GHSA-hxmp-8f47-x9fc CVE-2011-4294

Moodle Open Redirect Via Error Messages

Medium Packagist

Severity: Medium; The publisher's own rating, not a CVSS score
Exploit chance (EPSS): 1.54%; Chance of exploitation in the next 30 days. Higher than 74.94% of scored vulnerabilities.
Known exploited: No; Not in CISA's catalog
Weakness: CWE-601 URL Redirection to Untrusted Site ('Open Redirect')
Fix: 1.9.13; Upgrade moodle/moodle to this version or later

Description

The error-message functionality in Moodle 1.9.x before 1.9.13, 2.0.x before 2.0.4, and 2.1.x before 2.1.1 does not ensure that a continuation link refers to an http or https URL for the local Moodle instance, which might allow attackers to trick users into visiting arbitrary web sites via error message links that lead offsite.

Affected versions

Packagist

Package	Vulnerable	Fixed in
moodle/moodle	`< 1.9.13`	`1.9.13`
moodle/moodle	`>= 2.0, < 2.0.4`	`2.0.4`
moodle/moodle	`>= 2.1, < 2.1.1`	`2.1.1`

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.

moodle/moodle Packagist → `1.9.13`

composer

composer require moodle/moodle:^1.9.13

Weakness

CWE-601: URL Redirection to Untrusted Site ('Open Redirect')

The web application accepts a user-controlled input that specifies a link to an external site, and uses that link in a redirect.

How to prevent it

Implementation: Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does. When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, "boat" may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as "red" or "blue." Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code's environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright. Use a list of approved URLs or domains to be used for redirection.
Architecture and Design: Use an intermediate disclaimer page that provides the user with a clear warning that they are leaving the current site. Implement a long timeout before the redirect occurs, or force the user to click on the link. Be careful to avoid XSS problems (CWE-79) when generating the disclaimer page.
Architecture and Design: When the set of acceptable objects, such as filenames or URLs, is limited or known, create a mapping from a set of fixed input values (such as numeric IDs) to the actual filenames or URLs, and reject all other inputs. For example, ID 1 could map to "/login.asp" and ID 2 could map to "http://www.example.com/". Features such as the ESAPI AccessReferenceMap [REF-45] provide this capability.
Architecture and Design: Ensure that no externally-supplied requests are honored by requiring that all redirect requests include a unique nonce generated by the application [REF-483]. Be sure that the nonce is not predictable (CWE-330).
Architecture and Design, Implementation: Understand all the potential areas where untrusted inputs can enter your software: parameters or arguments, cookies, anything read from the network, environment variables, reverse DNS lookups, query results, request headers, URL components, e-mail, files, filenames, databases, and any external systems that provide data to the application. Remember that such inputs may be obtained indirectly through API calls. Many open redirect problems occur because the programmer assumed that certain inputs could not be modified, such as cookies and hidden form fields.
Operation: Use an application firewall that can detect attacks against this weakness. It can be beneficial in cases in which the code cannot be fixed (because it is controlled by a third party), as an emergency prevention measure while more comprehensive software assurance measures are applied, or to provide defense in depth [REF-1481].

References

Advisories

nvd.nist.gov/vuln/detail/CVE-2011-4294

Packages

github.com/moodle/moodle

Timeline

May 13, 2022 Published
Jan 17, 2024 Last updated by the source
Nov 1, 2026 Latest EPSS score

Advisory	Severity	Why it's related
GHSA-cg8j-5cr2-568q Moodle TeX formula editor is vulnerable to DoS through lack of execution time limits	Medium	Also affects moodle/moodle
GHSA-ggxq-2mg9-8966 Moodle has a Remote Code Execution risk via file restore	High	Also affects moodle/moodle
GHSA-8jrv-wx83-w3xj Moodle Inserts Sensitive Information Into Sent Data	Medium	Also affects moodle/moodle
GHSA-hcm6-q6pc-xfhm Moodle has an authorization logic flaw	Critical	Also affects moodle/moodle
GHSA-vwhw-vp9v-q9c9 Moodle vulnerable to Cross-site Scripting	Medium	Also affects moodle/moodle
GHSA-5cx4-w4fh-fr57 Moodle Affected by Improper Restriction of Excessive Authentication Attempts	High	Also affects moodle/moodle
GHSA-qv78-6gpp-hm68 Moodle Open Redirect vulnerability	Medium	Also affects moodle/moodle
GHSA-qfh6-h7j6-fvjv Moodle formula injection vulnerability	High	Also affects moodle/moodle

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