The supply chain approach taken by Petya requires a well-funded adversary with a high level of investment into attack skills\/capability. Although supply chain attacks are rising, these still represent a small percentage of how attackers get into corporate environments and require a higher degree of sophistication to execute.<\/li>\n<\/ul>\nPetya and Traversal\/Propagation<\/h2>\n Our observation was that Petya spread more by using identity impersonation techniques than through MS17-010 vulnerability exploitation. This is likely because of the emergency patching initiatives organizations followed to deploy MS17-010 in response to the WannaCrypt attacks and associated publicity.<\/p>\n
The Petya attacks also resurfaced a popular misconception about mitigating lateral traversal which comes up frequently in targeted data theft attacks. If a threat actor has acquired the credentials needed for lateral traversal, you can NOT<\/strong><\/span> block the attack by disabling execution methods like PowerShell or WMI<\/em>. This is not a good choke point because legitimate remote management requires at least one process execution method to be enabled.<\/p>\n <\/p>\n
Figure 2:\u00a0How the Petya attack spreads<\/em><\/p>\nYou\u2019ll see in the illustration above that achieving traversal requires three technical phases:<\/p>\n
1st phase: Targeting<\/strong> \u2013 Identify which machines to attack\/spread to next.<\/p>\nPetya\u2019s targeting mechanism was consistent with normal worm behavior. However, Petya did include a unique \u201cinnovation\u201d where it acquired IPs to target from the DHCP subnet configuration from servers and DCs to accelerate its spread.<\/p>\n
2nd phase: Privilege acquisition<\/strong> \u2013 Gain the privileges required to compromise those remote machines.<\/p>\nA unique aspect of Petya is that it used automated credential theft and re-use to spread, in addition to the vulnerability exploitation. As mentioned earlier, most of the propagation in the attacks we investigated was due to the impersonation technique. This resulted in impersonation of the SYSTEM context (computer account) as well as any other accounts that were logged in to those systems (including service accounts, administrators, and standard users).<\/p>\n
3rd phase: Process execution<\/strong> \u2013 Obtain the means to launch the malware on the compromised machine.<\/p>\nThis phase is not an area we recommend focusing defenses on because:<\/p>\n
\nAn attacker (or worm) with legitimate credentials (or impersonated session) can easily use another available process execution method.<\/li>\n Remote management by IT operations requires at least one process execution method to be available.<\/li>\n<\/ol>\nBecause of this, we strongly advise organizations to focus mitigation efforts on the privilege acquisition phase (2)<\/strong> for both rapid destruction and targeted data theft attacks, and not prioritize blocking at the process execution phase (3)<\/strong>.<\/p>\n <\/p>\n
Figure 3:\u00a0Most Petya propagations were due to impersonation (credential theft)<\/em><\/p>\nBecause of the dual channel approach to propagation, even an organization that had reached 97% of their endpoints with MS17-010 patching was infected enterprise-wide by Petya. This shows that mitigating just one vector is not enough.<\/p>\n
The good news here is that any investment made into credential theft defenses (as well as patching and other defenses) will directly benefit your ability to stave off targeted data theft attacks because Petya simply re-used attack methods popularized in those attacks.<\/p>\n
Attack and Recovery Experience: Learnings from Petya<\/h2>\n Many impacted organizations were not prepared for this type of disaster in their disaster recovery plan. The key areas of learnings from real world cases of these attacks are:<\/p>\n
<\/p>\n
Figure 4:<\/em>\u00a0Common learnings from rapid cyberattack recovery<\/em><\/p>\nOffline Recovery Required<\/strong> \u2013 Many organizations affected by Petya found that their backup applications and Operating System (OS) deployment systems were taken out in the attack, significantly delaying their ability to recover business operations. In some cases, IT staff had to resort to printed documentation because the servers housing their recovery process documentation were also down.<\/p>\nCommunications down<\/strong> \u2013 Many organizations also found themselves without standard corporate communications like email. In almost all cases, company communications with employees was reliant on alternate mechanisms like WhatsApp, copy\/pasting broadcast text messages, mobile phones, personal email addresses, and Twitter.<\/p>\nIn several cases, organizations had a fully functioning Office 365 instance (SaaS services were unaffected by this attack), but users couldn\u2019t access Office 365 services because authentication was federated to the on premises Active Directory (AD), which was down.<\/p>\n
More information<\/h2>\n To learn more about rapid cyber attacks and how to protect against them, watch the on-demand webinar: Protect Against Rapid Cyberattacks (Petya, WannaCrypt, and similar)<\/a>.<\/p>\nLook out for the next and final blog post of a 3-part series to learn about Microsoft’s recommendations on mitigating rapid cyberattacks.<\/p>\n","protected":false},"excerpt":{"rendered":"
In the first blog post of this 3-part series, we introduced what rapid cyberattacks are and illustrated how they are different in terms of execution and outcome. Next, we will go into some more details on the Petya (aka NotPetya) attack. How Petya worked The Petya attack chain is well understood, although a few small […]<\/p>\n","protected":false},"author":61,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"ep_exclude_from_search":false,"_classifai_error":"","footnotes":""},"content-type":[3662],"topic":[3684,3688],"products":[],"threat-intelligence":[],"tags":[3896,3822],"coauthors":[1906],"class_list":["post-80063","post","type-post","status-publish","format-standard","hentry","content-type-news","topic-security-operations","topic-threat-trends","tag-credential-theft","tag-microsoft-security-insights"],"yoast_head":"\n
Overview of Petya, a rapid cyberattack | Microsoft Security Blog<\/title>\n \n \n \n \n \n \n \n \n \n \n \n \n \n \n\t \n\t \n\t \n