GSD-2020-15237
Vulnerability from gsd - Updated: 2020-10-05 00:00Details
### Impact
When using the `derivation_endpoint` plugin, it's possible for the attacker to use a timing attack
to guess the signature of the derivation URL.
### Patches
The problem has been fixed by comparing sent and calculated signature in constant time, using
`Rack::Utils.secure_compare`. Users using the `derivation_endpoint` plugin are urged to upgrade
to Shrine 3.3.0 or greater.
### Workarounds
Users of older Shrine versions can apply the following monkey-patch after loading the `derivation_endpoint` plugin:
```rb
class Shrine
class UrlSigner
def verify_signature(string, signature)
if signature.nil?
fail InvalidSignature, "missing \"signature\" param"
elsif !Rack::Utils.secure_compare(signature, generate_signature(string))
fail InvalidSignature, "provided signature does not match the calculated signature"
end
end
end
end
```
### References
You can read more about timing attacks [here](https://en.wikipedia.org/wiki/Timing_attack).
Aliases
Aliases
{
"GSD": {
"alias": "CVE-2020-15237",
"description": "In Shrine before version 3.3.0, when using the `derivation_endpoint` plugin, it\u0027s possible for the attacker to use a timing attack to guess the signature of the derivation URL. The problem has been fixed by comparing sent and calculated signature in constant time, using `Rack::Utils.secure_compare`. Users using the `derivation_endpoint` plugin are urged to upgrade to Shrine 3.3.0 or greater. A possible workaround is provided in the linked advisory.",
"id": "GSD-2020-15237"
},
"gsd": {
"metadata": {
"exploitCode": "unknown",
"remediation": "unknown",
"reportConfidence": "confirmed",
"type": "vulnerability"
},
"osvSchema": {
"affected": [
{
"package": {
"ecosystem": "RubyGems",
"name": "shrine",
"purl": "pkg:gem/shrine"
}
}
],
"aliases": [
"CVE-2020-15237",
"GHSA-5jjv-x4fq-qjwp"
],
"details": "### Impact\n\nWhen using the `derivation_endpoint` plugin, it\u0027s possible for the attacker to use a timing attack\nto guess the signature of the derivation URL.\n\n### Patches\n\nThe problem has been fixed by comparing sent and calculated signature in constant time, using\n`Rack::Utils.secure_compare`. Users using the `derivation_endpoint` plugin are urged to upgrade\nto Shrine 3.3.0 or greater.\n\n### Workarounds\n\nUsers of older Shrine versions can apply the following monkey-patch after loading the `derivation_endpoint` plugin:\n\n```rb\nclass Shrine\n class UrlSigner\n def verify_signature(string, signature)\n if signature.nil?\n fail InvalidSignature, \"missing \\\"signature\\\" param\"\n elsif !Rack::Utils.secure_compare(signature, generate_signature(string))\n fail InvalidSignature, \"provided signature does not match the calculated signature\"\n end\n end\n end\nend\n```\n\n### References\n\nYou can read more about timing attacks [here](https://en.wikipedia.org/wiki/Timing_attack).",
"id": "GSD-2020-15237",
"modified": "2020-10-05T00:00:00.000Z",
"published": "2020-10-05T00:00:00.000Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/shrinerb/shrine/security/advisories/GHSA-5jjv-x4fq-qjwp"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": 5.9,
"type": "CVSS_V3"
}
],
"summary": "Possible timing attack in derivation_endpoint"
}
},
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"product": {
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"version_value": "\u003c 3.3.0"
}
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"description": {
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"lang": "eng",
"value": "In Shrine before version 3.3.0, when using the `derivation_endpoint` plugin, it\u0027s possible for the attacker to use a timing attack to guess the signature of the derivation URL. The problem has been fixed by comparing sent and calculated signature in constant time, using `Rack::Utils.secure_compare`. Users using the `derivation_endpoint` plugin are urged to upgrade to Shrine 3.3.0 or greater. A possible workaround is provided in the linked advisory."
}
]
},
"impact": {
"cvss": {
"attackComplexity": "HIGH",
"attackVector": "NETWORK",
"availabilityImpact": "NONE",
"baseScore": 5.9,
"baseSeverity": "MEDIUM",
"confidentialityImpact": "HIGH",
"integrityImpact": "NONE",
"privilegesRequired": "NONE",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N",
"version": "3.1"
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"description": [
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"value": "{\"CWE-208\":\"Observable Timing Discrepancy\"}"
}
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"lang": "eng",
"value": "{\"CWE-203\":\"Observable Differences in Behavior to Error Inputs\"}"
}
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"name": "https://github.com/shrinerb/shrine/security/advisories/GHSA-5jjv-x4fq-qjwp",
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},
{
"name": "https://github.com/shrinerb/shrine/commit/1b27090ce31543bf39f186c20ea47c8250fca2f0",
"refsource": "MISC",
"url": "https://github.com/shrinerb/shrine/commit/1b27090ce31543bf39f186c20ea47c8250fca2f0"
}
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},
"source": {
"advisory": "GHSA-5jjv-x4fq-qjwp",
"discovery": "UNKNOWN"
}
},
"github.com/rubysec/ruby-advisory-db": {
"cve": "2020-15237",
"cvss_v3": 5.9,
"date": "2020-10-05",
"description": "### Impact\n\nWhen using the `derivation_endpoint` plugin, it\u0027s possible for the attacker to use a timing attack\nto guess the signature of the derivation URL.\n\n### Patches\n\nThe problem has been fixed by comparing sent and calculated signature in constant time, using\n`Rack::Utils.secure_compare`. Users using the `derivation_endpoint` plugin are urged to upgrade\nto Shrine 3.3.0 or greater.\n\n### Workarounds\n\nUsers of older Shrine versions can apply the following monkey-patch after loading the `derivation_endpoint` plugin:\n\n```rb\nclass Shrine\n class UrlSigner\n def verify_signature(string, signature)\n if signature.nil?\n fail InvalidSignature, \"missing \\\"signature\\\" param\"\n elsif !Rack::Utils.secure_compare(signature, generate_signature(string))\n fail InvalidSignature, \"provided signature does not match the calculated signature\"\n end\n end\n end\nend\n```\n\n### References\n\nYou can read more about timing attacks [here](https://en.wikipedia.org/wiki/Timing_attack).",
"gem": "shrine",
"ghsa": "5jjv-x4fq-qjwp",
"patched_versions": [
"\u003e= 3.3.0"
],
"title": "Possible timing attack in derivation_endpoint",
"url": "https://github.com/shrinerb/shrine/security/advisories/GHSA-5jjv-x4fq-qjwp"
},
"gitlab.com": {
"advisories": [
{
"affected_range": "\u003c3.3.0",
"affected_versions": "All versions before 3.3.0",
"cvss_v2": "AV:N/AC:M/Au:N/C:P/I:N/A:N",
"cvss_v3": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N",
"cwe_ids": [
"CWE-1035",
"CWE-203",
"CWE-208",
"CWE-937"
],
"date": "2020-10-19",
"description": "In Shrine using `Rack::Utils.secure_compare`. Users using the `derivation_endpoint` plugin are urged to upgrade to Shrine or greater. A possible workaround is provided in the linked advisory.",
"fixed_versions": [
"3.3.0"
],
"identifier": "CVE-2020-15237",
"identifiers": [
"CVE-2020-15237",
"GHSA-5jjv-x4fq-qjwp"
],
"not_impacted": "All versions starting from 3.3.0",
"package_slug": "gem/shrine",
"pubdate": "2020-10-05",
"solution": "Upgrade to version 3.3.0 or above.",
"title": "Information Exposure Through Discrepancy",
"urls": [
"https://nvd.nist.gov/vuln/detail/CVE-2020-15237"
],
"uuid": "ad74d5f0-0347-499c-860e-8114996ec2fe"
}
]
},
"nvd.nist.gov": {
"configurations": {
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"cpe_match": [
{
"cpe23Uri": "cpe:2.3:a:shrinerb:shrine:*:*:*:*:*:ruby:*:*",
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"versionEndExcluding": "3.3.0",
"vulnerable": true
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"ID": "CVE-2020-15237"
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"description": {
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"value": "In Shrine before version 3.3.0, when using the `derivation_endpoint` plugin, it\u0027s possible for the attacker to use a timing attack to guess the signature of the derivation URL. The problem has been fixed by comparing sent and calculated signature in constant time, using `Rack::Utils.secure_compare`. Users using the `derivation_endpoint` plugin are urged to upgrade to Shrine 3.3.0 or greater. A possible workaround is provided in the linked advisory."
}
]
},
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"name": "https://github.com/shrinerb/shrine/security/advisories/GHSA-5jjv-x4fq-qjwp",
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}
},
"impact": {
"baseMetricV2": {
"acInsufInfo": false,
"cvssV2": {
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"accessVector": "NETWORK",
"authentication": "NONE",
"availabilityImpact": "NONE",
"baseScore": 4.3,
"confidentialityImpact": "PARTIAL",
"integrityImpact": "NONE",
"vectorString": "AV:N/AC:M/Au:N/C:P/I:N/A:N",
"version": "2.0"
},
"exploitabilityScore": 8.6,
"impactScore": 2.9,
"obtainAllPrivilege": false,
"obtainOtherPrivilege": false,
"obtainUserPrivilege": false,
"severity": "MEDIUM",
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},
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"integrityImpact": "NONE",
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"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N",
"version": "3.1"
},
"exploitabilityScore": 2.2,
"impactScore": 3.6
}
},
"lastModifiedDate": "2020-10-19T13:39Z",
"publishedDate": "2020-10-05T19:15Z"
}
}
}
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Sightings
| Author | Source | Type | Date |
|---|
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.
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