Kimsuky APT exploited BlueKeep RDP flaw in attacks against South Korea and Japan
Vulnerabilities mentionedAll →
| CVE | Vulnerability | CVSS | EPSS | Flags | Affected | Exposure | Published |
|---|---|---|---|---|---|---|---|
| CVE-2017-11882 | Memory Corruption RCE in Microsoft Office via Legacy Equation Editor CVE-2017-11882 is a memory corruption vulnerability (CWE-119) in Microsoft Office, residing in the legacy Microsoft Equation Editor component (EQNEDT32.EXE), that allows remote code execution in the context of the current user. Attackers trigger it by persuading a user to open a crafted document, most commonly an RTF file or other Office document carrying a malicious embedded equation object, which overflows a buffer while the equation content is parsed. Successful exploitation lets the attacker run arbitrary code with the privileges of the signed-in user, a typical foothold for malware delivery and, per CISA, for ransomware operations. Any environment running affected Microsoft Office builds is exposed; the source data does not enumerate specific affected version ranges. The flaw is confirmed exploited in the wild: it was added to the CISA Known Exploited Vulnerabilities catalog on 2021-11-03 with known ransomware use and holds a 99.9% EPSS score (percentile 100), though the source data lists no public PoC. Do: Apply Microsoft's Office security updates (November 2017 or later) across all endpoints, prioritizing this KEV-listed flaw given its known ransomware use. On systems that cannot yet be patched, disable or unregister the legacy Equation Editor (EQNEDT32.EXE) and consider blocking or warning on RTF attachments as interim mitigations. Check for indicators of abuse such as EQNEDT32.EXE spawning unexpected child processes after document opens. | 7.8 | 100% | KEV ransomware PoC ×10 |
| masshundreds of millions of users/installations (Office is near-ubiquitous on Windows and in enterprises; the share still unpatched is unknown) | |
| CVE-2019-0708 | Unauthenticated RCE in Microsoft Remote Desktop Services (BlueKeep) CVE-2019-0708 is a use-after-free (CWE-416) vulnerability in Microsoft Remote Desktop Services, formerly Terminal Services, in which an unauthenticated attacker can connect to a target system over RDP and send specially crafted requests to trigger the flaw. Because the trigger requires no authentication, the flaw is wormable: a successful exploit grants remote code execution on the target host, potentially with elevated privileges, and could allow self-propagating attacks similar to WannaCry. Organizations running the affected Microsoft Remote Desktop Services, particularly legacy Windows releases still accepting inbound RDP connections, are in scope. Exploitation is confirmed in the wild: the flaw (nicknamed BlueKeep) is listed in CISA's KEV catalog (added 2021-11-03), CISA notes known ransomware use, and EPSS assigns it a 100% probability of exploitation within 30 days. Do: Apply Microsoft's security updates for CVE-2019-0708 per vendor instructions, prioritizing legacy or end-of-support Windows systems exposed to inbound RDP. As mitigation, restrict RDP (TCP 3389) to trusted networks or VPN access, require Network Level Authentication (NLA), and audit perimeter firewalls and public scans for open RDP listeners. The vulnerability is in the CISA KEV catalog, so patching is treated as a required action for federal and high-risk environments. | 9.8 | 100% | KEV ransomware PoC ×4 |
| masson the order of millions of internet-exposed RDP endpoints and far more internal systems |
Full article459 words · extracted from securityaffairs.com · click to collapse
Researchers spotted a new North Korea-linked group Kimsuky ‘s campaign, exploiting a patched Microsoft Remote Desktop Services flaw to gain initial access.
While investigating a security breach, the AhnLab SEcurity intelligence Center (ASEC) researchers discovered a North Korea-linked group Kimsuky ‘s campaign, tracked as Larva-24005. Attackers exploited an RDP vulnerability to gain initial access to the target systems.
“In some systems, initial access was gained through exploiting the RDP vulnerability (BlueKeep, CVE-2019-0708). While an RDP vulnerability scanner was found in the compromised system, there is no evidence of its actual use.” reads the report published by ASEC. “The threat actor also used other means to distribute the malware, such as attaching the same file to emails and exploiting the Microsoft Office Equation Editor vulnerability (CVE-2017-11882)[1].”
Once they gained access to the systems, the threat actors modified the configuration by installing MySpy malware and RDPWrap to maintain remote access.
In the final stage, the attackers deployed KimaLogger or RandomQuery keyloggers to record keystrokes. Experts observed Kimsuky sending phishing emails targeting Korea and Japan from compromised systems.
Since September 2023, the North Korean APT has targeted organizations in South Korea, the U.S., China, Japan, Germany, Singapore, and several other countries. Their activity includes phishing campaigns against South Korea and Japan and attacks on South Korea’s software, energy, and financial sectors starting in October 2023.
ASEC researchers also published indicators of compromise (IoC) for this campaign.
Kimsuky cyberespionage group (aka ARCHIPELAGO, Black Banshee, Thallium, Velvet Chollima, APT43) was first spotted by Kaspersky researchers in 2013. The group works under the control of the Reconnaissance General Bureau (RGB) foreign intelligence service. At the end of October 2020, the US-CERT published a report on Kimusky’s recent activities that provided information on their TTPs and infrastructure.
The APT group mainly targets think tanks and organizations in South Korea, other victims were in the United States, Europe, and Russia.
In February, ASEC researchers observed North Korea’s Kimsuky APT group conducting spear-phishing attacks to deliver forceCopy info-stealer malware.
The state-sponsored hackers sent spear-phishing messages to distribute malicious *.LNK shortcut files, disguised as Office documents. When opened, they execute PowerShell or Mshta to download malware like PebbleDash and RDP Wrapper, to control the infected systems.
The attackers use a custom-built RDP Wrapper to enable remote desktop access, likely modifying export functions to evade detection.
The researchers noticed that the threat actors also install proxy malware to achieve external access to the infected systems that are located in a private network.
The Kimsuky group uses keyloggers in multiple file formats, including a PowerShell script.
Kimsuky also used the forceCopy stealer malware to capture keystrokes and extract files from browser directories.
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