CVE-2021-22893

CVE Published	2021-04-23
Related CWE(s)	CWE-287: Improper Authentication, CWE-416: Use After Free
Related Vendor(s)	pulsesecure, ivanti
Related Product(s)	connect_secure, pulse_connect_secure
Exploitation Reported (CISA KEV)	2021-11-03
CVSS 3 Base Score	10.0 (CRITICAL)
CVSS 3 Attack Complexity	LOW
CVSS 3 Attack Vector	NETWORK

Pulse Connect Secure 9.0R3/9.1R1 and higher is vulnerable to an authentication bypass vulnerability exposed by the Windows File Share Browser and Pulse Secure Collaboration features of Pulse Connect Secure that can allow an unauthenticated user to perform remote arbitrary code execution on the Pulse Connect Secure gateway. This vulnerability has been exploited in the wild.

Cyber Threat Graph Context

Explore how this CVE relates to the wider threat graph

Threat Reports Related to CVE-2021-22893

Report

Suspected APT Actors Leverage Authentication Bypass Techniques and Pulse Secure Zero-Day

Reporting from Mandiant which discusses the exploitation of Pulse Secure VPN devices in 2021 and 12 malware families associated with the campaign. ...

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Associated CAPEC Patterns

Token Impersonation (CAPEC-633)

An adversary exploits a weakness in authentication to create an access token (or equivalent) that impersonates a different entity, and then associates a process/thread to that that impersonated token. This action causes a downstream user to make a decision or take action that is based on the assumed identity, and not the response that blocks the adversary.

Upload a Web Shell to a Web Server (CAPEC-650)

By exploiting insufficient permissions, it is possible to upload a web shell to a web server in such a way that it can be executed remotely. This shell can have various capabilities, thereby acting as a "gateway" to the underlying web server. The shell might execute at the higher permission level of the web server, providing the ability the execute malicious code at elevated levels.

Fake the Source of Data (CAPEC-194)

An adversary takes advantage of improper authentication to provide data or services under a falsified identity. The purpose of using the falsified identity may be to prevent traceability of the provided data or to assume the rights granted to another individual. One of the simplest forms of this attack would be the creation of an email message with a modified "From" field in order to appear that the message was sent from someone other than the actual sender. The root of the attack (in this case the email system) fails to properly authenticate the source and this results in the reader incorrectly performing the instructed action. Results of the attack vary depending on the details of the attack, but common results include privilege escalation, obfuscation of other attacks, and data corruption/manipulation.

Exploiting Trust in Client (CAPEC-22)

An attack of this type exploits vulnerabilities in client/server communication channel authentication and data integrity. It leverages the implicit trust a server places in the client, or more importantly, that which the server believes is the client. An attacker executes this type of attack by communicating directly with the server where the server believes it is communicating only with a valid client. There are numerous variations of this type of attack.

Session Hijacking (CAPEC-593)

This type of attack involves an adversary that exploits weaknesses in an application's use of sessions in performing authentication. The adversary is able to steal or manipulate an active session and use it to gain unathorized access to the application.

Authentication Abuse (CAPEC-114)

An attacker obtains unauthorized access to an application, service or device either through knowledge of the inherent weaknesses of an authentication mechanism, or by exploiting a flaw in the authentication scheme's implementation. In such an attack an authentication mechanism is functioning but a carefully controlled sequence of events causes the mechanism to grant access to the attacker.

Identity Spoofing (CAPEC-151)

Identity Spoofing refers to the action of assuming (i.e., taking on) the identity of some other entity (human or non-human) and then using that identity to accomplish a goal. An adversary may craft messages that appear to come from a different principle or use stolen / spoofed authentication credentials.

Authentication Bypass (CAPEC-115)

An attacker gains access to application, service, or device with the privileges of an authorized or privileged user by evading or circumventing an authentication mechanism. The attacker is therefore able to access protected data without authentication ever having taken place.

Adversary in the Middle (AiTM) (CAPEC-94)

An adversary targets the communication between two components (typically client and server), in order to alter or obtain data from transactions. A general approach entails the adversary placing themself within the communication channel between the two components.

Utilizing REST's Trust in the System Resource to Obtain Sensitive Data (CAPEC-57)

This attack utilizes a REST(REpresentational State Transfer)-style applications' trust in the system resources and environment to obtain sensitive data once SSL is terminated.

References

CVE.org

View more information about CVE-2021-22893 on the official MITRE CVE website.

NIST National Vulnerability Database

CVE-2021-22893 on the NIST NVD.

CISA Known Exploited Vulnerabilities