TippingPoint Zero Day Initiative

Advantech WebAccess gChkUser ChkAdminViewUsrPwd SQL Injection Authentication Bypass Vulnerability

ZDI-18-064: January 5th, 2018


CVSS Score

Affected Vendors

Affected Products

Vulnerability Details

This vulnerability allows remote attackers to bypass authentication on vulnerable installations of Advantech WebAccess.

The specific flaw exists within the ChkAdminViewUsrPwd method of the gChkUser.asp servlet, called by the gmap.asp servlet. When parsing the user and proj parameters, the process does not properly validate user-supplied strings before using them to construct SQL queries. An attacker can leverage this in conjunction with other vulnerabilities to execute code in the context of the database.

Vendor Response

Advantech has issued an update to correct this vulnerability. More details can be found at:

Disclosure Timeline

    2017-12-01 - Vulnerability reported to vendor
    2018-01-05 - Coordinated public release of advisory


This vulnerability was discovered by: