2019 will be remembered as the year when major security bugs were disclosed in a large number of enterprise VPN servers, such as those sold by Pulse Secure, Palo Alto Networks, Fortinet, and Citrix.
A new report published today reveals that Iran's government-backed hacking units have made a top priority last year to exploit VPN bugs as soon as they became public in order to infiltrate and plant backdoors in companies all over the world.
According to a report from cyber-security firm ClearSky, Iranian hackers have targeted companies "from the IT, Telecommunication, Oil and Gas, Aviation, Government, and Security sectors."
SOME ATTACKS HAPPENED HOURS AFTER PUBLIC DISCLOSURE
The report comes to dispel the notion that Iranian hackers are not sophisticated, and less talented than their Russian, Chinese, or North Korean counterparts.
ClearSky says that "Iranian APT groups have developed good technical offensive capabilities and are able to exploit 1-day vulnerabilities in relatively short periods of time."
In some instances, ClearSky says it observed Iranian groups exploiting VPN flaws within hours after the bugs been publicly disclosed.
*APT stands for advanced persistent threat and is a term often used to describe nation-state hacking units
ClearSky says that in 2019, Iranian groups were quick to weaponize vulnerabilities disclosed in the Pulse Secure "Connect" VPN (CVE-2019-11510), the Fortinet FortiOS VPN (CVE-2018-13379), and Palo Alto Networks "Global Protect" VPN (CVE-2019-1579).
Attacks against these systems began last summer, when details about the bugs were made public, but they've also continued in 2020.
Furthermore, as details about other VPN flaws were made public, Iranian groups also included these exploits in their attacks (namely CVE-2019-19781, a vulnerability disclosed in Citrix "ADC" VPNs).
HACKING CORPORATE TARGETS TO PLANT BACKDOORS
According to the ClearSky report, the purpose of these attacks is to breach enterprise networks, move laterally throughout their internal systems, and plant backdoors to exploit at a later date.
While the first stage (breaching) of their attacks targeted VPNs, the second phase (lateral movement) involved a comprehensive collection of tools and techniques, showing just how advanced these Iranian hacking units have become in recent years.
For example, hackers abused a long-known technique to gain admin rights on Windows systems via the "Sticky Keys" accessibility tool [1, 2, 3, 4].
They also exploited open-sourced hacking tools like JuicyPotato and Invoke the Hash, but they also used legitimate sysadmin software like Putty, Plink, Ngrok, Serveo, or FRP.
Furthermore, in the case where hackers didn't find open source tools or local utilities to help in their attacks, they also had the knowledge to develop custom malware. ClearSky says it found tools like:
• STSRCheck - Self-developed databases and open ports mapping tool.
• POWSSHNET - Self-developed backdoor malware for RDP-over-SSH tunneling.
• Custom VBScripts - Scripts to download TXT files from the command-and-control (C2or C&C) server and unify these files into a portable executable file.
• Socket-based backdoor over cs.exe - An EXE file used to open a socket-based connection to a hardcoded IP address.
• Port.exe - Tool to scan predefined ports for an IP address.