CVE-2019-11510: Proof of Concept Available for Arbitrary File Disclosure in Pulse Connect Secure

Scott Caveza

A proof of concept has been made public for CVE-2019-11510, an arbitrary file disclosure vulnerability found in popular virtual private network software, Pulse Connect Secure.

Background

On April 24, Pulse Secure released a security advisory (later amended to include CVEs on the 25th) and patch for multiple critical and high severity vulnerabilities. The issues were identified in Pulse Connect Secure (PCS), previously known as Juniper SSL Virtual Private Network (VPN), a widely used commercial VPN solution. The issues were found by Orange Tsai and Meh Chang from the DEVCORE research team who shared details on the subject at their Black Hat and DEF CON talks earlier this month in Las Vegas.

Among the most severe issues reported is CVE-2019-11510, an arbitrary file disclosure vulnerability. This flaw could allow an unauthenticated, remote attacker to read the contents of files found on a vulnerable device, including sensitive information such as configuration settings.

Analysis

In order to exploit the issue, an attacker can send a malicious HTTP request containing directory traversal sequences along with a crafted Uniform Resource Identifier (URI) and access any file on the device. This provides the attacker access to sensitive device information, and as the researchers describe in their initial report of the issue, this attack could be chained with other vulnerabilities they discovered.

When a user logs into the admin interface of the VPN, their plain-text password is stored in /data/runtime/mtmp/lmdb/dataa/data.mdb. Using the method described above, the attacker could obtain the file, extract the user’s password, and log into the device. Once logged in, the attacker can take advantage of CVE-2019-11539, a command injection vulnerability in the administrative web interface. Alternatively, with the user’s credentials in hand, the attacker could exploit CVE-2019-11508, a vulnerability in the Network File Share (NFS), which allows an authenticated user to upload a malicious file and write arbitrary files to the host.

This research demonstrates how an attacker can take advantage of a pre-authentication flaw and achieve command execution by chaining multiple vulnerabilities to compromise a vulnerable device. What is most concerning about these chained exploits is that PCS is used to restrict external access to an environment, and by achieving command execution on the device, an attacker could use this access to weaponize the device and use it for malicious purposes such as data exfiltration.

If the attacker is not able to find cached credentials, they can access the file /data/runtime/mtmp/system to gather a list of users and hashed passwords. With enough time, effort, and processing power, an attacker could crack the hashes, giving them the ability to log in with the stolen credentials.

Adding to the concern over the potential to exploit these flaws, a Shodan search lists more than 42,000 devices that may be affected if proper patches have not yet been applied.

Image source: https://www.shodan.io

A breakdown of the CVEs and the PCS versions affected are outlined below:

CVE CVSSv3 (Vendor Assigned) NVD CVSSv3 Score Tenable VPR Versions of Pulse Connect Secure Affected CVE-2019-11510 10 (AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N) 8.8 (AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H) 9.9 9.0RX, 8.3RX, 8.2RX Note: 8.1RX and below are not directly impacted CVE-2019-11508 9.9 (AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H) 7.2 (AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H) 5.9 9.0RX, 8.3RX, 8.2RX, 8.1RX CVE-2019-11540 8.3 (AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:H) 9.8 (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H) 6.7 9.0RX, 8.3RX CVE-2019-11543 8.3 (AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:H) 6.1 (AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N 3 9.0RX, 8.3RX, 8.1RX CVE-2019-11541 8.3 (AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:L) 7.5 (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N) 3.6 9.0RX, 8.3RX, 8.2RX CVE-2019-11542 8.0 (AV:N/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H) 7.2 (AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H) 5.9 9.0RX, 8.3RX, 8.2RX, 8.1RX CVE-2019-11539 8.0 (AV:N/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H) 7.2 (AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H) 8.4 9.0RX, 8.3RX, 8.2RX, 8.1RX CVE-2019-11538 7.7 (AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N) 7.7 (AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N) 4.4 9.0RX 8.3RX 8.2RX 8.1RX CVE-2019-11509 6.4 (AV:N/AC:H/PR:H/UI:R/S:U/C:H/I:H/A:H) 8.8 (AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H) 5.9 9.0RX 8.3RX 8.2RX 8.1RX CVE-2019-11507 5.8 (AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:L) 6.1 (AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N) 3 9.0RX 8.3RX

* Please note Tenable VPR scores are calculated nightly. This blog was updated on August 29 to reflect current VPR scores.

Proof of concept

A proof of concept (PoC) was published to the Exploit Database on August 20 as an exploit module written by Alyssa Herrera and Justin Wagner.

Solution

Pulse Secure has published a security advisory with information on each of the CVEs reported. Patching solutions are listed below:

Version installed Fixed release Pulse Connect Secure 9.0RX Pulse Connect Secure 9.0R3.4 & 9.0R4 Pulse Connect Secure 8.3RX Pulse Connect Secure 8.3R7.1 Pulse Connect Secure 8.2RX Pulse Connect Secure 8.2R12.1 Pulse Connect Secure 8.1RX Pulse Connect Secure 8.1R15.1

Identifying affected systems

A list of Tenable plugins to identify these vulnerabilities is listed here including a direct exploit check for CVE-2019-11510 (Plugin ID 127897).

Get more information

Join Tenable's Security Response Team on the Tenable Community.

Learn more about Tenable, the first Cyber Exposure platform for holistic management of your modern attack surface. Get a free 60-day trial of Tenable.io.

Read more >

Published on Aug 21, 2019

People also viewed

Business Cost Analyst - Cloud Infrastructure

San Jose California United States E Santa Clara St., San Jose, California, United States, 95113 Engineering Engineering
Your Role:Tenable is seeking a Business Cost Analyst of Cloud Infrastructure with strong MS Excel experience to assess, analyze and compile current costs and potentially determine initiatives to reduce and improve our cloud infrastructure cost for...

Professional Services Engagement Manager

Singapore Singapore Singapore North Bridge Road, Parkview Square, Singapore, 188788 Professional Services Professional Services
Your Role:The Professional Services Engagement Manager assists in the professional services business development and oversees the delivery of projects. The Professional Services Engagement Manager’s roles include tactical project management oversi...

UX Designer

Columbia Maryland United States Columbia Gateway Drive, Columbia, Maryland, United States, 21046 Engineering Engineering
Your Role:Tenable is looking for an extraordinary Senior UX Designer to join our team. Our group is chartered with creating the next generation of security products while at the same time pioneering unprecedented user experience in the digital sec...

Commercial Territory Manager - West

Columbia Maryland United States Columbia Gateway Drive, Columbia, Maryland, United States, 21046 Sales Sales
Your Role:The Commercial Territory Manager will meet and exceed quarterly sales quota by developing new opportunities within specific geographical territory.  Researching and identifying potential accounts; outbound cold calling to soliciting new ...

Senior Software Engineer (Java & Kotlin)

San Jose California United States E Santa Clara St., San Jose, California, United States, 95113 Engineering Engineering
Your Role:Tenable is looking for a Senior Software Engineer to join the Lumin product development team. As a Sr. Software Engineer you will drive projects end-to-end, collaborate on product requirements with Product Managers, architect and impleme...

Public Sector Channel Manager - Distribution

Reston Virginia United States Reston, Virginia, United States Channel Sales Sales
Your Role:The Public Sector Channel Manager-Distribution is responsible for establishing and managing relationships with the Distribution Partner(s).  The CM-Disty will act as a sales liaison between distributor and Tenable Channel Manager personn...

We have big plans for continued global growth, and we’re looking for people who are creative, flexible and dedicated to helping us build something great – something that matters.