The NCSC said it was issuing the caution after verifying several sources. It said the Windows flaw was more serious than previously announced.
The flaw or vulnerability, codenamed CVE-2021-1675, exists in the Windows Print Spooler feature. The center said this was a type of vulnerability that allows a "privilege escalation attack" wherein the attackers can turn a regular account into a higher level of control on the computer. Microsoft has announced that this vulnerability affects most versions of Windows, including Windows 10/8.1/7, Windows Server 2019/2016/2012/2008.
On the hazard scale, CVE-2021-1675 is rated 7.8/10.
This vulnerability was patched by Microsoft on June 8. However, according to the Ministry of Information and Communications, this vulnerability is more serious than the published figures. Malicious people can exploit the vulnerability in a number of ways, including direct attacks on Windows computers or servers; or attacks through a computer in the network.
"CVE-2021-1675 can be fully utilized to conduct large-scale advanced persistent threat (APT) attack campaigns in the coming time in Vietnam's cyberspace," an NCSC representative said.
The Ministry of Information and Communications has said that agencies and organizations need to inspect and review their systems to identify potentially affected servers and workstations. It is necessary to update the security patch on servers according to Microsoft's instructions and have a plan to intervene on detecting signs of attack, the ministry said.
APT is a dangerous form of attack. After identifying a specific target, hackers will use advanced techniques to launch attacks that can be sustained for a long time, until they achieve their purpose or are prevented.
According to a report prepared by cybersecurity corporation Bkav, Vietnam lost about $1 billion in 2020 because of computer viruses. In particular, APT attacks caused great damage with a stealth malware named W32.Fileless, the report said.