Cybercrime groups have been exploiting vulnerabilities in digital video recorders (DVRs) made by Taiwan-based surveillance solutions provider LILIN to increase the size of their botnets.
Researchers at Chinese cybersecurity firm Qihoo 360 started seeing attacks in late August 2019. The vendor released firmware updates that should patch the exploited flaws on February 14, but the vulnerabilities had a zero-day status until this date.
According to the researchers, LILIN DVRs are vulnerable to attacks due to hardcoded credentials, default credentials, and the presence of command injection flaws. The command injection vulnerabilities affect three parameters: NTPUpdate, FTP and NTP.
Qihoo 360 spotted the Chalubo malware exploiting the NTPUpdate vulnerability in August 2019, then it saw the FBot (Satori) malware exploiting the FTP and NTP flaws on January 11, and finally it noticed Moobot attacks through the FTP vulnerability on January 26.
These pieces of malware, all of which are based on the notorious Mirai and allow cybercriminals to launch distributed denial-of-service (DDoS) attacks, exploited the LILIN zero-day vulnerabilities to spread. In some cases, exploitation involves both the use of hardcoded or default credentials and the command injection vulnerabilities.
LILIN says it has released firmware updates to address the vulnerabilities and it has advised customers to change default usernames and passwords, as well as communication ports.
Organizations concerned that their DVRs may have been targeted can check the indicators of compromise (IoC) made available by Qihoo 360.
It’s unclear how many devices have been compromised, but LILIN has been around for 40 years and its products are used all around the world. Its surveillance devices are also being sold under other brands.
It’s not uncommon for IoT botnets to target video surveillance devices, particularly since many of these products are plagued by serious and easy to exploit vulnerabilities.
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