Synopsis
While researching Advantech WebAccess 8.3.1, Tenable discovered that CVE-2017-16720 was not patched. The vulnerability, originally found by Steven Seeley and disclosed by ZDI, was supposed to have been patched in WebAccess 8.3 according to ICS-CERT advisory ICSA-18-04-02. However, Tenable has concluded that no patch for this vulnerability has ever been released. Since Tenable first rediscovered CVE-2017-16720, WebAccess 8.3.2 has been released, and it also remains unpatched.
The vulnerability exists due to the way the DsDaqWebService in drawsrv.dll handles IOCTL value 0x2711. When DsDaqWebService handles the IOCTL an attacker controlled string is eventually passed to the Windows function CreateProcessA as the lpCommandLine parameter.
Having an unpatched unauthenticated remote code execution vulnerability in any product is never desirable, but the issue is compounded due to the public exploit that was released on March 12, 2018. Due to the unusual history of this vulnerability, Tenable opted to follow a 45-day disclosure timeline.
Solution
No solution currently exists.Additional References
https://www.zerodayinitiative.com/advisories/ZDI-18-024/https://ics-cert.us-cert.gov/advisories/ICSA-18-004-02A
https://medium.com/tenable-techblog/advantech-webaccess-unpatched-rce-ffe9f37f8b83
Disclosure Timeline
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