No Fix Planned For LabVIEW Bug, Says National Instruments

Researchers identified a vulnerability in National Instruments’ LabVIEW software that will not receive patch by the vendor.

Automated test equipment and virtual instrumentation software behemoth National Instruments said it will not patch software that security researchers at Cisco Talos said is flawed and could result in code execution by third-party attackers.

The affected software is LabVIEW, a leading program designed for rapid development of engineering applications that require testing, measurement or control.

The vulnerability (CVE-2017-2779) was discovered by Cisco Talos and disclosed to National Instruments in January and impacts LabVIEW 2016 version 16.0.

“Talos is disclosing the presence of a code execution vulnerability which can be triggered by opening specially crafted VI (virtual instrument) files, the proprietary file format used by LabVIEW,” wrote Cisco Talos in a research note posted earlier this week.

Researchers linked the flaw to an exploitable memory corruption bug that exists in the RSRC segment parsing functionality of LabVIEW’s software.

“Although there is no published specification for the file format, inspecting the files shows that they contain a section named ‘RSRC’, presumably containing resource information. Modulating the values within this section of a VI file can cause a controlled looping condition resulting in an arbitrary null write,” according to Martin Lee, technical lead, security research, with Cisco Talos.

Under these conditions an attacker could craft a Virtual Instrument file (.vi) that can be used to trigger the vulnerability, potentially resulting in code execution.

“National Instruments does not consider that this issue constitutes a vulnerability in their product, since any .exe like file format can be modified to replace legitimate content with malicious and has declined to release a patch,” according to the Cisco Talos report.

Lee disagrees with that assessment and compared the risk associated with bug to that of a critical .NET PE loader vulnerability (CVE-2007-0041) patched by Microsoft in 2007. In that instance, remote attackers could execute arbitrary code via what was most likely was a buffer overflow attack involving an “unchecked buffer” and un-validated message lengths in the PE Loader services in Microsoft .NET Framework 1.0, 1.1, and 2.0 for Windows 2000, XP, Server 2003 and Vista.

“Many (LabVIEW) users may be unaware that VI files are analogous to .exe files and should be accorded the same security requirements,” Lee said.

In March, Cisco Talos disclosed a similar memory corruption vulnerability (CVE-2017-2775) to National Instruments which was triggered by opening specially crafted VI files. In that instance, National Instruments released a patch, LabVIEW 2016 f2.

“As with the previous disclosure, organizations should be aware that proprietary file formats without a published specification are nevertheless amenable to inspection to identify vulnerabilities. The consequences of a successful compromise of a system that interacts with the physical world, such as a data acquisition and control systems, may be critical to safety,” Lee said.