",
    "csaf_version": "2.0",
    "distribution": {
      "text": "Public",
      "tlp": {
        "label": "WHITE",
        "url": "https://www.first.org/tlp/"
      }
    },
    "lang": "en-US",
    "notes": [
      {
        "category": "general",
        "text": "To determine the support lifecycle for your software, see the Microsoft Support Lifecycle: https://support.microsoft.com/lifecycle",
        "title": "Additional Resources"
      },
      {
        "category": "legal_disclaimer",
        "text": "The information provided in the Microsoft Knowledge Base is provided \\\"as is\\\" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.",
        "title": "Disclaimer"
      }
    ],
    "publisher": {
      "category": "vendor",
      "contact_details": "secure@microsoft.com",
      "name": "Microsoft Security Response Center",
      "namespace": "https://msrc.microsoft.com"
    },
    "references": [
      {
        "category": "self",
        "summary": "CVE-2020-25682 A flaw was found in dnsmasq before 2.83. A buffer overflow vulnerability was discovered in the way dnsmasq extract names from DNS packets before validating them with DNSSEC data. An attacker on the network who can create valid DNS replies could use this flaw to cause an overflow with arbitrary data in a heap-allocated memory possibly executing code on the machine. The flaw is in the rfc1035.c:extract_name() function which writes data to the memory pointed by name assuming MAXDNAME*2 bytes are available in the buffer. However in some code execution paths it is possible extract_name() gets passed an offset from the base buffer thus reducing in practice the number of available bytes that can be written in the buffer. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability. - VEX",
        "url": "https://msrc.microsoft.com/csaf/vex/2021/msrc_cve-2020-25682.json"
      },
      {
        "category": "external",
        "summary": "Microsoft Support Lifecycle",
        "url": "https://support.microsoft.com/lifecycle"
      },
      {
        "category": "external",
        "summary": "Common Vulnerability Scoring System",
        "url": "https://www.first.org/cvss"
      }
    ],
    "title": "A flaw was found in dnsmasq before 2.83. A buffer overflow vulnerability was discovered in the way dnsmasq extract names from DNS packets before validating them with DNSSEC data. An attacker on the network who can create valid DNS replies could use this flaw to cause an overflow with arbitrary data in a heap-allocated memory possibly executing code on the machine. The flaw is in the rfc1035.c:extract_name() function which writes data to the memory pointed by name assuming MAXDNAME*2 bytes are available in the buffer. However in some code execution paths it is possible extract_name() gets passed an offset from the base buffer thus reducing in practice the number of available bytes that can be written in the buffer. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.",
    "tracking": {
      "current_release_date": "2021-01-29T00:00:00.000Z",
      "generator": {
        "date": "2025-10-19T21:39:52.593Z",
        "engine": {
          "name": "MSRC Generator",
          "version": "1.0"
        }
      },
      "id": "msrc_CVE-2020-25682",
      "initial_release_date": "2021-01-02T00:00:00.000Z",
      "revision_history": [
        {
          "date": "2021-01-29T00:00:00.000Z",
          "legacy_version": "1",
          "number": "1",
          "summary": "Information published."
        }
      ],
      "status": "final",
      "version": "1"
    }
  },
  "product_tree": {
    "branches": [
      {
        "branches": [
          {
            "branches": [
              {
                "category": "product_version",
                "name": "1.0",
                "product": {
                  "name": "CBL Mariner 1.0",
                  "product_id": "16820"
                }
              }
            ],
            "category": "product_name",
            "name": "Azure Linux"
          },
          {
            "branches": [
              {
                "category": "product_version_range",
                "name": "\u003ccm1 dnsmasq 2.85-1",
                "product": {
                  "name": "\u003ccm1 dnsmasq 2.85-1",
                  "product_id": "1"
                }
              },
              {
                "category": "product_version",
                "name": "cm1 dnsmasq 2.85-1",
                "product": {
                  "name": "cm1 dnsmasq 2.85-1",
                  "product_id": "19065"
                }
              }
            ],
            "category": "product_name",
            "name": "dnsmasq"
          }
        ],
        "category": "vendor",
        "name": "Microsoft"
      }
    ],
    "relationships": [
      {
        "category": "default_component_of",
        "full_product_name": {
          "name": "\u003ccm1 dnsmasq 2.85-1 as a component of CBL Mariner 1.0",
          "product_id": "16820-1"
        },
        "product_reference": "1",
        "relates_to_product_reference": "16820"
      },
      {
        "category": "default_component_of",
        "full_product_name": {
          "name": "cm1 dnsmasq 2.85-1 as a component of CBL Mariner 1.0",
          "product_id": "19065-16820"
        },
        "product_reference": "19065",
        "relates_to_product_reference": "16820"
      }
    ]
  },
  "vulnerabilities": [
    {
      "cve": "CVE-2020-25682",
      "cwe": {
        "id": "CWE-122",
        "name": "Heap-based Buffer Overflow"
      },
      "notes": [
        {
          "category": "general",
          "text": "redhat",
          "title": "Assigning CNA"
        }
      ],
      "product_status": {
        "fixed": [
          "19065-16820"
        ],
        "known_affected": [
          "16820-1"
        ]
      },
      "references": [
        {
          "category": "self",
          "summary": "CVE-2020-25682 A flaw was found in dnsmasq before 2.83. A buffer overflow vulnerability was discovered in the way dnsmasq extract names from DNS packets before validating them with DNSSEC data. An attacker on the network who can create valid DNS replies could use this flaw to cause an overflow with arbitrary data in a heap-allocated memory possibly executing code on the machine. The flaw is in the rfc1035.c:extract_name() function which writes data to the memory pointed by name assuming MAXDNAME*2 bytes are available in the buffer. However in some code execution paths it is possible extract_name() gets passed an offset from the base buffer thus reducing in practice the number of available bytes that can be written in the buffer. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability. - VEX",
          "url": "https://msrc.microsoft.com/csaf/vex/2021/msrc_cve-2020-25682.json"
        }
      ],
      "remediations": [
        {
          "category": "vendor_fix",
          "date": "2021-01-29T00:00:00.000Z",
          "details": "2.85-1:Security Update:https://learn.microsoft.com/en-us/azure/azure-linux/tutorial-azure-linux-upgrade",
          "product_ids": [
            "16820-1"
          ],
          "url": "https://learn.microsoft.com/en-us/azure/azure-linux/tutorial-azure-linux-upgrade"
        }
      ],
      "scores": [
        {
          "cvss_v3": {
            "attackComplexity": "HIGH",
            "attackVector": "NETWORK",
            "availabilityImpact": "HIGH",
            "baseScore": 8.1,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "HIGH",
            "environmentalsScore": 0.0,
            "integrityImpact": "HIGH",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "temporalScore": 8.1,
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "products": [
            "16820-1"
          ]
        }
      ],
      "title": "A flaw was found in dnsmasq before 2.83. A buffer overflow vulnerability was discovered in the way dnsmasq extract names from DNS packets before validating them with DNSSEC data. An attacker on the network who can create valid DNS replies could use this flaw to cause an overflow with arbitrary data in a heap-allocated memory possibly executing code on the machine. The flaw is in the rfc1035.c:extract_name() function which writes data to the memory pointed by name assuming MAXDNAME*2 bytes are available in the buffer. However in some code execution paths it is possible extract_name() gets passed an offset from the base buffer thus reducing in practice the number of available bytes that can be written in the buffer. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability."
    }
  ]
}


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