Exploitation of Remote Services
|Exploitation of Remote Services|
|Platform||Linux, Windows, macOS|
|System Requirements||Unpatched software or otherwise vulnerable target. Depending on the target and goal, the system and exploitable service may need to be remotely accessible from the internal network.|
|Data Sources||Windows Error Reporting, Process Monitoring, File monitoring|
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 SMB1 and RDP2 as well as applications that may be used within internal networks such as MySQL3 and web server services.4
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.
- APT28 exploited a Windows SMB Remote Code Execution Vulnerability to conduct lateral movement.56
- Flame can use MS10-061 to exploit a print spooler vulnerability in a remote system with a shared printer in order to move laterally.7
Segment networks and systems appropriately to reduce access to critical systems and services to controlled methods. Minimize available services to only those that are necessary. Regularly scan the internal network for available services to identify new and potentially vulnerable services. Minimize permissions and access for service accounts to limit impact of exploitation.
Update software regularly by employing patch management for internal enterprise endpoints and servers. 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. Make it difficult for adversaries to advance their operation through exploitation of undiscovered or unpatched vulnerabilities by using sandboxing, if available. Other types of virtualization and application microsegmentation may also mitigate the impact of some types of exploitation. The risks of additional exploits and weaknesses in implementation may still exist.8
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.9 Control flow integrity checking is another way to potentially identify and stop a software exploit from occurring.10 Many of these protections depend on the architecture and target application binary for compatibility and may not work for all software or services targeted.
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.
- 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.
- Gostev, A. (2012, May 30). Flame: Bunny, Frog, Munch and BeetleJuice…. Retrieved March 1, 2017.
- 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.