Intel issued a patch on Nov. 10, fixing a vulnerability in the way the Intel Support Assistant interacts with files that could impact millions of Windows systems and could lead to privilege-escalation attacks.
The vulnerability is the latest issue disclosed by access-security firm CyberArk during an 18-month effort to seek out specific types of patterns that could lead to vulnerabilities, analyzing widespread management utilities for flaws that would allow malware or a local attacker to gain system privileges on a victim’s computer. In this case, the Intel Support Assistant interacts insecurely with nonprivileged data and directories, giving attackers the ability to execute code as the privileged program by modifying a nonprivileged file.
The attack only requires a malicious program or user to copy malicious code to a directory used by the utility, according to Eran Shimony, a security researcher with CyberArk. The issues, which allow an attacker to manipulate files, result in raising the permissions of any malware program, giving it the ability to “do a bunch of things that you couldn’t do as a mere user,” the researcher says.
“To trigger the ability is pretty simple: You abuse some of the features of the Intel Support Assistant, and through that, you can escalate into a system account,” he says. “And, if you have local admin, then it is pretty much game over.”
The vulnerabilities underscore the impact that simple errors — such as failing to protect the directories used by system utilities with high-level permissions or running those utilities with reduced access rights — can have on system security. Shimony’s research effort, conducted over 18 months, aimed to provide “a complementary approach to fuzzing” to find new vulnerabilities. By June 2020, the CyberArk research group had discovered more than 60 distinct vulnerabilities.
The research has resulted in a series of security notices from CyberArk and advisories from affected firms about privilege-escalation vulnerabilities in a passel of system utilities — from Microsoft’s Windows Defender to Dell’s Update Package.
Shimony disclosed a vulnerability in Windows Defenders in October 2019, for example, that abused symbolic links, or symlinks — files that link to other files — to allow any file to be deleted on any Windows system without the fix. A few weeks later, the researcher released details of a class of vulnerability caused by the vendors’ failure to protect the directories used by their software installers. An attacker could replace an installed file with malicious code of the same name and then wait for the administrator to run the installer to run the code. Dell’s Update Package, for example, would run whenever there was an update.
The researcher notified Intel of the latest vulnerability more than a year ago. The company needed time to inform all of its partners and work together on a fix, Shimony says. The notification of the Intel Support Assistant vulnerability (CVE-2020-22460) came on Tuesday.
While the vendors have released patches for the vulnerabilities, Shimony urges developers to be aware of this particular class of flaws and has two recommendations for programmers. First, developers should always protect the directories and files used by privileged programs from modification — whether creation, deletion, or manipulation — by regular users. Second, coders should always execute specific operations at the least privilege needed to manipulate local files, by adopting the appropriate role.
“Often, the privileged program can do the same things in the context of the administrator or the system, or it can do the same things in the context of the regular user,” he says. “If the developer can, they should impersonate the local user whenever at all possible. If they do that, we cannot do any file manipulation attack, because we would not have the necessary permissions to do them.”
The researcher also disclosed a second vulnerability in Intel’s Support Assistant that is more complex to exploit and which allows an attacker to delete an arbitrary file.
This is not the first time that the Intel Support Assistant has been a vehicle for privilege escalation. In early September, the company also issued a notice that a similar scenario — a user exploiting file permissions — can lead to escalation of privilege.
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