CyberWire Daily - CISA Alert AA23-074A – Threat actors exploit progress telerik vulnerability in U.S. government IIS server. [CISA Cybersecurity Alerts]

Episode Date: March 16, 2023

CISA, FBI, and the Multi-State Information Sharing and Analysis Center are releasing this joint Cybersecurity Advisory to provide IT infrastructure defenders with TTPs, IOCs, and methods to detect and protect against recent exploitation against Microsoft Internet Information Services web servers. AA23-074A Alert, Technical Details, and Mitigations AA23-074A STIX XML MAR-10413062-1.v1 Telerik Vulnerability in U.S. Government IIS Server Telerik: Exploiting .NET JavaScriptSerializer Deserialization (CVE-2019-18935) ACSC Advisory 2020-004 Bishop Fox CVE-2019-18935: Remote Code Execution via Insecure Deserialization in Telerik UI Volexity Threat Research: XE Group GitHub: Proof-of-Concept Exploit for CVE-2019-18935 Microsoft: Configure Logging in IIS GitHub: CVE-2019-18935 No-cost cyber hygiene services: Cyber Hygiene Services and Ransomware Readiness Assessment. See CISA Insights Mitigations and Hardening Guidance for MSPs and Small- and Mid-sized Businesses for guidance on hardening MSP and customer infrastructure. U.S. DIB sector organizations may consider signing up for the NSA Cybersecurity Collaboration Center’s DIB Cybersecurity Service Offerings, including Protective Domain Name System services, vulnerability scanning, and threat intelligence collaboration for eligible organizations. For more information on how to enroll in these services, email [e-mail]  To report incidents and anomalous activity or to request incident response resources or technical assistance related to these threats, contact CISA at [e-mail], or call [phone], or report incidents to your local FBI field office. Learn more about your ad choices. Visit megaphone.fm/adchoices

You're listening to the Cyber Wire Network, powered by N2K. 4 Alpha. Original release date, March 15, 2023. CISA, FBI, and the Multi-State Information Sharing and Analysis Center are releasing this joint cybersecurity advisory to provide IT infrastructure defenders with TTPs, IOCs, and methods to detect and protect against recent exploitation against Microsoft Internet Information Services web servers. From November 2022 through early January 2023, CISA identified IOCs at a federal civilian executive branch agency. Analysts determined that multiple cyber threat actors, including an APT actor and a known cyber criminal group, were able to exploit a.NET deserialization vulnerability located in the agency's

Microsoft Internet Information Services web server. Successful exploitation of this vulnerability allows for remote code execution. When exploiting the vulnerability, the threat actors uploaded malicious DLL files, some masqueraded as ping files, to the temp directory. The malicious files were then executed from the directory via a legitimate process that runs on IIS servers.

The review of antivirus logs identified that some DLL files were created and detected as early as August 2021. FBI and CISA encourage organizations to implement the recommendations in the mitigation section of this alert to reduce the likelihood and impact of similar exploitation. The alert documentation linked in the show notes includes additional technical details, IOCs, malicious actor TTPs, recovery guidance, mitigations, and response recommendations. Google's threat analysis group contributed to this advisory. Threat Analysis Group contributed to this advisory. To report incidents and anomalous activity or to request incident response resources or technical assistance, contact CISA at report at cisa.gov,

call 888-282-0870, or report incidents to your local FBI field office. This report was written by CISA, the United States Cybersecurity and Infrastructure Security Agency, and edited and adapted for audio by the Cyber Wire as a public service. Please visit www.cisa.gov to read the full report, which may include additional details, links, and illustrations. A link to this report can be found in the show notes. This has been a CISA Cybersecurity Alert.