GHSA-h828-v5pv-33qx CVE-2022-2837
coreDNS vulnerable to Improper Restriction of Communication Channel to Intended Endpoints
Medium
Go
- Severity
- 6.1 / 10
- Medium · CVSS 3.1
- Exploit chance (EPSS)
- 0.39%
- Chance of exploitation in the next 30 days. Higher than 32.94% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- CWE-601 URL Redirection to Untrusted Site ('Open Redirect')
- CWE-923 Improper Restriction of Communication Channel to Intended Endpoints
- Fix
- None yet
- No fixed version published
Description
A flaw was found in coreDNS. This flaw allows a malicious user to redirect traffic intended for external top-level domains (TLD) to a pod they control by creating projects and namespaces that match the TLD.
Affected versions
Go
| Package | Vulnerable | Fixed in |
|---|---|---|
| github.com/coredns/coredns | <= 1.9.3 |
No fix yet |
How to fix
No fixed version has been published yet. Until one is, remove or replace the package, or turn off or isolate the affected feature. This page updates when a fix ships.
Severity breakdown
CVSS 3.1 6.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- Required
- Scope
- Changed
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
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].
CWE-923: Improper Restriction of Communication Channel to Intended Endpoints
The product establishes a communication channel to (or from) an endpoint for privileged or protected operations, but it does not properly ensure that it is communicating with the correct endpoint.
References
Advisories
Packages
Other links
Timeline
- Published
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| GHSA-9gm5-9rfh-m6vx CoreDNS DoH/DoQ/gRPC bypass UPDATE rejection enforced on UDP/TCP | High | Also affects github.com/coredns/coredns |
| GHSA-mrg3-qvqr-jw29 CoreDNS: Unauthenticated memory exhaustion in custom transports | High | Also affects github.com/coredns/coredns |
| GHSA-74w3-63xv-x9mv CoreDNS `k8s_external` headless AXFR can emit an empty transfer batch that panics the `transfer` plugin | Low | Also affects github.com/coredns/coredns |
| GHSA-vp29-5652-4fw9 CoreDNS has TSIG authentication bypass on gRPC and QUIC transports | Critical | Also affects github.com/coredns/coredns |
| GHSA-qhmp-q7xh-99rh CoreDNS has TSIG authentication bypass on DoT, DoH, DoH3, DoQ, and gRPC | High | Also affects github.com/coredns/coredns |
| GHSA-h8mm-c463-wjq3 CoreDNS' transfer stanza selection uses lexicographic compare (subzone ACL bypass) | High | Also affects github.com/coredns/coredns |
| GHSA-63cw-r7xf-jmwr CoreDNS DoH GET oversized dns= query parameter causes pre-validation CPU and memory amplification | High | Also affects github.com/coredns/coredns |
| GHSA-2wpx-qpw2-g5h5 CoreDNS' DoQ worker pool does not bound stream backlog | High | Also affects github.com/coredns/coredns |
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