By Yang Tianzi
On Jan. 20, South Korean media cited judicial sources reporting that last month the Supreme Court of South Korea issued a final ruling in a major military intelligence leak case that shocked the nation. Cheon [surname], a 51-year-old officer of the Republic of Korea (ROK) Military Intelligence Command, was sentenced to 20 years in prison, fined 1 billion KRW, and ordered to forfeit 162.05 million KRW in criminal proceeds for allegedly violating the “general enemy-assisting” provisions of the Military Criminal Act. This case not only exposed serious security vulnerabilities within South Korea’s military intelligence system, but also highlighted the stark reality of systematic Chinese Communist Party (CCP) intelligence infiltration into South Korea, sparking deep public concern over national security.
Major national security loopholes exposed
According to detailed reports from Yonhap News Agency and the Chosun Ilbo, Cheon was not an ordinary officer but a senior officer holding a key position within the ROK Military Intelligence Command. As one of the military’s core intelligence agencies, the command is primarily responsible for collecting and analyzing military intelligence on North Korea and neighboring countries, with its personnel having access to highly sensitive information critical to national security.
Cheon’s path to betrayal began in April 2017. During a visit to China, he was approached and allegedly recruited by an individual “B,” suspected of being affiliated with Chinese intelligence. What appeared to be a routine visit became the turning point that led Cheon down the path of treason. After nearly two years of planning and preparation, beginning in 2019, Cheon began formally leaking a large amount of South Korean military secrets to Chinese intelligence, a betrayal that continued for several years.
Notably, from June 2022 to 2024, Cheon was promoted to head of an intelligence workgroup—a critical position granting him access to South Korea’s most core and sensitive military intelligence. Exploiting this unique position, he leaked a total of 30 highly sensitive pieces of intelligence to Chinese agencies, including 12 classified documents and 18 voice-recorded items.
Staggering leaks endanger colleagues
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Among the leaked materials, the most destructive was the disclosure of the “black personnel” list. “Black personnel” refers to covert operatives or spies who carry out secret missions, often in hostile territories or overseas. Their identities must remain strictly confidential for survival and mission success. Exposure not only compromises missions but also endangers lives.
In addition to the “black personnel” list, Cheon leaked information on the organizational structure of the Military Intelligence Command, operational plans targeting specific regions and objectives, and intelligence exchange and command system details between units. If this information fell into CCP hands, it could severely undermine South Korea’s intelligence gathering, counterintelligence, and military deployments, while directly threatening the lives of frontline intelligence personnel and their collaborators.
Investigations revealed that Cheon’s leaks were motivated not by ideology or politics but by money. In the process of providing classified intelligence to Chinese agents, Cheon requested payment 40 times, demonstrating significant initiative and greed. The total amount promised by the Chinese side was 400 million KRW, and Cheon actually received 162.05 million KRW through proxy accounts.
This clear pattern of trading state secrets for personal gain demonstrates that Cheon’s motives were driven by material desire. He was not passively accepting offered rewards but actively and repeatedly demanding money, a direct violation of military professionalism and patriotic duty.
Judicial proceedings: all three courts uphold severe sentence
The case underwent the full South Korean judicial process. The first-instance court, after thorough examination, determined that Cheon’s actions constituted serious enemy-assisting crimes, sentencing him to 20 years in prison, a 1.2 billion KRW fine, and confiscation of 162.05 million KRW in criminal proceeds. The appellate court maintained the 20-year prison term and confiscation of criminal proceeds but reduced the fine to 1 billion KRW, still reflecting severe condemnation of the crime.
The original trial judge emphasized the severity and egregious nature of Cheon’s actions, stating: “The defendant has served long in the Intelligence Command and knew better than anyone the serious consequences of leaking personal intelligence. He fully understood that it would pose a major threat to the lives of relevant personnel. This is tantamount to selling out colleagues’ lives.”
The judge further noted that even if the exposed operatives returned safely to South Korea, their identities being compromised would make their future safety uncertain. These personnel could face long-term security threats, and their careers might be ended. The court stated clearly: “No matter the defense, the crime is extremely egregious and cannot be justified. The defendant cannot escape severe punishment.”
Defendant’s defense rejected
During the trial, Cheon claimed that during his April 2017 visit to China, he was “kidnapped” by B and threatened that if he did not comply, his family would be harmed. He argued his leaks were coerced and unavoidable.
However, the court found no objective evidence to support his claims of kidnapping or threats, beyond Cheon’s own statements. More importantly, Cheon’s behavior during the crime was inconsistent with a coerced victim. Evidence showed he actively negotiated and requested payment from B, demonstrating initiative and transactional intent incompatible with “acting under threat.” Even assuming some initial pressure, his long-term, repeated, and voluntary leaks clearly reflected personal malice and selfish motives.
Supreme Court final ruling upholds heavy sentence, reflecting judicial stance
Cheon appealed the appellate court decision to the Supreme Court, which ultimately rejected his appeal. In its final review, the court considered factors including age, character, living environment, motive, method, outcomes, and post-crime attitude, finding no serious error in the lower court rulings.
The final judgment not only served as ultimate punishment for Cheon’s crimes but also expressed South Korea’s firm position against leaking state secrets and endangering national security. A 20-year sentence is considered severe under South Korean law, demonstrating zero tolerance and sending a strong warning to society.
Deep background of CCP infiltration in South Korea
The Cheon case is only the tip of the iceberg regarding systematic CCP intelligence penetration into South Korea. In recent years, amid U.S.-China strategic competition and shifts in Indo-Pacific geopolitics, South Korea’s strategic location has made it a focal point for intelligence activity.
Geopolitically, South Korea is a key U.S. ally in East Asia, hosts a large U.S. military presence, and controls critical intelligence on the Korean Peninsula. It shares land or maritime borders with both China and North Korea, placing it at a strategic crossroads in Northeast Asia. These factors make South Korea a prime target for CCP intelligence seeking military, diplomatic, and North Korea-related information.
The CCP uses diverse, systematic methods of infiltration, including traditional human intelligence, academic exchanges, business cooperation, cultural activities, and other seemingly normal channels. Chinese intelligence also leverages close economic ties with South Korea to seek opportunities for intelligence collection. Many South Korean businessmen and scholars visiting China may unknowingly become intelligence targets.
Additionally, the CCP increasingly uses cyber techniques to infiltrate South Korea. The country has faced multiple suspected cyberattacks originating from China targeting government agencies, military systems, and major corporations. These attacks not only steal sensitive information but can plant backdoors for long-term intelligence gathering.
In response, South Korean authorities have strengthened counterintelligence, implementing stricter security vetting, especially for personnel with access to sensitive information. Intelligence cooperation with allies such as the U.S. has been enhanced, and cybersecurity defenses have been fortified to prevent external intrusion and intelligence theft.
Nevertheless, South Korea faces real challenges in countering CCP infiltration. The close economic ties with China, its largest trading partner, require careful balancing in security decisions. Additionally, domestic debate over China policy complicates the implementation of unified countermeasures.
