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Safety researchers are monitoring what they are saying is the “mass exploitation” of a safety vulnerability that makes it potential to take full management of servers operating ownCloud, a broadly used open-source filesharing server app.
The vulnerability, which carries the utmost severity score of 10, makes it potential to acquire passwords and cryptographic keys permitting administrative management of a weak server by sending a easy Net request to a static URL, ownCloud officers warned final week. Inside 4 days of the November 21 disclosure, researchers at safety agency Greynoise said, they started observing “mass exploitation” of their honeypot servers, which masqueraded as weak ownCloud servers to trace makes an attempt to take advantage of the vulnerability. The variety of IP addresses sending the online requests has slowly risen since then. On the time this submit went dwell on Ars, it had reached 13.
Spraying the Web
“We’re seeing hits to the precise endpoint that exposes delicate info, which might be thought-about exploitation,” Glenn Thorpe, senior director of safety analysis & detection engineering at Greynoise, said in an interview on Mastodon. “For the time being, we have seen 13 IPs which can be hitting our unadvertised sensors, which signifies that they’re just about spraying it throughout the web to see what hits.”
CVE-2023-49103 resides in variations 0.2.0 and 0.3.0 of graphapi, an app that runs in some ownCloud deployments, relying on the best way they’re configured. A 3rd-party code library utilized by the app gives a URL that, when accessed, reveals configuration particulars from the PHP-based setting. In final week’s disclosure, ownCloud officers mentioned that in containerized configurations—corresponding to these utilizing the Docker virtualization instrument—the URL can reveal knowledge used to log into the weak server. The officers went on to warn that merely disabling the app in such circumstances wasn’t ample to lock down a weak server.
The ownCloud advisory defined:
The “graphapi” app depends on a third-party library that gives a URL. When this URL is accessed, it reveals the configuration particulars of the PHP setting (phpinfo). This info contains all of the setting variables of the webserver. In containerized deployments, these setting variables might embody delicate knowledge such because the ownCloud admin password, mail server credentials, and license key.
It’s vital to emphasise that merely disabling the graphapi app doesn’t get rid of the vulnerability. Moreover, phpinfo exposes numerous different probably delicate configuration particulars that may very well be exploited by an attacker to assemble details about the system. Subsequently, even when ownCloud will not be operating in a containerized setting, this vulnerability ought to nonetheless be a trigger for concern.
Not all safety practitioners regard the vulnerability as posing a widespread risk, the best way different vulnerabilities—most not too long ago the vulnerability tracked as CVE-2023-4966 and CitrixBleed—have. Particularly, impartial researcher Kevin Beaumont has noted that the CVE-2023-49103 vulnerability wasn’t launched till 2020, isn’t exploitable by default, and was solely launched in containers in February.
“I don’t assume anyone else really checked if the weak function is enabled,” he mentioned in an interview. What’s extra, an ownCloud Web page confirmed graphapi had fewer than 900 installs on the time this submit went dwell on Ars. ownCloud officers didn’t instantly reply to an e-mail in search of technical particulars of the vulnerability and the exact situations required for it to be exploited.
Given the potential risk posed by CVE-2023-49103, there’s nonetheless room for reputable concern. In accordance with safety group Shadowserver, a latest scan revealed more than 11,000 IP addresses internet hosting ownCloud servers, led by addresses in Germany, the US, France, Russia, and Poland. Even when solely a small fraction of the servers are weak, the potential for hurt is actual.
“Not surprisingly given ease of exploitation we now have began seeing OwnCloud CVE-2023-49103 makes an attempt,” Shadowserver officers wrote. “It is a CVSS 10 disclosure of delicate credentials & configs in containerized deployments. Please observe ownCloud advisory mitigation steps.”
Extra high-severity ownCloud vulnerabilities
One more reason for concern: ownCloud not too long ago mounted two different high-severity vulnerabilities, together with CVE-2023-94105, which has a severity score of 9.8. The flaw permits for an authentication bypass within the WebDAV API utilizing pre-signed URLs. Hackers can exploit it “to entry, modify or delete any file with out authentication if the username of the sufferer is thought and the sufferer has no signing-key configured (which is the default),” ownCloud officers warned. The vulnerability impacts the WebDAV API in ownCloud variations 10.6.0 to 10.13.0.
A 3rd vulnerability tracked as CVE-2023-94104 is a subdomain validation bypass flaw with a severity score of 8.7. Hackers can exploit it utilizing a redirect URL, making it potential to redirect callbacks to a website managed by the attacker.
To repair the ownCloud vulnerability below exploitation, ownCloud suggested customers to:
Delete the file
owncloud/apps/graphapi/vendor/microsoft/microsoft-graph/assessments/GetPhpInfo.php.Moreover, we disabled the phpinfo perform in our docker-containers. We’ll apply numerous hardenings in future core releases to mitigate related vulnerabilities.We additionally advise to alter the next secrets and techniques:
– ownCloud admin password
– Mail server credentials
– Database credentials
– Object-Retailer/S3 access-key
Whereas there are not any experiences of the opposite two vulnerabilities being actively exploited, customers ought to observe the directions ownCloud has supplied here and here.
In latest months, vulnerabilities in file sharing apps corresponding to WS-FTP server, MOVEit, and IBM Aspera Faspex, and GoAnywhere MFT have enabled the compromise of 1000’s of enterprise networks. Anybody who ignores the risk posed by the not too long ago mounted ownCloud flaws does so at their very own peril.
