CVE-2020-27780 (GCVE-0-2020-27780)
Vulnerability from cvelistv5 – Published: 2020-12-17 23:55 – Updated: 2024-08-04 16:25
VLAI
EPSS
VEX
Summary
A flaw was found in Linux-Pam in versions prior to 1.5.1 in the way it handle empty passwords for non-existing users. When the user doesn't exist PAM try to authenticate with root and in the case of an empty password it successfully authenticate.
Severity
9.8 (Critical)
CWE
Assigner
References
1 reference
| URL | Tags |
|---|---|
| https://bugzilla.redhat.com/show_bug.cgi?id=1901094 | x_refsource_MISC |
{
"containers": {
"adp": [
{
"providerMetadata": {
"dateUpdated": "2024-08-04T16:25:42.438Z",
"orgId": "af854a3a-2127-422b-91ae-364da2661108",
"shortName": "CVE"
},
"references": [
{
"tags": [
"x_refsource_MISC",
"x_transferred"
],
"url": "https://bugzilla.redhat.com/show_bug.cgi?id=1901094"
}
],
"title": "CVE Program Container"
}
],
"cna": {
"affected": [
{
"product": "pam",
"vendor": "n/a",
"versions": [
{
"status": "affected",
"version": "pam 1.5.1"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "A flaw was found in Linux-Pam in versions prior to 1.5.1 in the way it handle empty passwords for non-existing users. When the user doesn\u0027t exist PAM try to authenticate with root and in the case of an empty password it successfully authenticate."
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-287",
"description": "CWE-287",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2020-12-17T23:55:45.000Z",
"orgId": "53f830b8-0a3f-465b-8143-3b8a9948e749",
"shortName": "redhat"
},
"references": [
{
"tags": [
"x_refsource_MISC"
],
"url": "https://bugzilla.redhat.com/show_bug.cgi?id=1901094"
}
],
"x_legacyV4Record": {
"CVE_data_meta": {
"ASSIGNER": "secalert@redhat.com",
"ID": "CVE-2020-27780",
"STATE": "PUBLIC"
},
"affects": {
"vendor": {
"vendor_data": [
{
"product": {
"product_data": [
{
"product_name": "pam",
"version": {
"version_data": [
{
"version_value": "pam 1.5.1"
}
]
}
}
]
},
"vendor_name": "n/a"
}
]
}
},
"data_format": "MITRE",
"data_type": "CVE",
"data_version": "4.0",
"description": {
"description_data": [
{
"lang": "eng",
"value": "A flaw was found in Linux-Pam in versions prior to 1.5.1 in the way it handle empty passwords for non-existing users. When the user doesn\u0027t exist PAM try to authenticate with root and in the case of an empty password it successfully authenticate."
}
]
},
"problemtype": {
"problemtype_data": [
{
"description": [
{
"lang": "eng",
"value": "CWE-287"
}
]
}
]
},
"references": {
"reference_data": [
{
"name": "https://bugzilla.redhat.com/show_bug.cgi?id=1901094",
"refsource": "MISC",
"url": "https://bugzilla.redhat.com/show_bug.cgi?id=1901094"
}
]
}
}
}
},
"cveMetadata": {
"assignerOrgId": "53f830b8-0a3f-465b-8143-3b8a9948e749",
"assignerShortName": "redhat",
"cveId": "CVE-2020-27780",
"datePublished": "2020-12-17T23:55:45.000Z",
"dateReserved": "2020-10-27T00:00:00.000Z",
"dateUpdated": "2024-08-04T16:25:42.438Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.1",
"vulnerability-lookup:meta": {
"epss": {
"cve": "CVE-2020-27780",
"date": "2026-10-29",
"epss": "0.01959",
"percentile": "0.80255"
},
"microsoft_vex": {
"current_release_date": "2020-12-23T00:00:00.000Z",
"cve": "CVE-2020-27780",
"id": "msrc_CVE-2020-27780",
"initial_release_date": "2020-12-02T00:00:00.000Z",
"product_status:fixed": "1",
"product_status:known_affected": "1",
"source": "Microsoft CSAF VEX",
"status": "final",
"title": "A flaw was found in Linux-Pam in versions prior to 1.5.1 in the way it handle empty passwords for non-existing users. When the user doesn\u0027t exist PAM try to authenticate with root and in the case of an empty password it successfully authenticate.",
"url": "https://msrc.microsoft.com/csaf/vex/2020/msrc_cve-2020-27780.json",
"version": "1"
},
"nvd": {
"cve": {
"configurations": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:a:linux-pam:linux-pam:*:*:*:*:*:*:*:*",
"matchCriteriaId": "693B7D7D-6BD3-4E5F-9E03-048B5BA832E7",
"versionEndExcluding": "1.5.1",
"versionStartIncluding": "1.5.0",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "A flaw was found in Linux-Pam in versions prior to 1.5.1 in the way it handle empty passwords for non-existing users. When the user doesn\u0027t exist PAM try to authenticate with root and in the case of an empty password it successfully authenticate."
},
{
"lang": "es",
"value": "Se encontr\u00f3 un fallo en Linux-Pam en versiones anteriores a 1.5.1 en la manera en que maneja contrase\u00f1as vac\u00edas para usuarios inexistentes.\u0026#xa0;Cuando el usuario no existe, PAM intenta autenticarse con root y en el caso de una contrase\u00f1a vac\u00eda, es autenticado con \u00e9xito"
}
],
"id": "CVE-2020-27780",
"lastModified": "2024-11-21T05:21:49.307",
"metrics": {
"cvssMetricV2": [
{
"acInsufInfo": false,
"baseSeverity": "HIGH",
"cvssData": {
"accessComplexity": "LOW",
"accessVector": "NETWORK",
"authentication": "NONE",
"availabilityImpact": "COMPLETE",
"baseScore": 10.0,
"confidentialityImpact": "COMPLETE",
"integrityImpact": "COMPLETE",
"vectorString": "AV:N/AC:L/Au:N/C:C/I:C/A:C",
"version": "2.0"
},
"exploitabilityScore": 10.0,
"impactScore": 10.0,
"obtainAllPrivilege": false,
"obtainOtherPrivilege": false,
"obtainUserPrivilege": false,
"source": "nvd@nist.gov",
"type": "Primary",
"userInteractionRequired": false
}
],
"cvssMetricV31": [
{
"cvssData": {
"attackComplexity": "LOW",
"attackVector": "NETWORK",
"availabilityImpact": "HIGH",
"baseScore": 9.8,
"baseSeverity": "CRITICAL",
"confidentialityImpact": "HIGH",
"integrityImpact": "HIGH",
"privilegesRequired": "NONE",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
"version": "3.1"
},
"exploitabilityScore": 3.9,
"impactScore": 5.9,
"source": "nvd@nist.gov",
"type": "Primary"
}
]
},
"published": "2020-12-18T00:15:14.330",
"references": [
{
"source": "secalert@redhat.com",
"tags": [
"Issue Tracking",
"Third Party Advisory"
],
"url": "https://bugzilla.redhat.com/show_bug.cgi?id=1901094"
},
{
"source": "af854a3a-2127-422b-91ae-364da2661108",
"tags": [
"Issue Tracking",
"Third Party Advisory"
],
"url": "https://bugzilla.redhat.com/show_bug.cgi?id=1901094"
}
],
"sourceIdentifier": "secalert@redhat.com",
"vulnStatus": "Modified",
"weaknesses": [
{
"description": [
{
"lang": "en",
"value": "CWE-287"
}
],
"source": "secalert@redhat.com",
"type": "Secondary"
}
]
}
},
"redhat_vex": {
"aggregate_severity": "Moderate",
"current_release_date": "2025-11-21T16:59:12+00:00",
"cve": "CVE-2020-27780",
"id": "CVE-2020-27780",
"initial_release_date": "2020-10-27T00:00:00+00:00",
"product_status:known_not_affected": "10",
"source": "Red Hat CSAF VEX",
"status": "final",
"title": "pam: authentication bypass when the user doesn\u0027t exist and root password is blank",
"url": "https://security.access.redhat.com/data/csaf/v2/vex/2020/cve-2020-27780.json",
"version": "3"
}
}
}
Loading…
Loading…
Drag nodes to arrange them. Double-click a related vulnerability to open it, or a source to visit its link. The Physics button on the left tunes the layout and the simulation; the legend at the bottom left hides or shows nodes by kind and by sighting type.
Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
Vulnerability timeline
Sightings and recorded dates, grouped by day · UTC
Loading timeline…
Loading…
Loading…
The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
Loading…
Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.