CVE-2020-15111: Github.com/gofiber/fiber CRLF Vulnerability Vulnerability
MODERATECVE-2020-15111 is a MODERATE (CVSS 4.2) crlf vulnerability vulnerability (CWE-74: Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')) affecting Github.com/gofiber/fiber libraries in the Go ecosystem. The issue involves crlf vulnerability in fiber. Remediation is available by upgrading affected packages to version 1.12.6.
CVE-2020-15111 at a Glance
Security Impact
CVSS: 4.2
The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N).
How to Fix CVE-2020-15111
To remediate this vulnerability, upgrade all affected Github.com/gofiber/fiber 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/gofiber/fiber to 1.12.6
Run the following command in your project directory to verify that all resolved dependencies use the patched release:
inspect dependencies for github.com/gofiber/fiber
How to Check if You Are Affected
To determine whether your application is affected by CVE-2020-15111, inspect your project dependencies for Github.com/gofiber/fiber:
inspect dependencies for github.com/gofiber/fiber
Analyze the terminal output to locate any version of Github.com/gofiber/fiber in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 1.12.6), 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-74: Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection'), where the product constructs all or part of a command, data structure, or record using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify how it is parsed or interpreted when it is sent to a downstream component. In Github.com/gofiber/fiber, 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-2020-15111 Affected Github.com/gofiber/fiber Versions
1 component(s)| Product / Package | Ecosystem | Affected Versions | Fixed Version |
|---|---|---|---|
|
github.com/gofiber/fiber
|
Go |
< 1.12.6
|
1.12.6
|
References
Frequently Asked Questions
What is CVE-2020-15111?
Which Github.com/gofiber/fiber versions are affected?
What version fixes CVE-2020-15111?
Is github.com/gofiber/fiber affected?
What is the CVSS score of CVE-2020-15111?
What CWE is associated with CVE-2020-15111?
How can I check Go dependencies for CVE-2020-15111?
Machine-readable OSV JSON
OSV v1.5 Schema
{
"schema_version" : "1.4.0",
"id" : "GHSA-9cx9-x2gp-9qvh",
"modified" : "2023-02-09T17:46:27Z",
"published" : "2021-06-29T21:24:28Z",
"aliases" : [ "CVE-2020-15111" ],
"summary" : "CRLF vulnerability in Fiber",
"details" : "### Impact\nThe filename that is given in [c.Attachment()](https://docs.gofiber.io/ctx#attachment) is not escaped, and therefore vulnerable for a CRLF injection attack. I.e. an attacker could upload a custom filename and then give the link to the victim. With this filename, the attacker can change the name of the downloaded file, redirect to another site, change the authorization header, etc.\n\n### Steps to reproduce\n```go\npackage main\n\nimport \"github.com/gofiber/fiber\"\n\nconst badFileName = \"another secret document.pdf\\\"\\r\\nLocation: google.com\\r\\nAuthorization: \\\"example_of_session_fixation\"\n\nfunc splitTheResponse(c *fiber.Ctx) {\n\tc.Attachment(badFileName)\n}\n\nfunc main() {\n\tapp := fiber.New()\n\tapp.Get(\"/attack\", splitTheResponse)\n\tapp.Listen(\"127.0.0.1:8080\")\n}\n```\n```\nHTTP/1.1 200 OK\nDate: Fri, 10 Jul 2020 19:47:04 GMT\nContent-Type: application/octet-stream\nContent-Length: 0\nContent-Disposition: attachment; filename=\"another secret document.pdf\"\nLocation: google.com\nAuthorization: \"example_of_session_fixation\"\n```\n\n### Patches\nThis issue has been patched in `v1.12.6` with commit [579](https://github.com/gofiber/fiber/pull/579/commits/f698b5d5066cfe594102ae252cd58a1fe57cf56f) escaping the filename by default.\n\n### Workarounds\nYou could of course serialize the input yourself before passing it to `ctx.Attachment()`, this is actually a good practice by default. But in case you forget, we got you covered 👍 \n\n### References\nA CRLF injection attack is one of several types of injection attacks. It can be used to escalate to more malicious attacks such as Cross-site Scripting (XSS), page injection, web cache poisoning, cache-based defacement, and more. A CRLF injection vulnerability exists if an attacker can inject the CRLF characters into a web application, for example using a user input form or an HTTP request, [see acunetix](https://www.acunetix.com/websitesecurity/crlf-injection/)\n\n### For more information\nIf you have any questions or comments about this advisory:\n* Open an issue in [gofiber/fiber](https://github.com/gofiber/fiber)\n* Join us on [Discord](https://gofiber.io/discord)",
"severity" : [ {
"type" : "CVSS_V3",
"score" : "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N"
} ],
"affected" : [ {
"package" : {
"ecosystem" : "Go",
"name" : "github.com/gofiber/fiber"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "0"
}, {
"fixed" : "1.12.6"
} ]
} ]
} ],
"references" : [ {
"type" : "WEB",
"url" : "https://github.com/gofiber/fiber/security/advisories/GHSA-9cx9-x2gp-9qvh"
}, {
"type" : "ADVISORY",
"url" : "https://nvd.nist.gov/vuln/detail/CVE-2020-15111"
}, {
"type" : "WEB",
"url" : "https://github.com/gofiber/fiber/pull/579"
}, {
"type" : "WEB",
"url" : "https://github.com/gofiber/fiber/commit/f698b5d5066cfe594102ae252cd58a1fe57cf56f"
}, {
"type" : "PACKAGE",
"url" : "https://github.com/gofiber/fiber"
}, {
"type" : "WEB",
"url" : "https://pkg.go.dev/vuln/GO-2021-0108"
} ],
"database_specific" : {
"cwe_ids" : [ "CWE-74", "CWE-93" ],
"severity" : "MODERATE",
"github_reviewed" : true,
"github_reviewed_at" : "2021-05-24T19:14:18Z",
"nvd_published_at" : "2020-07-20T18:15:00Z"
}
}