North Korea-linked backdoor found compiled inside HAProxy at two South Korean companies

Rapid7 Labs disclosed that DPRK-aligned operators compiled a backdoor named 'ted' directly into the victims' existing HAProxy 2.8.12 load balancers using native HAProxy filter APIs, accompanied by a tool named curlRAT and trojanised crond, agetty, atd, sshd and polkitd daemons. C2 mode was triggered by a request for a decoy image path, after which commands were passed via named pipes and the requests were erased from HAProxy logs and statistics without ever reaching the backend. Two South Korean companies in the automotive and media sectors were confirmed affected, with capabilities including credential harvesting, SSH keylogging, session cookie theft and fingerprint-matched drive-by injection. Attribution to APT37 is medium confidence, with possible Lazarus Group overlap.