The vulnerability accounts for nearly 66% of attacks using Office Word.
APT attacks, targeting Tibetans, Uyghurs, human rights groups in Taiwan and Hong Kong, and journalists.
Vulnerable component: Microsoft Office
CVSSv3 score: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H/E:H/RL:O/RC:C
CWE-ID: CWE-119 - Improper Restriction of Operations within the Bounds of a Memory Buffer
The vulnerability allows a remote attacker to execute arbitrary code on the target system.
The weakness exists due to boundary error when handling rich text format files. A remote attacker can create a specially crafted RTF document, trick the victim into opening it, trigger memory corruption and execute arbitrary code with privileges of the current user.
Successful exploitation results in arbitrary code execution on the vulnerable system.
Note: the vulnerability was being actively exploited.
Known APT campaigns:
China-based group KeyBoy
KeyBoy is a threat actor believed to operate from China.
Firstly its malicious activity has been observed in summer 2016 in attacks targeting Tibetan Community. In the hacking campaigns not only against Tibet, but also Hong Kong, Taiwan, and Uyghur the group has been exploiting vulnerabilities CVE-2012-0158╨▒ CVE-2012-1856, CVE-2015-1641 and CVE-2015-1770.
Researchers for Trend Micro linked KeyBoy to Operation Tropic Trooper, campaign targeting Taiwan and the Philippines since 2012.