In fact, from the attackers’ perspective they were trying to create the reverse of the normal situation – a friendly (to them) guest environment protected from a hostile host. However, the protections that separate the guests from their host assume a hostile guest inside a friendly host, and that wasn’t the case here, because the attackers had access to both guest and host. This is to prevent hostile processes, like malware, from attacking the host or taking it over, in what’s known as a virtual machine escape. Typically, guests are sealed off from the host, and processes running inside the guest are unable to interact with the host’s operating system. VirtualBox is hypervisor software that can run and administer one or more virtual guest computers inside a host computer. SophosLabs reports that in the attack, the gang used a Windows GPO (Group Policy Object) task to execute the Microsoft Installer, which downloaded an MSI containing a number of files, including a copy of VirtualBox and a Windows XP virtual machine with the Ragnar Locker executable inside. Living off the land entails using legitimate software administration tools that either already exist on the network the crooks have broken into, or that don’t look suspicious or out of place ( PowerShell is a particular favourite).
Like a lot criminals who conduct similar “targeted” or “big game” ransomware attacks, the Ragnar Locker gang try to avoid detection as they operate inside a victim’s network with a tactic dubbed “living off the land”. The attack was carried out by the gang behind Ragnar Locker, who break into company networks, make themselves admins, conduct reconnaissance, delete backups and deploy ransomware manually, before demanding multi-million dollar ransoms. To ensure their 49 kB Ragnar Locker ransomware ran undisturbed, the crooks behind the attack bought along a 280 MB Windows XP virtual machine to run it in (and a copy of Oracle VirtualBox to run that).
Yesterday, SophosLabs published details of a sophisticated new ransomware attack that takes the popular tactic of “ living off the land” to a new level.
0 kommentar(er)
