Executive Summary

Title Pulse Connect Secure contains a use-after-free vulnerability
Name VU#213092 First vendor Publication 2021-04-20
Vendor VU-CERT Last vendor Modification 2021-05-19
Severity (Vendor) N/A Revision M

Security-Database Scoring CVSS v3

Cvss vector : CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
Overall CVSS Score 10
Base Score 10 Environmental Score 10
impact SubScore 6 Temporal Score 10
Exploitabality Sub Score 3.9
Attack Vector Network Attack Complexity Low
Privileges Required None User Interaction None
Scope Changed Confidentiality Impact High
Integrity Impact High Availability Impact High
Calculate full CVSS 3.0 Vectors scores

Security-Database Scoring CVSS v2

Cvss vector : (AV:N/AC:L/Au:N/C:P/I:P/A:P)
Cvss Base Score 7.5 Attack Range Network
Cvss Impact Score 6.4 Attack Complexity Low
Cvss Expoit Score 10 Authentication None Required
Calculate full CVSS 2.0 Vectors scores



Pulse Connect Secure (PCS) gateway contains a use-after-free vulnerability that can allow an unauthenticated remote attacker to execute arbitrary code.



A use-after-free vulnerability that can be reached via a license server handling endpoint may allow a remote, unauthenticated attacker to execute arbitrary code on a vulnerable Pulse Connect Secure gateway system.

Every system that is running PCS 9.0R3 or higher or 9.1R1 through 9.2R11.3 is affected. Having the license server configuration enabled is NOT a prerequisite to being vulnerable. The vulnerable endpoints are present regardless of whether the system is an actual license server or not.

This vulnerability is being exploited in the wild.


By making a crafted request to a vulnerable Pulse Connect Secure system, an unauthenticated remote attacker may be able to execute arbitrary code on the gateway with root privileges.


Apply an update

This vulnerability and others are addressed in Pulse Connect Secure 9.1R11.4.

Apply a workaround

If you are not using the features that the following workaround disables, we recommend applying the XML workaround even on systems that have been upgraded to 9.1R11.4 to reduce attack surface. Pulse Secure has published a Workaround-2104.xml file that contains mitigations to protect against this and other vulnerabilities. Importing this XML workaround will activate the protections immediately and does not require any downtime for the VPN system. This workaround will block requests that match the following URI patterns:

^/+dana/+meeting ^/+dana/+fb/+smb ^/+dana-cached/+fb/+smb ^/+dana-ws/+namedusers ^/+dana-ws/+metric 

Note that installing this workaround will block the ability to use the following features:

  • Windows File Share Browser
  • Pulse Secure Collaboration
  • License Server

Instead of using the workaround to protect a PCS that is being used as a license server, we recommend updating such systems to PCS 9.1R11.4. If this is not possible, restrict which IP addresses are allowed to communicate with the system.

Run the PCS Integrity Assurance utility

A PCS administrator should run the PCS Integrity Assurance utility to help determine if a system has evidence that it has been compromised. Please be aware of two limitations of this tool:

  1. Upon completion of the Integrity Assurance tool, the PCS device will automatically reboot.
  2. Because running the Integrity Assurance tool relies on the use of the administrative web interface of the PCS device itself, it is reasonable to assume that it may be possible for a compromised device to display misleading results.

Enable Unauthenticated Request logging

By default, PCS devices do not log unauthenticated web requests. Additionally, the administrative interface for a PCS device will warn that: Selecting this can quickly fill up User access log space in case of attack.

Because this vulnerability is exploitable via an unauthenticated request to the PCS, evidence of exploitation may only be present if the "Unauthenticated Requests" logging option is enabled. Enable this feature in the PCS administrative web interface by visiting: System -> Log/Monitoring -> User Access -> Settings and enabling the "Unauthenticated Requests" option.

Enable remote logging

Attackers who have compromised a PCS device may delete on-device logs in the process. For this reason, configure a remote Syslog server to ensure that PCS log entries are not modified or deleted.


This vulnerability was publicly reported by Pulse Secure with additional details and context published by Fireye.

This document was written by Chuck Yarbrough and Will Dormann.

Original Source

Url : https://kb.cert.org/vuls/id/213092

CWE : Common Weakness Enumeration

% Id Name
100 % CWE-416 Use After Free

CPE : Common Platform Enumeration

Application 36

Alert History

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Date Informations
2021-09-23 17:17:46
  • Multiple Updates
2021-05-19 17:17:37
  • Multiple Updates
2021-05-08 00:17:35
  • Multiple Updates
2021-05-07 21:18:00
  • Multiple Updates
2021-05-06 21:17:58
  • Multiple Updates
2021-05-05 21:17:57
  • Multiple Updates
2021-04-21 17:17:17
  • Multiple Updates
2021-04-21 00:17:15
  • First insertion