Just a quick post today to discuss three threat scenarios we are modeling frequently with clients these days. #ThreatModeling
1) Ransomeware or other malware infection sourced from managed service providers – this scenario is become a very common issue, so common that DHS and several other organizations have released advisories. Attacker campaigns against managed services providers have been identified and many have yielded some high value breaches. The most common threat is spear phishing into a MSP, with the attackers eventually gaining access to the capability to push software to the clients. They then push a command and control malware or a ransomware infection down the pipe. Often, it is quite some time before the source of the event is traced back to the MSP. The defenses here are somewhat limited, but the scenario definitely should be practiced at the tabletop level. Often, these MSPs have successfully passed a SOC audit, but have very little security maturity beyond the baselines.
2) Successful credential stuffing attacks against Office 365 implementations leading to wire/ACH/AP fraud – This is another very common scenario, not just for banks and credit unions, but a lot of small and mid-size organizations have fallen victim to it as well via account payable attacks. In the scenario, either a user is phished into giving up credentials, or a leaked set of credentials is leveraged to gain access to the Office 365 mail and chat system. The attackers then leverage this capability to perform their fraud, appearing to come from internal email accounts and chats. They often make use of stored forms and phish their way to other internal users in the approval chain to get the money to actually move. Once they have their cash, they often use these email accounts to spread malware and ransomware to other victims inside the organization or in business partners – continuing the chain over and over again. The defenses here are to MFA, limited access to the O365 environment to require VPN or other IP-specifc filtering, hardening the O365 environment and enabling many of the detection and prevention controls that are off by default.
3) Voicemail hacking and dial-system fraud – I know, I know, it’s 2020… But, this remains an incredibly impactful attack, especially against key management employees or employees who traffic in highly confidential data. Often this is accessed and then either used for profit via trading (think M&A info) or as ransom/blackmail types of social engineering. Just like above, the attackers often hack one account and then use social engineering to get other users to follow instructions around fraud or change their voicemail password to a given number, etc. Larger corporations where social familiarity of employees and management is low are a common attack target. Dial system fraud for outbound long distance remains pretty common, especially over long weekends and holidays. Basically, the attackers hack an account and use call forwarding to send calls to a foreign number – then sell access to the hacked voicemail line, changing the destination number for each caller. Outbound dial tone is also highly regarded here and quite valuable on the underground markets. Often the fraud goes undetected for 60-90 days until the audit process kicks in, leaving the victim several thousand dollars in debt from the illicit activity. The defenses here are voicemail and phone system auditing, configuration reviews, hardening and lowering lockout thresholds on password attempts.
We can help with all of these issues and defenses, but we love to help organizations with threat scenario generation, threat modeling and attack surface mapping. If you need some insights into outside the box attacks and fraud potential, give us a call. Our engagements in this space are informative, useful and affordable.
Thanks for reading, and until next time, stay safe out there!