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.
Adversaries may also exploit edge network infrastructure and related appliances, specifically targeting devices that do not support robust host-based defenses.
For websites and databases, the OWASP top 10 and CWE top 25 highlight the most common web-based vulnerabilities.
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.
APT29 has exploited CVE-2019-19781 for Citrix, CVE-2019-11510 for Pulse Secure VPNs, CVE-2018-13379 for FortiGate VPNs, and CVE-2019-9670 in Zimbra software to gain access.
APT41 exploited CVE-2020-10189 against Zoho ManageEngine Desktop Central, and CVE-2019-19781 to compromise Citrix Application Delivery Controllers (ADC) and gateway devices.
Axiom has been observed using SQL injection to gain access to systems.
BackdoorDiplomacy has exploited CVE-2020-5902, an F5 BIP-IP vulnerability, to drop a Linux backdoor. BackdoorDiplomacy has also exploited mis-configured Plesk servers.
BlackTech has exploited a buffer overflow vulnerability in Microsoft Internet Information Services (IIS) 6.0, CVE-2017-7269, in order to establish a new HTTP or command and control (C2) server.
Blue Mockingbird has gained initial access by exploiting CVE-2019-18935, a vulnerability within Telerik UI for ASP.NET AJAX.
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.
Dragonfly has conducted SQL injection attacks, exploited vulnerabilities CVE-2019-19781 and CVE-2020-0688 for Citrix and MS Exchange, and CVE-2018-13379 for Fortinet VPNs.
Earth Lusca has compromised victims by directly exploiting vulnerabilities of public-facing servers, including those associated with Microsoft Exchange and Oracle GlassFish.
Fox Kitten has exploited known vulnerabilities in Fortinet, PulseSecure, and Palo Alto VPN appliances.
GALLIUM exploited a publicly-facing servers including Wildfly/JBoss servers to gain access to the network.
GOLD SOUTHFIELD has exploited Oracle WebLogic vulnerabilities for initial compromise.
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.
Ke3chang has compromised networks by exploiting Internet-facing applications, including vulnerable Microsoft Exchange and SharePoint servers.
Kimsuky has exploited various vulnerabilities for initial access, including Microsoft Exchange vulnerability CVE-2020-0688.
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).
menuPass has leveraged vulnerabilities in Pulse Secure VPNs to hijack sessions.
Moses Staff has exploited known vulnerabilities in public-facing infrastructure such as Microsoft Exchange Servers.
MuddyWater has exploited the Microsoft Exchange memory corruption vulnerability (CVE-2020-0688).
During Night Dragon, threat actors used SQL injection exploits against extranet web servers to gain access.
During Operation CuckooBees, the threat actors exploited multiple vulnerabilities in externally facing servers.
During Operation Wocao, threat actors gained initial access by exploiting vulnerabilities in JBoss webservers.
Rocke exploited Apache Struts, Oracle WebLogic (CVE-2017-10271), and Adobe ColdFusion (CVE-2017-3066) vulnerabilities to deliver malware.
Siloscape is executed after the attacker gains initial access to a Windows container using a known vulnerability.
During the SolarWinds Compromise, APT29 exploited CVE-2020-0688 against the Microsoft Exchange Control Panel to regain access to a network.
SoreFang can gain access by exploiting a Sangfor SSL VPN vulnerability that allows for the placement and delivery of malicious update binaries.
sqlmap can be used to automate exploitation of SQL injection vulnerabilities.
Threat Group-3390 has exploited the Microsoft SharePoint vulnerability CVE-2019-0604 and CVE-2021-26855, CVE-2021-26857, CVE-2021-26858, and CVE-2021-27065 in Exchange Server.
Volatile Cedar has targeted publicly facing web servers, with both automatic and manual vulnerability discovery. 
ZxShell has been dropped through exploitation of CVE-2011-2462, CVE-2013-3163, and CVE-2014-0322.
|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.