Vulnerabilities > CVE-2023-39347 - Insufficient Verification of Data Authenticity vulnerability in Cilium
Summary
Cilium is a networking, observability, and security solution with an eBPF-based dataplane. An attacker with the ability to update pod labels can cause Cilium to apply incorrect network policies. This issue arises due to the fact that on pod update, Cilium incorrectly uses user-provided pod labels to select the policies which apply to the workload in question. This can affect Cilium network policies that use the namespace, service account or cluster constructs to restrict traffic, Cilium clusterwide network policies that use Cilium namespace labels to select the Pod and Kubernetes network policies. Non-existent construct names can be provided, which bypass all network policies applicable to the construct. For example, providing a pod with a non-existent namespace as the value of the `io.kubernetes.pod.namespace` label results in none of the namespaced CiliumNetworkPolicies applying to the pod in question. This attack requires the attacker to have Kubernetes API Server access, as described in the Cilium Threat Model. This issue has been resolved in: Cilium versions 1.14.2, 1.13.7, and 1.12.14. Users are advised to upgrade. As a workaround an admission webhook can be used to prevent pod label updates to the `k8s:io.kubernetes.pod.namespace` and `io.cilium.k8s.policy.*` keys.
Vulnerable Configurations
Common Weakness Enumeration (CWE)
Common Attack Pattern Enumeration and Classification (CAPEC)
- JSON Hijacking (aka JavaScript Hijacking) An attacker targets a system that uses JavaScript Object Notation (JSON) as a transport mechanism between the client and the server (common in Web 2.0 systems using AJAX) to steal possibly confidential information transmitted from the server back to the client inside the JSON object by taking advantage of the loophole in the browser's Same Origin Policy that does not prohibit JavaScript from one website to be included and executed in the context of another website. An attacker gets the victim to visit his or her malicious page that contains a script tag whose source points to the vulnerable system with a URL that requests a response from the server containing a JSON object with possibly confidential information. The malicious page also contains malicious code to capture the JSON object returned by the server before any other processing on it can take place, typically by overriding the JavaScript function used to create new objects. This hook allows the malicious code to get access to the creation of each object and transmit the possibly sensitive contents of the captured JSON object to the attackers' server. There is nothing in the browser's security model to prevent the attackers' malicious JavaScript code (originating from attacker's domain) to set up an environment (as described above) to intercept a JSON object response (coming from the vulnerable target system's domain), read its contents and transmit to the attackers' controlled site. The same origin policy protects the domain object model (DOM), but not the JSON.
- Cache Poisoning An attacker exploits the functionality of cache technologies to cause specific data to be cached that aids the attackers' objectives. This describes any attack whereby an attacker places incorrect or harmful material in cache. The targeted cache can be an application's cache (e.g. a web browser cache) or a public cache (e.g. a DNS or ARP cache). Until the cache is refreshed, most applications or clients will treat the corrupted cache value as valid. This can lead to a wide range of exploits including redirecting web browsers towards sites that install malware and repeatedly incorrect calculations based on the incorrect value.
- DNS Cache Poisoning A domain name server translates a domain name (such as www.example.com) into an IP address that Internet hosts use to contact Internet resources. An attacker modifies a public DNS cache to cause certain names to resolve to incorrect addresses that the attacker specifies. The result is that client applications that rely upon the targeted cache for domain name resolution will be directed not to the actual address of the specified domain name but to some other address. Attackers can use this to herd clients to sites that install malware on the victim's computer or to masquerade as part of a Pharming attack.
- Cross-Site Scripting Using MIME Type Mismatch An attacker creates a file with scripting content but where the specified MIME type of the file is such that scripting is not expected. Some browsers will detect that the specified MIME type of the file does not match the actual type of the content and will automatically switch to using an interpreter for the real content type. If the browser does not invoke script filters before doing this, the attackers' script may run on the target unsanitized. For example, the MIME type text/plain may be used where the actual content is text/javascript or text/html. Since text does not contain scripting instructions, the stated MIME type would indicate that filtering is unnecessary. However, if the target application subsequently determines the file's real type and invokes the appropriate interpreter, scripted content could be invoked. In another example, img tags in HTML content could reference a renderable type file instead of an expected image file. The file extension and MIME type can describe an image file, but the file content can be text/javascript or text/html resulting in script execution. If the browser assumes all references in img tags are images, and therefore do not need to be filtered for scripts, this would bypass content filters. In a cross-site scripting attack, the attacker tricks the victim into accessing a URL that uploads a script file with an incorrectly specified MIME type. If the victim's browser switches to the appropriate interpreter without filtering, the attack will execute as a standard XSS attack, possibly revealing the victim's cookies or executing arbitrary script in their browser.
- Spoofing of UDDI/ebXML Messages An attacker spoofs a UDDI, ebXML, or similar message in order to impersonate a service provider in an e-business transaction. UDDI, ebXML, and similar standards are used to identify businesses in e-business transactions. Among other things, they identify a particular participant, WSDL information for SOAP transactions, and supported communication protocols, including security protocols. By spoofing one of these messages an attacker could impersonate a legitimate business in a transaction or could manipulate the protocols used between a client and business. This could result in disclosure of sensitive information, loss of message integrity, or even financial fraud.