Pierluigi Paganini
March 25, 2013
Recently South Korea has been hit by powerful cyber attack malware based, network provided by LG UPlus Corp was hacked by a group calling itself the “Whois Team”. The attack targeted also media and banking of the country, television networks YTN, MBC and KBS and Shinhan Bank and NongHyup Bank, two major banks of the country, suffered serious outage. Fortunately according South Korea’s representative none of critical infrastructures of the country was interested by the attacks.
All principal security firms are investigating on the event analyzing the malicious code used for the attacks that revealed the capability to erase data also on Linux machines. The source code of the Windows malware used by attackers presented an unexpected surprise, it was in fact equipped with a module able to work on Linux systems erasing the disks.
The malware include also a BASH shell script, attempts to erase partitions Unix systems, including Linux and HP-UX.
“The bash script is a wiper designed to work with any Linux distribution, with specific commands for SunOS, AIX, HP-UX distributions. It wipes out the /kernel, /usr, /etc, and /home directories.”
The discovery was announced by Symantec firms that dubbed it Jokra, following an extract from its blog post:
” The dropper for Trojan.Jokra contains a module for wiping remote Linux machines. We do not normally see components that work on multiple operating systems, so it is interesting to discover that the attackers included a component to wipe Linux machines inside a Windows threat.”
The trojan Jokra runs on Windows XP and 7 invoking an open source remote access manager, named mRemote, that could be used to manage devices on different platforms.
The malware is able to overwrite the Master Boot Record of the infected machine making impossible the bootstrapping, according McAfee analysis the agent wiped out the MBR on the hard drives overwriting it with either one of these strings:
Malware analysts at McAfee explained in their post on the topic:
“The attack also overwrote random parts of the file system with the same strings, rendering several files unrecoverable,” “So even if the MBR is recovered, the files on disk will be compromised too.”
“Three wipers are packaged as a position-independent executable (PIE) and a fourth as a dynamic-link library (DLL) injection. There are also some differences in regard to the timing.”
Another interesting behavior observed by researchers is that the malware also try to kill processes related two South Korean antivirus products commercialized by the companies Ahnlab and Hauri.
Avast security firm discovered the alleged source of the attack against Korean banks, it seems started from website of the Korean Software Property Right Council compromised to serve up an iframe that delivered an attack hosted on a third website.
Officials confirmed that the analysis of IP addresses did not reveal the real responsible for the attacks, due this reason Government of Seoul hasn’t speculated about the event, neither it has blamed North Korea, the situation is very complex and cyber attacks observed on this day may have been triggered by independent groups of hackers or by other states interested in exacerbating tensions in the area.
Who is responsible for the attacks?
Pierluigi Paganini
(Security Affairs – Malware)
