More than 100 million computers from Dell and other vendors may have been exposed to hacker attacks due to a serious vulnerability in software made by hardware diagnostic tools provider PC-Doctor.
Researchers at cybersecurity firm SafeBreach discovered that the Dell SupportAssist software preinstalled on most Dell PCs was affected by a DLL hijacking vulnerability that could have been exploited by an attacker with regular user permissions to execute arbitrary code with elevated privileges by planting specially crafted DLL files in specific locations.
SupportAssist is designed to check the health of a system, including software and hardware. These checks require elevated privileges so many of the associated services run with SYSTEM permissions.
“The vulnerability gives attackers the ability to load and execute malicious payloads by a signed service. This ability might be abused by an attacker for different purposes such as execution and evasion, for example: Application Whitelisting Bypass, Signature Validation Bypassing,” SafeBreach said in a blog post.
SafeBreach reported its findings to Dell in late April. Dell confirmed the vulnerability, which it tracks as CVE-2019-12280, roughly one week later, but pointed out that it was not specific to its software and instead exists in a SupportAssist component provided by PC-Doctor.
Dell patched the vulnerability in late May with the release of SupportAssist for Business 2.0.1 and SupportAssist for Home PCs 3.2.2. The company said a vast majority of its users received the updates automatically; SupportAssist has automatic updates enabled by default.
On its website, PC-Doctor says its PC-Doctor for Windows tool is preloaded on over 100 million computers worldwide. According to SafeBreach, the vulnerable component is also present in CORSAIR Diagnostics, Staples EasyTech Diagnostics, and Tobii I-Series and Tobii Dynavox diagnostic tools. PC-Doctor has yet to publish an advisory for this flaw.
This is not the first time a researcher has found a vulnerability in Dell SupportAssist caused by a PC-Doctor driver. A researcher last year disclosed another privilege escalation flaw caused by PC-Doctor software.
In late April, an expert reported identifying a SupportAssist weaknesses that could have been used for code execution.