CVE-2021-4239 Vulnerability Analysis & Exploit Details

CVE-2021-4239 Vulnerability Summary

CVE-2021-4239: The Noise protocol implementation suffers from weakened cryptographic security after encrypting 2^64 messages, and a potential denial of service attack. After 2^64 (~18.4 quintillion) messages are encrypted with the Encrypt function, the nonce counter will wrap around, causing multiple messages to be encrypted with the same key and nonce. In a separate issue, the Decrypt function increments the nonce state even when it fails to decrypt a message. If an attacker can provide an invalid input to the Decrypt function, this will cause the nonce state to desynchronize between the peers, resulting in a failure to encrypt all subsequent messages.

Exploit Prediction Scoring System (EPSS)

The EPSS score estimates the probability that this vulnerability will be exploited in the near future.

EPSS Score: 0.063% (probability of exploit)

EPSS Percentile: 30.29% (lower percentile = lower relative risk)
This vulnerability is less risky than approximately 69.71000000000001% of others.

CVE-2021-4239 References

External References

• https://github.com/flynn/noise/pull/44
• https://pkg.go.dev/vuln/GO-2022-0425
• https://github.com/flynn/noise/pull/44
• https://pkg.go.dev/vuln/GO-2022-0425

CWE Common Weakness Enumeration

CAPEC Common Attack Pattern Enumeration and Classification

• Sniffing Attacks CAPEC-157 In this attack pattern, the adversary intercepts information transmitted between two third parties. The adversary must be able to observe, read, and/or hear the communication traffic, but not necessarily block the communication or change its content. Any transmission medium can theoretically be sniffed if the adversary can examine the contents between the sender and recipient. Sniffing Attacks are similar to Adversary-In-The-Middle attacks (CAPEC-94), but are entirely passive. AiTM attacks are predominantly active and often alter the content of the communications themselves.
• Sniffing Network Traffic CAPEC-158 In this attack pattern, the adversary monitors network traffic between nodes of a public or multicast network in an attempt to capture sensitive information at the protocol level. Network sniffing applications can reveal TCP/IP, DNS, Ethernet, and other low-level network communication information. The adversary takes a passive role in this attack pattern and simply observes and analyzes the traffic. The adversary may precipitate or indirectly influence the content of the observed transaction, but is never the intended recipient of the target information.
• Lifting Sensitive Data Embedded in Cache CAPEC-204 An adversary examines a target application's cache, or a browser cache, for sensitive information. Many applications that communicate with remote entities or which perform intensive calculations utilize caches to improve efficiency. However, if the application computes or receives sensitive information and the cache is not appropriately protected, an attacker can browse the cache and retrieve this information. This can result in the disclosure of sensitive information.
• Accessing/Intercepting/Modifying HTTP Cookies CAPEC-31 This attack relies on the use of HTTP Cookies to store credentials, state information and other critical data on client systems. There are several different forms of this attack. The first form of this attack involves accessing HTTP Cookies to mine for potentially sensitive data contained therein. The second form involves intercepting this data as it is transmitted from client to server. This intercepted information is then used by the adversary to impersonate the remote user/session. The third form is when the cookie's content is modified by the adversary before it is sent back to the server. Here the adversary seeks to convince the target server to operate on this falsified information.
• Retrieve Embedded Sensitive Data CAPEC-37 An attacker examines a target system to find sensitive data that has been embedded within it. This information can reveal confidential contents, such as account numbers or individual keys/credentials that can be used as an intermediate step in a larger attack.
• Harvesting Information via API Event Monitoring CAPEC-383 An adversary hosts an event within an application framework and then monitors the data exchanged during the course of the event for the purpose of harvesting any important data leaked during the transactions. One example could be harvesting lists of usernames or userIDs for the purpose of sending spam messages to those users. One example of this type of attack involves the adversary creating an event within the sub-application. Assume the adversary hosts a "virtual sale" of rare items. As other users enter the event, the attacker records via AiTM (CAPEC-94) proxy the user_ids and usernames of everyone who attends. The adversary would then be able to spam those users within the application using an automated script.
• Application API Message Manipulation via Man-in-the-Middle CAPEC-384 An attacker manipulates either egress or ingress data from a client within an application framework in order to change the content of messages. Performing this attack can allow the attacker to gain unauthorized privileges within the application, or conduct attacks such as phishing, deceptive strategies to spread malware, or traditional web-application attacks. The techniques require use of specialized software that allow the attacker to perform adversary-in-the-middle (CAPEC-94) communications between the web browser and the remote system. Despite the use of AiTH software, the attack is actually directed at the server, as the client is one node in a series of content brokers that pass information along to the application framework. Additionally, it is not true "Adversary-in-the-Middle" attack at the network layer, but an application-layer attack the root cause of which is the master applications trust in the integrity of code supplied by the client.
• Transaction or Event Tampering via Application API Manipulation CAPEC-385 An attacker hosts or joins an event or transaction within an application framework in order to change the content of messages or items that are being exchanged. Performing this attack allows the attacker to manipulate content in such a way as to produce messages or content that look authentic but may contain deceptive links, substitute one item or another, spoof an existing item and conduct a false exchange, or otherwise change the amounts or identity of what is being exchanged. The techniques require use of specialized software that allow the attacker to man-in-the-middle communications between the web browser and the remote system in order to change the content of various application elements. Often, items exchanged in game can be monetized via sales for coin, virtual dollars, etc. The purpose of the attack is for the attack to scam the victim by trapping the data packets involved the exchange and altering the integrity of the transfer process.
• Application API Navigation Remapping CAPEC-386 An attacker manipulates either egress or ingress data from a client within an application framework in order to change the destination and/or content of links/buttons displayed to a user within API messages. Performing this attack allows the attacker to manipulate content in such a way as to produce messages or content that looks authentic but contains links/buttons that point to an attacker controlled destination. Some applications make navigation remapping more difficult to detect because the actual HREF values of images, profile elements, and links/buttons are masked. One example would be to place an image in a user's photo gallery that when clicked upon redirected the user to an off-site location. Also, traditional web vulnerabilities (such as CSRF) can be constructed with remapped buttons or links. In some cases navigation remapping can be used for Phishing attacks or even means to artificially boost the page view, user site reputation, or click-fraud.
• Navigation Remapping To Propagate Malicious Content CAPEC-387 An adversary manipulates either egress or ingress data from a client within an application framework in order to change the content of messages and thereby circumvent the expected application logic.
• Application API Button Hijacking CAPEC-388 An attacker manipulates either egress or ingress data from a client within an application framework in order to change the destination and/or content of buttons displayed to a user within API messages. Performing this attack allows the attacker to manipulate content in such a way as to produce messages or content that looks authentic but contains buttons that point to an attacker controlled destination.
• Signature Spoofing by Mixing Signed and Unsigned Content CAPEC-477 An attacker exploits the underlying complexity of a data structure that allows for both signed and unsigned content, to cause unsigned data to be processed as though it were signed data.
• Cellular Traffic Intercept CAPEC-609 Cellular traffic for voice and data from mobile devices and retransmission devices can be intercepted via numerous methods. Malicious actors can deploy their own cellular tower equipment and intercept cellular traffic surreptitiously. Additionally, government agencies of adversaries and malicious actors can intercept cellular traffic via the telecommunications backbone over which mobile traffic is transmitted.
• Sniff Application Code CAPEC-65 An adversary passively sniffs network communications and captures application code bound for an authorized client. Once obtained, they can use it as-is, or through reverse-engineering glean sensitive information or exploit the trust relationship between the client and server. Such code may belong to a dynamic update to the client, a patch being applied to a client component or any such interaction where the client is authorized to communicate with the server.

Vulnerable Configurations

• cpe:2.3:a:noiseprotocol:noise:-:*:*:*:*:go:*:*
  cpe:2.3:a:noiseprotocol:noise:-:*:*:*:*:go:*:*

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