CVE-2020-5233: Github.com/oauth2 proxy/oauth2 proxy The Pattern '/\domain.com' Is Not Vulnerability
MODERATECVE-2020-5233 is a MODERATE (CVSS 5.9) the pattern '/\domain.com' is not vulnerability (CWE-601: URL Redirection to Untrusted Site ('Open Redirect')) affecting Github.com/oauth2 proxy/oauth2 proxy libraries in the Go ecosystem. The issue involves the pattern '/\domain.com' is not disallowed when redirecting, allowing for open redirect. Remediation is available by upgrading affected packages to version 5.0.0.
CVE-2020-5233 at a Glance
Security Impact
CVSS: 5.9
The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:L/I:H/A:L).
How to Fix CVE-2020-5233
To remediate this vulnerability, upgrade all affected Github.com/oauth2 proxy/oauth2 proxy dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.
Upgrade github.com/oauth2-proxy/oauth2-proxy to 5.0.0Run the following command in your project directory to verify that all resolved dependencies use the patched release:
inspect dependencies for github.com/oauth2-proxy/oauth2-proxyHow to Check if You Are Affected
To determine whether your application is affected by CVE-2020-5233, inspect your project dependencies for Github.com/oauth2 proxy/oauth2 proxy:
inspect dependencies for github.com/oauth2-proxy/oauth2-proxyAnalyze the terminal output to locate any version of Github.com/oauth2 proxy/oauth2 proxy in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 5.0.0), your application is affected.
Note: Verify declared build manifests and deployed runtime container environments.
Technical Details
Vulnerability Mechanism & Technical Analysis
This vulnerability is classified under CWE-601: URL Redirection to Untrusted Site ('Open Redirect'), where the web application accepts a user-controlled input that specifies a link to an external site, and uses that link in a redirect. In Github.com/oauth2 proxy/oauth2 proxy, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.
Source Advisory Statement
CVE-2020-5233 Affected Github.com/oauth2 proxy/oauth2 proxy Versions
1 component(s)| Product / Package | Ecosystem | Affected Versions | Fixed Version |
|---|---|---|---|
|
github.com/oauth2-proxy/oauth2-proxy
|
Go |
< 5.0.0
|
5.0.0
|
References
Frequently Asked Questions
What is CVE-2020-5233?
Which Github.com/oauth2 proxy/oauth2 proxy versions are affected?
What version fixes CVE-2020-5233?
Is github.com/oauth2-proxy/oauth2-proxy affected?
What is the CVSS score of CVE-2020-5233?
What CWE is associated with CVE-2020-5233?
How can I check Go dependencies for CVE-2020-5233?
Machine-readable OSV JSON
OSV v1.5 Schema
{
"schema_version" : "1.4.0",
"id" : "GHSA-qqxw-m5fj-f7gv",
"modified" : "2021-05-24T21:20:17Z",
"published" : "2021-12-20T18:02:38Z",
"aliases" : [ "CVE-2020-5233" ],
"summary" : "The pattern '/\\domain.com' is not disallowed when redirecting, allowing for open redirect",
"details" : "### Impact\nAn open redirect vulnerability has been found in `oauth2_proxy`. Anyone who uses `oauth2_proxy` may potentially be impacted. \n\nFor a context [detectify] have an in depth blog post about the potential impact of an open redirect. Particularly see the OAuth section.\n\n**tl;dr**: People's authentication tokens could be silently harvested by an attacker. e.g:\n`facebook.com/oauth.php?clientid=123&state=abc&redirect_url=https://yourdomain.com/red.php?url%3dhttps://attacker.com/`\n\n### Patches\n\n@sauyon found the issue, and has submitted a patch. \n\n```\ndiff --git a/oauthproxy.go b/oauthproxy.go\nindex 72ab580..f420df6 100644\n--- a/oauthproxy.go\n+++ b/oauthproxy.go\n@@ -517,7 +517,7 @@ func (p *OAuthProxy) GetRedirect(req *http.Request) (redirect string, err error)\n // IsValidRedirect checks whether the redirect URL is whitelisted\n func (p *OAuthProxy) IsValidRedirect(redirect string) bool {\n \tswitch {\n-\tcase strings.HasPrefix(redirect, \"/\") && !strings.HasPrefix(redirect, \"//\"):\n+\tcase strings.HasPrefix(redirect, \"/\") && !strings.HasPrefix(redirect, \"//\") && !strings.HasPrefix(redirect, \"/\\\\\"):\n \t\treturn true\n \tcase strings.HasPrefix(redirect, \"http://\") || strings.HasPrefix(redirect, \"https://\"):\n \t\tredirectURL, err := url.Parse(redirect)\n```\n\nThis patch will be applied to the next release, which is scheduled for when this is publicly disclosed.\n\n### Workarounds\n\nAt this stage there is no work around.",
"severity" : [ {
"type" : "CVSS_V3",
"score" : "CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:L/I:H/A:L"
} ],
"affected" : [ {
"package" : {
"ecosystem" : "Go",
"name" : "github.com/oauth2-proxy/oauth2-proxy"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "0"
}, {
"fixed" : "5.0.0"
} ]
} ]
} ],
"references" : [ {
"type" : "WEB",
"url" : "https://github.com/oauth2-proxy/oauth2-proxy/security/advisories/GHSA-qqxw-m5fj-f7gv"
}, {
"type" : "ADVISORY",
"url" : "https://nvd.nist.gov/vuln/detail/CVE-2020-5233"
}, {
"type" : "WEB",
"url" : "https://github.com/oauth2-proxy/oauth2_proxy/commit/a316f8a06f3c0ca2b5fc5fa18a91781b313607b2"
}, {
"type" : "WEB",
"url" : "https://blog.detectify.com/2019/05/16/the-real-impact-of-an-open-redirect"
}, {
"type" : "WEB",
"url" : "https://github.com/oauth2-proxy/oauth2_proxy/releases/tag/v5.0.0"
} ],
"database_specific" : {
"cwe_ids" : [ "CWE-601" ],
"severity" : "MODERATE",
"github_reviewed" : true,
"github_reviewed_at" : "2021-05-24T21:20:17Z",
"nvd_published_at" : null
}
}