Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network. The weakness in the system can be a software bug, a temporary glitch, or a misconfiguration.
Exploited applications are often websites/web servers, but can also include databases (like SQL), standard services (like SMB or SSH), network device administration and management protocols (like SNMP and Smart Install), and any other system with Internet accessible open sockets. Depending on the flaw being exploited this may also involve Exploitation for Defense Evasion.
If an application is hosted on cloud-based infrastructure and/or is containerized, then exploiting it may lead to compromise of the underlying instance or container. This can allow an adversary a path to access the cloud or container APIs, exploit container host access via Escape to Host, or take advantage of weak identity and access management policies.
APT28 has used a variety of public exploits, including CVE 2020-0688 and CVE 2020-17144, to gain execution on vulnerable Microsoft Exchange; they have also conducted SQL injection attacks against external websites.
During C0017, APT41 exploited CVE-2021-44207 in the USAHerds application and CVE-2021-44228 in Log4j, as well as other .NET deserialization, SQL injection, and directory traversal vulnerabilities to gain initial access.
During C0018, the threat actors exploited VMWare Horizon Unified Access Gateways that were vulnerable to several Log4Shell vulnerabilities, including CVE-2021-44228, CVE-2021-45046, CVE-2021-45105, and CVE-2021-44832.
HAFNIUM has exploited CVE-2021-26855, CVE-2021-26857, CVE-2021-26858, and CVE-2021-27065 to compromise on-premises versions of Microsoft Exchange Server, enabling access to email accounts and installation of additional malware.
Magic Hound has exploited the Log4j utility (CVE-2021-44228), on-premises MS Exchange servers via "ProxyShell" (CVE-2021-34473, CVE-2021-34523, CVE-2021-31207), and Fortios SSL VPNs (CVE-2018-13379).
|M1048||Application Isolation and Sandboxing||
Application isolation will limit what other processes and system features the exploited target can access.
Web Application Firewalls may be used to limit exposure of applications to prevent exploit traffic from reaching the application.
Segment externally facing servers and services from the rest of the network with a DMZ or on separate hosting infrastructure.
|M1026||Privileged Account Management||
Use least privilege for service accounts will limit what permissions the exploited process gets on the rest of the system.
Update software regularly by employing patch management for externally exposed applications.
Regularly scan externally facing systems for vulnerabilities and establish procedures to rapidly patch systems when critical vulnerabilities are discovered through scanning and through public disclosure.
|ID||Data Source||Data Component||Detects|
|DS0015||Application Log||Application Log Content||
Detecting software exploitation may be difficult depending on the tools available. Software exploits may not always succeed or may cause the exploited process to become unstable or crash. Web Application Firewalls may detect improper inputs attempting exploitation.
|DS0029||Network Traffic||Network Traffic Content||
Use deep packet inspection to look for artifacts of common exploit traffic, such as SQL injection strings or known payloads.