GHSA-72wf-hwcq-65h9 CVE-2021-46398 GO-2022-0563
Cross-Site Request Forgery in Filebrowser
High
Go
- Severity
- 8.8 / 10
- High · CVSS 3.1
- Exploit chance (EPSS)
- 6.72%
- Chance of exploitation in the next 30 days. Higher than 93.93% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- CWE-352 Cross-Site Request Forgery (CSRF)
- Fix
2.18.0- Upgrade github.com/filebrowser/filebrowser/v2 to this version or later
Description
A Cross-Site Request Forgery (CSRF) vulnerability exists in Filebrowser < 2.18.0 that allows attackers to create a backdoor user with admin privilege and get access to the filesystem via a malicious HTML webpage that is sent to the victim.
Affected versions
Go
| Package | Vulnerable | Fixed in |
|---|---|---|
| github.com/filebrowser/filebrowser/v2 | < 2.18.0 |
2.18.0 |
How to fix
Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.
github.com/filebrowser/filebrowser/v2 Go → 2.18.0
- go
go get github.com/filebrowser/filebrowser/v2@v2.18.0 && go mod tidy
Severity breakdown
CVSS 3.1 8.8
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Weakness
CWE-352: Cross-Site Request Forgery (CSRF)
The web application does not, or cannot, sufficiently verify whether a request was intentionally provided by the user who sent the request, which could have originated from an unauthorized actor.
How to prevent it
- Architecture and Design: Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid [REF-1482]. For example, use anti-CSRF packages such as the OWASP CSRFGuard. [REF-330] Another example is the ESAPI Session Management control, which includes a component for CSRF. [REF-45]
- Implementation: Ensure that the application is free of cross-site scripting issues (CWE-79), because most CSRF defenses can be bypassed using attacker-controlled script.
- Architecture and Design: Generate a unique nonce for each form, place the nonce into the form, and verify the nonce upon receipt of the form. Be sure that the nonce is not predictable (CWE-330). [REF-332]
- Architecture and Design: Identify especially dangerous operations. When the user performs a dangerous operation, send a separate confirmation request to ensure that the user intended to perform that operation.
- Architecture and Design: Use the "double-submitted cookie" method as described by Felten and Zeller: When a user visits a site, the site should generate a pseudorandom value and set it as a cookie on the user's machine. The site should require every form submission to include this value as a form value and also as a cookie value. When a POST request is sent to the site, the request should only be considered valid if the form value and the cookie value are the same. Because of the same-origin policy, an attacker cannot read or modify the value stored in the cookie. To successfully submit a form on behalf of the user, the attacker would have to correctly guess the pseudorandom value. If the pseudorandom value is cryptographically strong, this will be prohibitively difficult. This technique requires Javascript, so it may not work for browsers that have Javascript disabled. [REF-331]
- Architecture and Design: Do not use the GET method for any request that triggers a state change.
- Implementation: Check the HTTP Referer header to see if the request originated from an expected page. This could break legitimate functionality, because users or proxies may have disabled sending the Referer for privacy reasons.
References
Advisories
Other links
- github.com/filebrowser/filebrowser/issues/1621
- github.com/filebrowser/filebrowser/commit/74b7cd8e81840537a8206317344f118093153e8d
- febin0x4e4a.blogspot.com/2022/01/critical-csrf-in-filebrowser.html
- febin0x4e4a.wordpress.com/2022/01/19/critical-csrf-in-filebrowser
- febinj.medium.com/critical-csrf-to-rce-in-filebrowser-865a3c34b8e7
- github.com/filebrowser/filebrowser
- pkg.go.dev/vuln/GO-2022-0563
- systemweakness.com/critical-csrf-to-rce-in-filebrowser-865a3c34b8e7
- packetstormsecurity.com/files/165885/FileBrowser-2.17.2-Code-Execution-Cross-Site-Request-Fo…
Timeline
- Published
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| GHSA-833g-cqhp-h72j File Browser: Share API exposes the password hash and bypass token | Low | Also affects github.com/filebrowser/filebrowser/v2 |
| GHSA-83xp-526h-j3ww File Browser: Archive builder turns backslash filenames into path traversal (zip-slip) | Medium | Also affects github.com/filebrowser/filebrowser/v2 |
| GHSA-7rc3-g7h6-22m7 File Browser: Colliding username normalization gives two users the same home directory | High | Also affects github.com/filebrowser/filebrowser/v2 |
| GHSA-8wc8-hf36-mjh9 File Browser: ScopedFs follows a dangling symlink on write, letting a scoped user create files outside their scope | Medium | Also affects github.com/filebrowser/filebrowser/v2 |
| GHSA-fmm7-x4gx-8jhr File Browser: Out-of-scope file deletion by a Create-only scoped user via symlink-following RemoveAll in upload failure-cleanup | High | Also affects github.com/filebrowser/filebrowser/v2 |
| GHSA-xqp3-jq6g-x3qm File Browser: Authentication Bypass via Proxy Auth Header Forgery | Critical | Also affects github.com/filebrowser/filebrowser/v2 |
| GHSA-m93h-4hw7-5qcm File Browser: Command Injection via Authentication Hook Shell Substitution (Pre-Authentication RCE) | Critical | Also affects github.com/filebrowser/filebrowser/v2 |
| GHSA-8c9q-7855-wfxq File Browser has a Command Execution Allowlist Bypass via Shell Metacharacter Injection | High | Also affects github.com/filebrowser/filebrowser/v2 |
Credits: Febin
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