Exploitation of Remote Services

What the technique is

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 Discovery 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. […]

What MITRE says you would watch

• AN0327

  Correlates inbound network access to remote service ports (e.g., SMB/RPC 445/135, RDP 3389, WinRM 5985/5986) with near-time instability in the target service (crash, abnormal restart), suspicious child process creation under the service, and post-access lateral-movement behaviors. The chain indicates likely exploitation rather than normal administration.

• AN0328

  Links inbound network access to SSHD/SMB/NFS/Databases or custom daemons with subsequent daemon crash/restart, core dump, or spawning of shells/reverse shells from the service context, indicating remote exploitation.

• AN0329

  Detects exploitation targeting ESXi/vCenter by correlating attempts to reach known exploitable endpoints (OpenSLP 427, CIM 5989, Hostd/Vpxa HTTPS 443, ESXi SOAP) with vmkernel/hostd crashes, unexpected hostd/vpxa restarts, or new reverse/outbound connections from ESXi host/vCenter to internal assets.