Facebook Google Plus Twitter LinkedIn YouTube RSS Menu Search Resource - BlogResource - WebinarResource - ReportResource - Eventicons_066 icons_067icons_068icons_069icons_070

PsExec Local Privilege Escalation

Medium

Synopsis

Local Privilege Escalation

This is due to the PsExec service component (PsExecSvc.exe) and how it uses its "\\.\pipe\PSEXESVC" named pipe. A low privileged attacker is able to create a named pipe with the same name before PsExecSvc starts on the machine. Once PsExecSvc starts and calls "CreateNamedPipe," a handle of the existing named pipe is obtained which still has the ACL's from the low privileged attacker, thus allowing the low privileged attacker to read/write to this pipe being used by PsExecSvc (which should be Administrator/System only). In this case, a low privileged attacker can execute any process locally as SYSTEM through this pipe. This vulnerability can be exploited on the target machine in either local or remote PsExec usage scenarios.

Solution

There is no known solution or mitigation for this issue.

Proof of Concept

https://github.com/tenable/poc/blob/master/Microsoft/Sysinternals/PsExecEscalate.cpp

Disclosure Timeline

9-10-2020 - Tenable discloses issue to Microsoft MSRC.
9-10-2020 - Automated MSRC response.
9-16-2020 - MSRC confirms behavior, continues to investigate solution.
9-30-2020 - Tenable follows up asking if there is an expected patch date.
10-08-2020 - Microsoft responds that they are still looking into possible solution.
10-22-2020 - Tenable asks for update on solution.
10-22-2020 - MSRC responds that they are figuring out a way to automatically mitigate the issue.
11-02-2020 - Tenable asks if patch will be for Windows or PsExec.
11-02-2020 - MSRC expects patch to be for PsExec.
11-13-2020 - Tenable asks if there is a planned CVE for this issue.
11-23-2020 - Tenable reminds that disclosure will be December 9, 2020 and asks for update on previous email.
12-04-2020 - Tenable follows up again, asking if there will be CVE assigned and latest patch status.
12-08-2020 - MSRC says they do not plan to issue a CVE, as they don't typically release them for affected product. Asks if Tenable could share advisory draft before release.
12-08-2020 - Tenable asks Microsoft why they does not plan to issue a CVE for this particular issue. Tenable explains we do not typically share drafts before disclosure dates.

All information within TRA advisories is provided “as is”, without warranty of any kind, including the implied warranties of merchantability and fitness for a particular purpose, and with no guarantee of completeness, accuracy, or timeliness. Individuals and organizations are responsible for assessing the impact of any actual or potential security vulnerability.

Tenable takes product security very seriously. If you believe you have found a vulnerability in one of our products, we ask that you please work with us to quickly resolve it in order to protect customers. Tenable believes in responding quickly to such reports, maintaining communication with researchers, and providing a solution in short order.

For more details on submitting vulnerability information, please see our Vulnerability Reporting Guidelines page.

If you have questions or corrections about this advisory, please email [email protected]

Try for Free Buy Now
Tenable.io FREE FOR 30 DAYS

Enjoy full access to a modern, cloud-based vulnerability management platform that enables you to see and track all of your assets with unmatched accuracy. Sign up now.

Tenable.io BUY

Enjoy full access to a modern, cloud-based vulnerability management platform that enables you to see and track all of your assets with unmatched accuracy. Purchase your annual subscription today.

65 assets

Choose Your Subscription Option:

Buy Now
Try for Free Buy Now

Try Nessus Professional Free

FREE FOR 7 DAYS

Nessus® is the most comprehensive vulnerability scanner on the market today. Nessus Professional will help automate the vulnerability scanning process, save time in your compliance cycles and allow you to engage your IT team.

Buy Nessus Professional

Nessus® is the most comprehensive vulnerability scanner on the market today. Nessus Professional will help automate the vulnerability scanning process, save time in your compliance cycles and allow you to engage your IT team.

Buy a multi-year license and save. Add Advanced Support for access to phone, community and chat support 24 hours a day, 365 days a year. Full details here.

Try for Free Buy Now

Try Tenable.io Web Application Scanning

FREE FOR 30 DAYS

Enjoy full access to our latest web application scanning offering designed for modern applications as part of the Tenable.io platform. Safely scan your entire online portfolio for vulnerabilities with a high degree of accuracy without heavy manual effort or disruption to critical web applications. Sign up now.

Buy Tenable.io Web Application Scanning

Enjoy full access to a modern, cloud-based vulnerability management platform that enables you to see and track all of your assets with unmatched accuracy. Purchase your annual subscription today.

5 FQDNs

$3,578

Buy Now

Try for Free Contact Sales

Try Tenable.io Container Security

FREE FOR 30 DAYS

Enjoy full access to the only container security offering integrated into a vulnerability management platform. Monitor container images for vulnerabilities, malware and policy violations. Integrate with continuous integration and continuous deployment (CI/CD) systems to support DevOps practices, strengthen security and support enterprise policy compliance.

Buy Tenable.io Container Security

Tenable.io Container Security seamlessly and securely enables DevOps processes by providing visibility into the security of container images – including vulnerabilities, malware and policy violations – through integration with the build process.

Get a Demo

Get a Demo of Tenable.sc

Please fill out the form below with your contact information and a sales representative will contact you shortly to schedule a demo. You may also include a short comment (limited to 255 characters). Please note that fields with asterisks (*) are mandatory.

Try for Free Contact Sales

Try Tenable Lumin

FREE FOR 30 DAYS

Visualize and explore your Cyber Exposure, track risk reduction over time and benchmark against your peers with Tenable Lumin.

Buy Tenable Lumin

Contact a Sales Representative to see how Lumin can help you gain insight across your entire organization and manage cyber risk.

Request a Demo

Request a demo of Tenable.ot

Get the Operational Technology Security You Need.
Reduce the Risk You Don’t.

Request a Demo

Tenable.ad

Continuously detect and respond to Active Directory attacks. No agents. No privileges. On-prem and in the cloud.