The most serious flaws appear to be in Lenovo Solution Center and could allow a malicious Web page to execute code on Lenovo Windows-based computers with system privileges.

The flaws were discovered by a hacker who uses the online aliases slipstream and RoL and who released a proof-of-concept exploit for them last week. This prompted the CERT Coordination Center at Carnegie Mellon University to publish a security advisory.

One of the issues is caused by the LSCTaskService, which is created by the Lenovo Solution Center and runs with SYSTEM privileges. This service opens an HTTP daemon on port 55555 that can receive commands. One of those commands is called RunInstaller and executes files placed in the %APPDATA%\LSC\Local Store folder.

Any local user can write to this directory, regardless of their privilege, but the files are executed as the SYSTEM account. This means that a restricted user can exploit the logic flaw to gain full system access.

Furthermore, there is a directory traversal flaw that can be exploited to trick the Lenovo Solution Center to execute code from arbitrary locations, so an attacker doesn’t even need to place files in the aforementioned Local Store folder.

Finally, the LSCTaskService is vulnerable to cross-site request forgery (CSRF), an attack method through which a malicious website can relay rogue requests through the user’s browser. This means that, in order to exploit the previous two flaws, an attacker doesn’t even need to have local access to the system where the Lenovo Solution Center is installed and can simply trick the user to visit a specially crafted Web page.

In a security advisory on its website, Lenovo said that it is currently investigating the vulnerability report and will provide a fix as soon as possible. Until then, concerned users can uninstall the Lenovo Solution Center in order to mitigate the risk, the company said.

Slipstream also published proof-of-concept exploits for two other, lower-impact, vulnerabilities—one in the Toshiba Service Station and one in Dell System Detect (DSD), a tool that users are prompted to install when they click the “Detect Product” button on Dell’s support website.

The Toshiba Service Station application creates a service called TMachInfo that runs as SYSTEM and receives commands via UDP port 1233 on the local host. One of those commands is called Reg.Read and can be used to read most of the Windows registry with system privileges, according to the hacker.

“I have no idea what to do with it, but someone else might,” slipstream wrote in the exploit comments.

The flaw in DSD apparently stems from the way Dell attempted to fix a previous vulnerability. According to slipstream, the company implemented RSA-1024 signatures to authenticate commands, but put them in a place on its website where attackers can obtain them.

These can be used as a crude bypass method for Windows’ User Account Control (UAC). In this context, the bypass means that “if DSD isn’t elevated, we annoy the user with elevation requests until they click yes,” the hacker said.

This is not the first time when vulnerabilities have been found in support tools installed on Lenovo or Dell computers.

Toshiba and Dell did not immediately respond to a request for comment.

source: pcworld