pysec-2020-42
Vulnerability from pysec
Published
2020-06-02 21:15
Modified
2020-06-03 13:47
Details

An issue was discovered in fastecdsa before 2.1.2. When using the NIST P-256 curve in the ECDSA implementation, the point at infinity is mishandled. This means that for an extreme value in k and s^-1, the signature verification fails even if the signature is correct. This behavior is not solely a usability problem. There are some threat models where an attacker can benefit by successfully guessing users for whom signature verification will fail.

Impacted products
Name purl
fastecdsa pkg:pypi/fastecdsa
Aliases


To clipboard 

{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "fastecdsa",
        "purl": "pkg:pypi/fastecdsa"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "4a16daeaf139be20654ef58a9fe4c79dc030458c"
            },
            {
              "fixed": "7b64e3efaa806b4daaf73bb5172af3581812f8de"
            },
            {
              "fixed": "e592f106edd5acf6dacedfab2ad16fe6c735c9d1"
            }
          ],
          "repo": "https://github.com/AntonKueltz/fastecdsa",
          "type": "GIT"
        },
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2.1.2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.0.0b1",
        "1.0.1b1",
        "1.0.1b2",
        "1.0.1b3",
        "1.0.1",
        "1.0.2",
        "1.0.3",
        "1.1.0",
        "1.1.1",
        "1.1.2",
        "1.1.3",
        "1.2.1",
        "1.3.1",
        "1.3.2",
        "1.4.1",
        "1.4.2",
        "1.4.3",
        "1.5.1",
        "1.5.2",
        "1.6.1",
        "1.6.2",
        "1.6.3",
        "1.6.4",
        "1.6.5",
        "1.7.0",
        "1.7.1",
        "1.7.2",
        "1.7.3",
        "1.7.4",
        "1.7.5",
        "2.0.0",
        "2.1.0",
        "2.1.1"
      ]
    }
  ],
  "aliases": [
    "CVE-2020-12607",
    "GHSA-56wv-2wr9-3h9r"
  ],
  "details": "An issue was discovered in fastecdsa before 2.1.2. When using the NIST P-256 curve in the ECDSA implementation, the point at infinity is mishandled. This means that for an extreme value in k and s^-1, the signature verification fails even if the signature is correct. This behavior is not solely a usability problem. There are some threat models where an attacker can benefit by successfully guessing users for whom signature verification will fail.",
  "id": "PYSEC-2020-42",
  "modified": "2020-06-03T13:47:00Z",
  "published": "2020-06-02T21:15:00Z",
  "references": [
    {
      "type": "FIX",
      "url": "https://github.com/AntonKueltz/fastecdsa/commit/4a16daeaf139be20654ef58a9fe4c79dc030458c"
    },
    {
      "type": "FIX",
      "url": "https://github.com/AntonKueltz/fastecdsa/commit/7b64e3efaa806b4daaf73bb5172af3581812f8de"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/AntonKueltz/fastecdsa/issues/52"
    },
    {
      "type": "FIX",
      "url": "https://github.com/AntonKueltz/fastecdsa/commit/e592f106edd5acf6dacedfab2ad16fe6c735c9d1"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/advisories/GHSA-56wv-2wr9-3h9r"
    }
  ]
}


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