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.(Citation: NVD CVE-2016-6662)(Citation: CIS Multiple SMB Vulnerabilities)(Citation: US-CERT TA18-106A Network Infrastructure Devices 2018)(Citation: Cisco Blog Legacy Device Attacks)(Citation: NVD CVE-2014-7169) Depending on the flaw being exploited this may also involve [Exploitation for Defense Evasion](https://attack.mitre.org/techniques/T1211) or [Exploitation for Client Execution](https://attack.mitre.org/techniques/T1203).

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](https://attack.mitre.org/techniques/T1611), 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.(Citation: Mandiant Fortinet Zero Day)(Citation: Wired Russia Cyberwar)

For websites and databases, the OWASP top 10 and CWE top 25 highlight the most common web-based vulnerabilities.(Citation: OWASP Top 10)(Citation: CWE top 25)
Exploit Public-Facing Application
source_name: mitre-attack  url: https://attack.mitre.org/techniques/T1190  external_id: T1190     source_name: CWE top 25  description: Christey, S., Brown, M., Kirby, D., Martin, B., Paller, A.. (2011, September 13). 2011 CWE/SANS Top 25 Most Dangerous Software Errors. Retrieved April 10, 2019.  url: https://cwe.mitre.org/top25/index.html     source_name: CIS Multiple SMB Vulnerabilities  description: CIS. (2017, May 15). Multiple Vulnerabilities in Microsoft Windows SMB Server Could Allow for Remote Code Execution. Retrieved April 3, 2018.  url: https://www.cisecurity.org/advisory/multiple-vulnerabilities-in-microsoft-windows-smb-server-could-allow-for-remote-code-execution/     source_name: Wired Russia Cyberwar  description: Greenberg, A. (2022, November 10). Russia’s New Cyberwarfare in Ukraine Is Fast, Dirty, and Relentless. Retrieved March 22, 2023.  url: https://www.wired.com/story/russia-ukraine-cyberattacks-mandiant/     source_name: Mandiant Fortinet Zero Day  description: Marvi, A. et al.. (2023, March 16). Fortinet Zero-Day and Custom Malware Used by Suspected Chinese Actor in Espionage Operation. Retrieved March 22, 2023.  url: https://www.mandiant.com/resources/blog/fortinet-malware-ecosystem     source_name: NVD CVE-2016-6662  description: National Vulnerability Database. (2017, February 2). CVE-2016-6662 Detail. Retrieved April 3, 2018.  url: https://nvd.nist.gov/vuln/detail/CVE-2016-6662     source_name: NVD CVE-2014-7169  description: National Vulnerability Database. (2017, September 24). CVE-2014-7169 Detail. Retrieved April 3, 2018.  url: https://nvd.nist.gov/vuln/detail/CVE-2014-7169     source_name: Cisco Blog Legacy Device Attacks  description: Omar Santos. (2020, October 19). Attackers Continue to Target Legacy Devices. Retrieved October 20, 2020.  url: https://community.cisco.com/t5/security-blogs/attackers-continue-to-target-legacy-devices/ba-p/4169954     source_name: OWASP Top 10  description: OWASP. (2018, February 23). OWASP Top Ten Project. Retrieved April 3, 2018.  url: https://www.owasp.org/index.php/Category:OWASP_Top_Ten_Project     source_name: US-CERT TA18-106A Network Infrastructure Devices 2018  description: US-CERT. (2018, April 20). Russian State-Sponsored Cyber Actors Targeting Network Infrastructure Devices. Retrieved October 19, 2020.  url: https://us-cert.cisa.gov/ncas/alerts/TA18-106A     