Pro-Russia hackers target inboxes with 0
Vulnerabilities mentionedAll →
| CVE | Vulnerability | CVSS | EPSS | Flags | Affected | Exposure | Published |
|---|---|---|---|---|---|---|---|
| CVE-2023-5631 | Stored XSS in Roundcube Webmail exploited in the wild (CVE-2023-5631) CVE-2023-5631 is a stored cross-site scripting (XSS) flaw in Roundcube Webmail caused by insufficient sanitization of SVG content embedded in HTML email by program/lib/Roundcube/rcube_washtml.php. A remote attacker triggers it by sending a crafted HTML email containing a malicious SVG document; when the recipient views the message, arbitrary JavaScript is loaded in their browser session. This lets the attacker act as the victim within the webmail session — for example reading mail or capturing session data — and it has been used in targeted espionage rather than commodity attacks. Anyone running Roundcube before 1.4.15, 1.5.x before 1.5.5, or 1.6.x before 1.6.4 is affected, including Roundcube packages shipped by Debian and Fedora. Exploitation is confirmed in the wild: the flaw was added to CISA's KEV on 2023-10-26, the Winter Vivern espionage group is reported to have exploited it as a zero-day against government entities, and EPSS puts the 30-day exploitation probability at ~76% (99th percentile). Do: Upgrade to Roundcube 1.6.4, or 1.5.5 on the 1.5.x branch and 1.4.15 on the 1.4.x branch; apply the corresponding patched roundcube packages for Debian or Fedora. Per the CISA KEV required action, apply vendor mitigations or discontinue use if patching is unavailable. Hunt for compromise by reviewing webmail logs and stored messages for crafted SVG/HTML emails sent around the exploitation window, and review sessions for signs of hijacking. | 5.4 | 76% | KEV PoC |
| largetens of thousands of internet-exposed Roundcube servers; plausibly 100k+ end users, unknown precisely |
Full article292 words · extracted from arstechnica.com · click to collapse
A relentless team of pro-Russia hackers has been exploiting a zero-day vulnerability in widely used webmail software in attacks targeting governmental entities and a think tank, all in Europe, researchers from security firm ESET said on Wednesday.
The previously unknown vulnerability resulted from a critical cross-site scripting error in Roundcube, a server application used by more than 1,000 webmail services and millions of their end users. Members of a pro-Russia and Belarus hacking group tracked as Winter Vivern used the XSS bug to inject JavaScript into the Roundcube server application. The injection was triggered simply by viewing a malicious email, which caused the server to send emails from selected targets to a server controlled by the threat actor.
No manual interaction required
“In summary, by sending a specially crafted email message, attackers are able to load arbitrary JavaScript code in the context of the Roundcube user’s browser window,” ESET researcher Matthieu Faou wrote. “No manual interaction other than viewing the message in a web browser is required.”
The attacks began on October 11, and ESET detected them a day later. ESET reported the zero-day vulnerability to Roundcube developers on the same day, and they issued a patch on October 14. The vulnerability is tracked as CVE-2023-5631 and affects Roundcube versions 1.6.x before 1.6.4, 1.5.x before 1.5.5, and 1.4.x before 1.4.15.
Winter Vivern has been operating since at least 2020 and targets governments and think tanks, primarily in Europe and Central Asia. In March, the threat group was spotted targeting US government officials who had voiced support for Ukraine in its bid to drive back Russia’s invasion. Those attacks also exfiltrated targets’ emails but exploited a separate, already-patched XSS in Zimbra Collaboration, a software package that’s also used to host webmail portals.
Text extracted automatically; images, tables and formatting may be missing. Original: https://arstechnica.com/security/2023/10/pro-russia-hackers-target-inboxes-with-0-day-in-webmail-app-used-by-millions/