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Safety researchers are monitoring what they are saying is the “mass exploitation” of a safety vulnerability that makes it attainable to take full management of servers operating ownCloud, a extensively used open-source filesharing server app.
The vulnerability, which carries the utmost severity score of 10, makes it attainable 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 mentioned, they started observing “mass exploitation” of their honeypot servers, which masqueraded as weak ownCloud servers to trace makes an attempt to use 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 particular endpoint that exposes delicate info, which might be thought-about exploitation,” Glenn Thorpe, senior director of safety analysis & detection engineering at Greynoise, mentioned in an interview on Mastodon. “For the time being, we have seen 13 IPs which are 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 supplies a URL that, when accessed, reveals configuration particulars from the PHP-based surroundings. In final week’s disclosure, ownCloud officers mentioned that in containerized configurations—similar to these utilizing the Docker virtualization software—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 instances wasn’t enough 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 surroundings (phpinfo). This info contains all of the surroundings variables of the webserver. In containerized deployments, these surroundings variables might embrace 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 eradicate the vulnerability. Moreover, phpinfo exposes varied different probably delicate configuration particulars that might be exploited by an attacker to assemble details about the system. Due to this fact, even when ownCloud is just not operating in a containerized surroundings, 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 just lately the vulnerability tracked as CVE-2023-4966 and CitrixBleed—have. Particularly, unbiased researcher Kevin Beaumont has famous 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 suppose anyone else truly checked if the weak characteristic is enabled,” he mentioned in an interview. What’s extra, an ownCloud Net 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 authentic concern. In response to safety group Shadowserver, a current scan revealed greater 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 comply with ownCloud advisory mitigation steps.”
Extra high-severity ownCloud vulnerabilities
Another excuse for concern: ownCloud just lately fastened 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 understood 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 attainable to redirect callbacks to a site managed by the attacker.
To repair the ownCloud vulnerability underneath 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 varied hardenings in future core releases to mitigate related vulnerabilities.We additionally advise to vary the next secrets and techniques:
– ownCloud admin password
– Mail server credentials
– Database credentials
– Object-Retailer/S3 access-key
Whereas there are not any reviews of the opposite two vulnerabilities being actively exploited, customers ought to comply with the directions ownCloud has supplied right here and right here.
In current months, vulnerabilities in file sharing apps similar 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 just lately fastened ownCloud flaws does so at their very own peril.
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