An Australian security researcher has uncovered a bug that provided him access to an unsecured administration panel for an internal content management system (CMS) used by staff at Yahoo. The issue, which could have reportedly allowed an attacker to gain a foothold into part of the company’s network, has been addressed.
The vulnerability was identified and disclosed to Yahoo by Nathaniel Wakelam, a consultant with RMSEC, a company that provides information security services to clients across Australia and Asia.
According to the expert, who has reported more than 70 vulnerabilities to Yahoo, this was an entirely non-technical bug. He gained access to the administration panel after determining its URL, which he found by thinking logically and by manually going through the stg- and prd- prefix hostnames after seeing which of them were open on ports 80 and 443.
Once he found the URL, Wakelam discovered that he was automatically logged in with full administrative rights without further exploitation being required.
“The web application had originally been designed only to be used by staff internally, but due to a provisioning error the staging server was able to be publicly accessed simply by directly requesting the staging server hostname,” Wakelam told SecurityWeek. “This web application allowed an individual to view, and create organization details, view specific information about sensitive Yahoo service information in the form of manuals, view and search for users, send email using the Yahoo server, and change staff information including emails, and passwords.”
After gaining access to the panel, Wakelam identified multiple post-authentication flaws, which he reported separately to Yahoo. The researcher believes it might have been possible to upload files and execute arbitrary code, but has hasn’t conducted any tests since this was a production server.
Yahoo took the host offline shortly after being notified of the vulnerability through the security response and bug bounty platform HackerOne, the researcher told SecurityWeek.
“This flaw would allow for a malicious third-party to send out spam from a Yahoo server, access sensitive corporate data (names, addresses, and other personal staff information), and allow for the launching of attacks on other Yahoo services. What I’m trying to really communicate though is that not all flaws are high-tech, and even ones that require very little skill to exploit can be devastating,” Wakelam said.
Numerous security holes have been reported to Yahoo over recently. In May, a California-based researcher informed the company that a bug in the Yahoo Toolbar generated a persistent cross-site scripting (XSS) vulnerability in several popular online services.
