System Network Connections Discovery
Adversaries may attempt to get a listing of network connections to or from the compromised system they are currently accessing or from remote systems by querying for information over the network.
An adversary who gains access to a system that is part of a cloud-based environment may map out Virtual Private Clouds or Virtual Networks in order to determine what systems and services are connected. The actions performed are likely the same types of discovery techniques depending on the operating system, but the resulting information may include details about the networked cloud environment relevant to the adversary's goals. Cloud providers may have different ways in which their virtual networks operate.(Citation: Amazon AWS VPC Guide)(Citation: Microsoft Azure Virtual Network Overview)(Citation: Google VPC Overview) Similarly, adversaries who gain access to network devices may also perform similar discovery activities to gather information about connected systems and services.
Utilities and commands that acquire this information include netstat, "net use," and "net session" with Net. In Mac and Linux, netstat and lsof
can be used to list current connections. who -a
and w
can be used to show which users are currently logged in, similar to "net session". Additionally, built-in features native to network devices and Network Device CLI may be used (e.g. show ip sockets
, show tcp brief
).(Citation: US-CERT-TA18-106A)
Procedure Examples |
|
Name | Description |
---|---|
Lucifer |
Lucifer can identify the IP and port numbers for all remote connections from the compromised host.(Citation: Unit 42 Lucifer June 2020) |
Trojan.Karagany |
Trojan.Karagany can use netstat to collect a list of network connections.(Citation: Secureworks Karagany July 2019) |
Babuk |
Babuk can use “WNetOpenEnumW” and “WNetEnumResourceW” to enumerate files in network resources for encryption.(Citation: McAfee Babuk February 2021) |
APT38 |
APT38 installed a port monitoring tool, MAPMAKER, to print the active TCP connections on the local system.(Citation: FireEye APT38 Oct 2018) |
menuPass |
menuPass has used |
ShimRatReporter |
ShimRatReporter used the Windows function |
Zebrocy |
Zebrocy uses |
PoshC2 |
PoshC2 contains an implementation of netstat to enumerate TCP and UDP connections.(Citation: GitHub PoshC2) |
Poseidon Group |
Poseidon Group obtains and saves information about victim network interfaces and addresses.(Citation: Kaspersky Poseidon Group) |
Remsec |
Remsec can obtain a list of active connections and open ports.(Citation: Kaspersky ProjectSauron Technical Analysis) |
During Operation Wocao, threat actors collected a list of open connections on the infected system using `netstat` and checks whether it has an internet connection.(Citation: FoxIT Wocao December 2019) |
|
GravityRAT |
GravityRAT uses the |
netstat |
netstat can be used to enumerate local network connections, including active TCP connections and other network statistics.(Citation: TechNet Netstat) |
KONNI |
KONNI has used |
TeamTNT |
TeamTNT has run |
Andariel |
Andariel has used the |
Mustang Panda |
Mustang Panda has used |
CrackMapExec |
CrackMapExec can discover active sessions for a targeted system.(Citation: CME Github September 2018) |
Maze |
Maze has used the "WNetOpenEnumW", "WNetEnumResourceW”, “WNetCloseEnum” and “WNetAddConnection2W” functions to enumerate the network resources on the infected machine.(Citation: McAfee Maze March 2020) |
RATANKBA |
RATANKBA uses |
Turla |
Turla surveys a system upon check-in to discover active local network connections using the |
Carbon |
Carbon uses the |
Machete |
Machete uses the |
Torisma |
Torisma can use `WTSEnumerateSessionsW` to monitor remote desktop connections.(Citation: McAfee Lazarus Nov 2020) |
Cobalt Strike |
Cobalt Strike can produce a sessions report from compromised hosts.(Citation: Talos Cobalt Strike September 2020) |
Net |
Commands such as |
APT3 |
APT3 has a tool that can enumerate current network connections.(Citation: Symantec Buckeye)(Citation: FireEye Clandestine Fox)(Citation: evolution of pirpi) |
BlackEnergy |
BlackEnergy has gathered information about local network connections using netstat.(Citation: F-Secure BlackEnergy 2014)(Citation: Securelist BlackEnergy Nov 2014) |
Dtrack |
Dtrack can collect network and active connection information.(Citation: Securelist Dtrack) |
Operation Wocao |
Operation Wocao has collected a list of open connections on the infected system using netstat and checks whether it has an internet connection.(Citation: FoxIT Wocao December 2019) |
Sandworm Team |
Sandworm Team had gathered user, IP address, and server data related to RDP sessions on a compromised host. It has also accessed network diagram files useful for understanding how a host's network was configured.(Citation: US District Court Indictment GRU Unit 74455 October 2020)(Citation: Dragos Crashoverride 2018) |
Epic |
Epic uses the |
Comnie |
Comnie executes the |
Egregor |
Egregor can enumerate all connected drives.(Citation: NHS Digital Egregor Nov 2020) |
Cuba |
Cuba can use the function |
NETWIRE |
NETWIRE can capture session logon details from a compromised host.(Citation: FireEye NETWIRE March 2019) |
OSInfo |
OSInfo enumerates the current network connections similar to |
Sykipot |
Sykipot may use |
PyDCrypt |
PyDCrypt has used netsh to find RPC connections on remote machines.(Citation: Checkpoint MosesStaff Nov 2021) |
APT1 |
APT1 used the |
Waterbear |
Waterbear can use API hooks on `GetExtendedTcpTable` to retrieve a table containing a list of TCP endpoints available to the application.(Citation: Trend Micro Waterbear December 2019) |
PlugX |
PlugX has a module for enumerating TCP and UDP network connections and associated processes using the |
OilRig |
OilRig has used |
Duqu |
The discovery modules used with Duqu can collect information on network connections.(Citation: Symantec W32.Duqu) |
Magic Hound |
Magic Hound has used quser.exe to identify existing RDP connections.(Citation: DFIR Report APT35 ProxyShell March 2022) |
nbtstat |
nbtstat can be used to discover current NetBIOS sessions. |
Chimera |
Chimera has used |
MuddyWater |
MuddyWater has used a PowerShell backdoor to check for Skype connections on the target machine.(Citation: Trend Micro Muddy Water March 2021) |
SLOTHFULMEDIA |
SLOTHFULMEDIA can enumerate open ports on a victim machine.(Citation: CISA MAR SLOTHFULMEDIA October 2020) |
admin@338 |
admin@338 actors used the following command following exploitation of a machine with LOWBALL malware to display network connections: |
GALLIUM |
GALLIUM used |
CharmPower |
CharmPower can use `netsh wlan show profiles` to list specific Wi-Fi profile details.(Citation: Check Point APT35 CharmPower January 2022) |
SHOTPUT |
SHOTPUT uses netstat to list TCP connection status.(Citation: Palo Alto CVE-2015-3113 July 2015) |
APT41 |
APT41 has enumerated IP addresses of network resources and used the |
Conti |
Conti can enumerate routine network connections from a compromised host.(Citation: CarbonBlack Conti July 2020) |
MESSAGETAP |
After loading the keyword and phone data files, MESSAGETAP begins monitoring all network connections to and from the victim server. (Citation: FireEye MESSAGETAP October 2019) |
During Operation CuckooBees, the threat actors used the `net session`, `net use`, and `netstat` commands as part of their advanced reconnaissance.(Citation: Cybereason OperationCuckooBees May 2022) |
|
Kwampirs |
Kwampirs collects a list of active and listening connections by using the command |
Empire |
Empire can enumerate the current network connections of a host.(Citation: Github PowerShell Empire) |
During FunnyDream, the threat actors used netstat to discover network connections on remote systems.(Citation: Bitdefender FunnyDream Campaign November 2020) |
|
HEXANE |
HEXANE has used netstat to monitor connections to specific ports.(Citation: Kaspersky Lyceum October 2021) |
Sibot |
Sibot has retrieved a GUID associated with a present LAN connection on a compromised machine.(Citation: MSTIC NOBELIUM Mar 2021) |
SpeakUp |
SpeakUp uses the |
BackdoorDiplomacy |
BackdoorDiplomacy has used NetCat and PortQry to enumerate network connections and display the status of related TCP and UDP ports.(Citation: ESET BackdoorDiplomacy Jun 2021) |
Okrum |
Okrum was seen using NetSess to discover NetBIOS sessions.(Citation: ESET Okrum July 2019) |
APT32 |
APT32 used the |
Earth Lusca |
Earth Lusca employed a PowerShell script called RDPConnectionParser to read and filter the Windows event log “Microsoft-Windows-TerminalServices-RDPClient/Operational” (Event ID 1024) to obtain network information from RDP connections. Earth Lusca has also used netstat from a compromised system to obtain network connection information.(Citation: TrendMicro EarthLusca 2022) |
Tropic Trooper |
Tropic Trooper has tested if the localhost network is available and other connection capability on an infected system using command scripts.(Citation: TrendMicro Tropic Trooper May 2020) |
POWRUNER |
POWRUNER may collect active network connections by running |
USBferry |
USBferry can use |
Flagpro |
Flagpro has been used to execute |
QakBot |
QakBot can use |
Ke3chang |
Ke3chang performs local network connection discovery using |
Pupy |
Pupy has a built-in utility command for |
jRAT |
jRAT can list network connections.(Citation: Kaspersky Adwind Feb 2016) |
Ramsay |
Ramsay can use |
RedLeaves |
RedLeaves can enumerate drives and Remote Desktop sessions.(Citation: PWC Cloud Hopper Technical Annex April 2017) |
Volgmer |
Volgmer can gather information about TCP connection state.(Citation: Symantec Volgmer Aug 2014) |
Lazarus Group |
Lazarus Group has used |
Sliver |
Sliver can collect network connection information.(Citation: GitHub Sliver Netstat) |
Threat Group-3390 |
Threat Group-3390 has used `net use` and `netstat` to conduct internal discovery of systems. The group has also used `quser.exe` to identify existing RDP sessions on a victim.(Citation: SecureWorks BRONZE UNION June 2017) |
Aria-body |
Aria-body has the ability to gather TCP and UDP table status listings.(Citation: CheckPoint Naikon May 2020) |
Lizar |
Lizar has a plugin to retrieve information about all active network sessions on the infected server.(Citation: BiZone Lizar May 2021) |
Mitigations |
|
Mitigation | Description |
---|---|
System Network Connections Discovery Mitigation |
Identify unnecessary system utilities or potentially malicious software that may be used to acquire information about network connections, and audit and/or block them by using whitelisting (Citation: Beechey 2010) tools, like AppLocker, (Citation: Windows Commands JPCERT) (Citation: NSA MS AppLocker) or Software Restriction Policies (Citation: Corio 2008) where appropriate. (Citation: TechNet Applocker vs SRP) |
Detection
System and network discovery techniques normally occur throughout an operation as an adversary learns the environment. Data and events should not be viewed in isolation, but as part of a chain of behavior that could lead to other activities, such as Lateral Movement, based on the information obtained. Monitor processes and command-line arguments for actions that could be taken to gather system and network information. Remote access tools with built-in features may interact directly with the Windows API to gather information. Further, Network Device CLI commands may also be used to gather system and network information with built-in features native to the network device platform. Monitor CLI activity for unexpected or unauthorized use commands being run by non-standard users from non-standard locations. Information may also be acquired through Windows system management tools such as Windows Management Instrumentation and PowerShell.
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Связанные риски
Каталоги
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