Exploitation of Remote Services
Adversaries may exploit remote services to gain unauthorized access to internal systems once inside of a network. Exploitation of a software vulnerability occurs when an adversary takes advantage of a programming error in a program, service, or within the operating system software or kernel itself to execute adversary-controlled code. A common goal for post-compromise exploitation of remote services is for lateral movement to enable access to a remote system.
An adversary may need to determine if the remote system is in a vulnerable state, which may be done through Network Service Scanning or other Discovery methods looking for common, vulnerable software that may be deployed in the network, the lack of certain patches that may indicate vulnerabilities, or security software that may be used to detect or contain remote exploitation. Servers are likely a high value target for lateral movement exploitation, but endpoint systems may also be at risk if they provide an advantage or access to additional resources.
There are several well-known vulnerabilities that exist in common services such as SMB  and RDP  as well as applications that may be used within internal networks such as MySQL  and web server services. 
Depending on the permissions level of the vulnerable remote service an adversary may achieve Exploitation for Privilege Escalation as a result of lateral movement exploitation as well.
|Application Isolation and Sandboxing||
Make it difficult for adversaries to advance their operation through exploitation of undiscovered or unpatched vulnerabilities by using sandboxing. Other types of virtualization and application microsegmentation may also mitigate the impact of some types of exploitation. Risks of additional exploits and weaknesses in these systems may still exist. 
|Disable or Remove Feature or Program||
Minimize available services to only those that are necessary.
Security applications that look for behavior used during exploitation such as Windows Defender Exploit Guard (WDEG) and the Enhanced Mitigation Experience Toolkit (EMET) can be used to mitigate some exploitation behavior.  Control flow integrity checking is another way to potentially identify and stop a software exploit from occurring.  Many of these protections depend on the architecture and target application binary for compatibility and may not work for all software or services targeted.
Segment networks and systems appropriately to reduce access to critical systems and services to controlled methods.
|Privileged Account Management||
Minimize permissions and access for service accounts to limit impact of exploitation.
|Threat Intelligence Program||
Develop a robust cyber threat intelligence capability to determine what types and levels of threat may use software exploits and 0-days against a particular organization.
Update software regularly by employing patch management for internal enterprise endpoints and servers.
Regularly scan the internal network for available services to identify new and potentially vulnerable services.
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. Also look for behavior on the endpoint system that might indicate successful compromise, such as abnormal behavior of the processes. This could include suspicious files written to disk, evidence of Process Injection for attempts to hide execution, evidence of Discovery, or other unusual network traffic that may indicate additional tools transferred to the system.
- CIS. (2017, May 15). Multiple Vulnerabilities in Microsoft Windows SMB Server Could Allow for Remote Code Execution. Retrieved April 3, 2018.
- National Vulnerability Database. (2017, June 22). CVE-2017-0176 Detail. Retrieved April 3, 2018.
- National Vulnerability Database. (2017, February 2). CVE-2016-6662 Detail. Retrieved April 3, 2018.
- National Vulnerability Database. (2017, September 24). CVE-2014-7169 Detail. Retrieved April 3, 2018.
- FireEye. (2015). APT28: A WINDOW INTO RUSSIA’S CYBER ESPIONAGE OPERATIONS?. Retrieved August 19, 2015.
- Smith, L. and Read, B.. (2017, August 11). APT28 Targets Hospitality Sector, Presents Threat to Travelers. Retrieved August 17, 2017.
- Microsoft. (2017, March 14). Microsoft Security Bulletin MS17-010 - Critical. Retrieved August 17, 2017.
- Symantec. (2018, July 18). The Evolution of Emotet: From Banking Trojan to Threat Distributor. Retrieved March 25, 2019.
- US-CERT. (2018, July 20). Alert (TA18-201A) Emotet Malware. Retrieved March 25, 2019.
- Mclellan, M.. (2018, November 19). Lazy Passwords Become Rocket Fuel for Emotet SMB Spreader. Retrieved March 25, 2019.
- Donohue, B.. (2019, February 13). https://redcanary.com/blog/stopping-emotet-before-it-moves-laterally/. Retrieved March 25, 2019.
- Schroeder, W., Warner, J., Nelson, M. (n.d.). Github PowerShellEmpire. Retrieved April 28, 2016.
- Gostev, A. (2012, May 28). The Flame: Questions and Answers. Retrieved March 1, 2017.
- Gostev, A. (2012, May 30). Flame: Bunny, Frog, Munch and BeetleJuice…. Retrieved March 1, 2017.
- Hromcova, Z. and Cherpanov, A. (2020, June). INVISIMOLE: THE HIDDEN PART OF THE STORY. Retrieved July 16, 2020.
- Chiu, A. (2016, June 27). New Ransomware Variant "Nyetya" Compromises Systems Worldwide. Retrieved March 26, 2019.
- US-CERT. (2017, July 1). Alert (TA17-181A): Petya Ransomware. Retrieved March 15, 2019.
- Nettitude. (2018, July 23). Python Server for PoshC2. Retrieved April 23, 2019.
- Falcone, R. and Lancaster, T.. (2019, May 28). Emissary Panda Attacks Middle East Government Sharepoint Servers. Retrieved July 9, 2019.
- Noerenberg, E., Costis, A., and Quist, N. (2017, May 16). A Technical Analysis of WannaCry Ransomware. Retrieved March 25, 2019.
- Berry, A., Homan, J., and Eitzman, R. (2017, May 23). WannaCry Malware Profile. Retrieved March 15, 2019.
- US-CERT. (2017, May 12). Alert (TA17-132A): Indicators Associated With WannaCry Ransomware. Retrieved March 25, 2019.
- Kimberly Goody, Jeremy Kennelly, Joshua Shilko, Steve Elovitz, Douglas Bienstock. (2020, October 28). Unhappy Hour Special: KEGTAP and SINGLEMALT With a Ransomware Chaser. Retrieved October 28, 2020.
- The DFIR Report. (2020, October 8). Ryuk’s Return. Retrieved October 9, 2020.
- The DFIR Report. (2020, October 18). Ryuk in 5 Hours. Retrieved October 19, 2020.
- Goodin, D. (2017, March 17). Virtual machine escape fetches $105,000 at Pwn2Own hacking contest - updated. Retrieved March 12, 2018.
- Nunez, N. (2017, August 9). Moving Beyond EMET II – Windows Defender Exploit Guard. Retrieved March 12, 2018.
- Wikipedia. (2018, January 11). Control-flow integrity. Retrieved March 12, 2018.