FKIE_CVE-2023-29383

Vulnerability from fkie_nvd - Published: 2023-04-14 22:15 - Updated: 2025-11-03 20:16
Severity ?
3.3 (Low) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
Summary
In Shadow 4.13, it is possible to inject control characters into fields provided to the SUID program chfn (change finger). Although it is not possible to exploit this directly (e.g., adding a new user fails because \n is in the block list), it is possible to misrepresent the /etc/passwd file when viewed. Use of \r manipulations and Unicode characters to work around blocking of the : character make it possible to give the impression that a new user has been added. In other words, an adversary may be able to convince a system administrator to take the system offline (an indirect, social-engineered denial of service) by demonstrating that "cat /etc/passwd" shows a rogue user account.
References
cve@mitre.orghttps://github.com/shadow-maint/shadow/commit/e5905c4b84d4fb90aefcd96ee618411ebfac663dPatch
cve@mitre.orghttps://github.com/shadow-maint/shadow/pull/687Issue Tracking
cve@mitre.orghttps://www.trustwave.com/en-us/resources/blogs/spiderlabs-blog/cve-2023-29383-abusing-linux-chfn-to-misrepresent-etc-passwd/Exploit, Third Party Advisory
cve@mitre.orghttps://www.trustwave.com/en-us/resources/security-resources/security-advisories/?fid=31797Exploit, Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108https://github.com/shadow-maint/shadow/commit/e5905c4b84d4fb90aefcd96ee618411ebfac663dPatch
af854a3a-2127-422b-91ae-364da2661108https://github.com/shadow-maint/shadow/pull/687Issue Tracking
af854a3a-2127-422b-91ae-364da2661108https://lists.debian.org/debian-lts-announce/2025/04/msg00026.html
af854a3a-2127-422b-91ae-364da2661108https://www.trustwave.com/en-us/resources/blogs/spiderlabs-blog/cve-2023-29383-abusing-linux-chfn-to-misrepresent-etc-passwd/Exploit, Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108https://www.trustwave.com/en-us/resources/security-resources/security-advisories/?fid=31797Exploit, Third Party Advisory
Impacted products
Vendor Product Version
shadow_project shadow 4.13
To clipboard 

{
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:shadow_project:shadow:4.13:*:*:*:*:*:*:*",
              "matchCriteriaId": "79B0C1D0-9CF5-451D-B3B3-750B64FD7575",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In Shadow 4.13, it is possible to inject control characters into fields provided to the SUID program chfn (change finger). Although it is not possible to exploit this directly (e.g., adding a new user fails because \\n is in the block list), it is possible to misrepresent the /etc/passwd file when viewed. Use of \\r manipulations and Unicode characters to work around blocking of the : character make it possible to give the impression that a new user has been added. In other words, an adversary may be able to convince a system administrator to take the system offline (an indirect, social-engineered denial of service) by demonstrating that \"cat /etc/passwd\" shows a rogue user account."
    }
  ],
  "id": "CVE-2023-29383",
  "lastModified": "2025-11-03T20:16:01.283",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "NONE",
          "baseScore": 3.3,
          "baseSeverity": "LOW",
          "confidentialityImpact": "NONE",
          "integrityImpact": "LOW",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 1.4,
        "source": "nvd@nist.gov",
        "type": "Primary"
      }
    ]
  },
  "published": "2023-04-14T22:15:07.680",
  "references": [
    {
      "source": "cve@mitre.org",
      "tags": [
        "Patch"
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      "url": "https://github.com/shadow-maint/shadow/commit/e5905c4b84d4fb90aefcd96ee618411ebfac663d"
    },
    {
      "source": "cve@mitre.org",
      "tags": [
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      "url": "https://github.com/shadow-maint/shadow/pull/687"
    },
    {
      "source": "cve@mitre.org",
      "tags": [
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    },
    {
      "source": "cve@mitre.org",
      "tags": [
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      "url": "https://www.trustwave.com/en-us/resources/security-resources/security-advisories/?fid=31797"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "tags": [
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      ],
      "url": "https://github.com/shadow-maint/shadow/commit/e5905c4b84d4fb90aefcd96ee618411ebfac663d"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "tags": [
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      "url": "https://github.com/shadow-maint/shadow/pull/687"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "url": "https://lists.debian.org/debian-lts-announce/2025/04/msg00026.html"
    },
    {
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      "tags": [
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      "url": "https://www.trustwave.com/en-us/resources/blogs/spiderlabs-blog/cve-2023-29383-abusing-linux-chfn-to-misrepresent-etc-passwd/"
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      "tags": [
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        "Third Party Advisory"
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    }
  ],
  "sourceIdentifier": "cve@mitre.org",
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-74"
        }
      ],
      "source": "nvd@nist.gov",
      "type": "Primary"
    },
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-125"
        }
      ],
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "type": "Secondary"
    }
  ]
}


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  • Confirmed: The vulnerability has been validated from an analyst's perspective.
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  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



Detection rules are retrieved from Rulezet.