Pulse Secure Client For Windows Local Privilege Escalation

Red Timmy Sec has discovered that Pulse Secure Client for Windows suffers from a local privilege escalation vulnerability in the PulseSecureService.exe service.

MD5 | 660c4ebfc56db61522849dc8876a9d7d

Pulse Secure is recognized among the top 10 Network Access Control (NAC) 
vendors by global revenue market share. The company declares that "80%
of Fortune 500 trust its VPN products by protecting over 20 million

At Red Timmy Security we have discovered that Pulse Secure Client for
Windows suffers of a local privilege escalation vulnerability in the
“PulseSecureService.exe” service. Exploiting this issue allows an
attacker to trick “PulseSecureService.exe” into running an arbitrary
Microsoft Installer executable (“.msi”) with SYSTEM privileges, granting
them administrative rights.

The vulnerability lies in the “dsInstallerService” component, which
provides non-administrative users the ability to install or update new
components using installers provided by Pulse Secure. While
“dsInstallerService” performs a signature verification on the content of
the installer, it has been found that it’s possible to bypass the check
providing the service with a legit Pulse Secure installer and swapping
it with a malicious one after the verification

We have registered CVE-2020-13162 for this vulnerability.

Full story here:

Disclosure Timeline
Vulnerability discovered: April 13th, 2020
Vendor contacted: April 15th, 2020
Vendor's reply: April 17th, 2020
Vendor patch released: May 22nd, 2020
Red Timmy Disclosure: June 16th, 2020

Bug discovered by: Giuseppe Calì
Exploit by: Marco Ortisi & Giuseppe Calì

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