Cisco has released a proper fix for the critical remote code execution vulnerability affecting the WebEx browser extension, but the patch is currently only available for the Chrome version.
Google Project Zero researcher Tavis Ormandy reported a few days ago that Cisco’s WebEx extension for Chrome, which has roughly 20 million active installs, was affected by a serious flaw that could have been exploited to execute arbitrary code simply by getting a user to access a specially crafted website.
The expert disclosed the details of the flaw after Cisco claimed to have patched it, but it later turned out that the initial fix was incomplete. Ormandy warned that the security hole could still be exploited without any user interaction if an attacker could find a cross-site scripting (XSS) vulnerability on *.webex.com domains – which he did find.
Cisco on Thursday released version 1.0.7 of the WebEx extension for Chrome and Ormandy said he had not found a way to defeat the new patch.
According to Cisco, the vulnerability also affects Firefox and Internet Explorer on Windows, but patches have yet to be released for these web browsers.
Google has restored the WebEx extension in its Chrome Web Store, but Mozilla is still blocking it in Firefox. The networking giant said Mac OS X and Linux systems are not impacted.
The vulnerability, tracked as CVE-2017-3823, can be exploited through a “magic string” used to activate the WebEx extension inside the browser. In an advisory describing the security hole, Cisco said the flaw is caused by a design defect in an API response parser.
In addition to the patch for the Chrome extension, Cisco released Snort rules to help organizations detect potential attacks. Other security vendors have also provided information on how their products can block exploitation attempts. For the time being, there is no evidence that the vulnerability has been exploited in the wild.
Related: Cisco Patches Serious Flaws in Collaboration Products
Related: Serious Flaws Found in Cisco WebEx Meetings Server
Related: Cisco Fixes Severe Flaws in WebEx, Small Business Products
Eduard Kovacs (@EduardKovacs) is a contributing editor at SecurityWeek. He worked as a high school IT teacher for two years before starting a career in journalism as Softpedia’s security news reporter. Eduard holds a bachelor’s degree in industrial informatics and a master’s degree in computer techniques applied in electrical engineering.
More from Eduard Kovacs
- British Retailer JD Sports Discloses Data Breach Affecting 10 Million Customers
- Meta Awards $27,000 Bounty for 2FA Bypass Vulnerability
- Industry Reactions to Hive Ransomware Takedown: Feedback Friday
- US Reiterates $10 Million Reward Offer After Disruption of Hive Ransomware
- Hive Ransomware Operation Shut Down by Law Enforcement
- UK Gov Warns of Phishing Attacks Launched by Iranian, Russian Cyberspies
- Dozens of Cybersecurity Companies Announced Layoffs in Past Year
- Security Update for Chrome 109 Patches 6 Vulnerabilities
Latest News
- Russian Millionaire on Trial in Hack, Insider Trade Scheme
- British Retailer JD Sports Discloses Data Breach Affecting 10 Million Customers
- Vulnerabilities in OpenEMR Healthcare Software Expose Patient Data
- Russia-Linked APT29 Uses New Malware in Embassy Attacks
- Meta Awards $27,000 Bounty for 2FA Bypass Vulnerability
- The Effect of Cybersecurity Layoffs on Cybersecurity Recruitment
- Critical Vulnerability Impacts Over 120 Lexmark Printers
- BIND Updates Patch High-Severity, Remotely Exploitable DoS Flaws
