Also known as: Codoso Team
Suspected attribution: China
Target sectors: Legal and investment
Overview: A group likely composed of freelancers, with some degree of sponsorship by the Chinese government.
Associated malware: BEACON, COBALTSTRIKE
Attack vectors: In 2017, APT19 used three different techniques to attempt to compromise targets. In early May, the phishing lures leveraged RTF attachments that exploited the Microsoft Windows vulnerability described in CVE 2017-0199. Toward the end of May, APT19 switched to using macro-enabled Microsoft Excel (XLSM) documents. In the most recent versions, APT19 added an application whitelisting bypass to the XLSM documents. At least one observed phishing lure delivered a Cobalt Strike payload.
Further readingFireEye: RTF Attachments
Through the exploitation of the HTA handler vulnerability described in CVE-2017-1099, the observed RTF attachments download hxxp://tk-in-f156.2bunny[.]com/Agreement.doc. Unfortunately, this file was no longer hosted at tk-in-f156.2bunny[.]com for further analysis. Figure 1 is a screenshot of a packet capture showing one of the RTF files reaching out to hxxp://tk-in-f156.2bunny[.]com/Agreement.doc.