TLP WHITE National Cybersecurity and Communications Integration Center INCIDENT REPORT DISCLAIMER This report is provided as is for informational purposes only The Department of Homeland Security DHS does not provide any warranties of any kind regarding any information contained within DHS does not endorse any commercial product or service referenced in this advisory or otherwise This document is distributed as TLP WHITE Subject to standard copyright rules TLP WHITE information may be distributed without restriction For more information on the Traffic Light Protocol see https www us-cert gov tlp Reference Number IR-ALERT-MED-17-093-01C April 27 2017 INTRUSIONS AFFECTING MULTIPLE VICTIMS ACROSS MULTIPLE SECTORS Executive Summary The National Cybersecurity and Communications Integration Center NCCIC has become aware of an emerging sophisticated campaign occurring since at least May 2016 that uses multiple malware implants Initial victims have been identified in several sectors including information technology energy healthcare and public health communications and critical manufacturing According to preliminary analysis threat actors appear to be leveraging stolen administrative credentials local and domain and certificates along with placing sophisticated malware implants on critical systems Some of the campaign victims have been IT service providers where credential compromises could potentially be leveraged to access customer environments Depending on the defensive mitigations in place the threat actor could possibly gain full access to networks and data in a way that appears legitimate to existing monitoring tools Although this activity is still under investigation NCCIC is sharing this information to provide organizations information for the detection of potential compromises within their organizations NCCIC will update this document as information becomes available To report activity related to this Incident Report Alert please contact NCCIC at NCCICCustomerService@hq dhs gov or 1-888-282-0870 1 of 20 TLP WHITE TLP WHITE Risk Evaluation NCCIC Cyber Incident Scoring System NCISS Rating Priority Level Color Yellow Medium A medium priority incident may affect public health or safety national security economic security foreign relations civil liberties or public confidence Details While NCCIC continues to work with a variety of victims across different sectors the adversaries in this campaign continue to affect several IT service providers To achieve operational efficiencies and effectiveness many IT service providers often leverage common core infrastructure that should be logically isolated to support multiple clients Intrusions into these providers create opportunities for the adversary to leverage stolen credentials to access customer environments within the provider network Figure 1 Structure of a traditional business network and an IT service provider network 2 of 20 TLP WHITE TLP WHITE Technical Analysis The threat actors in this campaign have been observed employing a variety of tactics techniques and procedures TTPs The actors use malware implants to acquire legitimate credentials then leverage those credentials to pivot throughout the local environment NCCIC is aware of several compromises involving the exploitation of system administrators' credentials to access trusted domains as well as the malicious use of certificates Additionally the adversary makes heavy use of PowerShell and the open source PowerSploit tool to enable assessment reconnaissance and lateral movement Command and Control C2 primarily occurs using RC4 cipher communications over port 443 to domains that change IP addresses Many of these domains spoof legitimate sites and content with a particular focus on spoofing Windows update sites Most of the known domains leverage dynamic DNS services and this pattern adds to the complexity of tracking this activity Listings of observed domains are found in this document's associated STIX package and xlsx file The indicators should be used to observe potential malicious activity on your network User impersonation via compromised credentials is the primary mechanism used by the adversary However a secondary technique to maintain persistence and provide additional access into the victim network is the use of malware implants left behind on key relay and staging machines In some instances the malware has only been found within memory with no on-disk evidence available for examination To date the actors have deployed multiple malware families and variants some of which are currently not detected by anti-virus signatures The observed malware includes PLUGX SOGU and REDLEAVES Although the observed malware is based on existing malware code the actors have modified it to improve effectiveness and avoid detection by existing signatures Both REDLEAVES and PLUGX have been observed being executed on systems via dynamiclink library DLL side-loading The DLL side-loading technique utilized by these malware families typically involves three files a non-malicious executable a malicious DLL loader and an encoded payload file The malicious DLL is named as one of the DLLs that the executable would normally load and is responsible for decoding and executing the payload into memory REDLEAVES Malware The most unique implant observed in this campaign is the REDLEAVES malware The REDLEAVES implant consists of three parts an executable a loader and the implant shellcode The REDLEAVES implant is a remote administration Trojan RAT that is built in Visual C and makes heavy use of thread generation during its execution The implant contains a number of functions typical of RATs including system enumeration and creating a remote shell back to the C2 3 of 20 TLP WHITE TLP WHITE Capabilities System Enumeration The implant is capable of enumerating the following information about the victim system and passing it back to the C2 system name system architecture x86 or x64 operating system major and minor versions amount of available memory processor specifications language of the user privileges of the current process group permissions of the current user system uptime IP address and primary drive storage utilization Command Execution The implant can execute a command directly inside a command shell using native Windows functionality by passing the command to run to cmd exe with the c option cmd exe c command Command Window Generation The implant can also execute commands via a remote shell that is generated and passed through a named pipe A command window is piped back to the C2 over the network as a remote shell or alternatively to another process or thread that can communicate with that pipe The implant uses the mutexRedLeavesCMDSimulatorMutex File System Enumeration The implant has the ability to enumerate data within a specified directory where it gathers filenames last file write times and file sizes Network Traffic Compression and Encryption The implant uses a form of LZO compression to compress data that is sent to its C2 After compression the data for this implant sample is then RC4-ciphered with the key 0x6A6F686E3132333400 this corresponds to the string john1234 with the null byte appended Network Communications REDLEAVES connects to the C2 over TCP port 443 but does not use the secure flag when calling the API function InternetOpenUrlW The data is not encrypted and there is no SSL handshake as would normally occur with port 443 traffic but rather the data is transmitted in the form that is generated by the RC4 cipher Current REDLEAVES samples that have been examined have a hard-coded C2 Inside the implant's configuration block in memory were the strings in Table 1 4 of 20 TLP WHITE TLP WHITE Table 1 REDLEAVES Sample Strings Found in C2 QN4869MD - mutex used to determine if the implant is already running Varies from sample to sample 2016-5-1-INCO -Unknown %windir system32 svchost exe - process that the implant was injected into john1234 with the null byte afterward - RC4 Key While the name of the initial mutex QN4869MD in this sample varies among REDLEAVES samples the RedLeavesCMDSimulatorMutex mutex name appears to be consistent Table 2 contains a sample of the implant communications to the domain windowsupdates dnset com over TCP port 443 Table 2 REDLEAVES Sample Beacon --- BEGIN SAMPLE BEACON --00000000 c1 0c 00 00 7a 8d 9b dc 88 00 00 00 z 0000000C 14 6f 68 6e 16 6f 68 6e c4 a4 b1 d1 c4 e6 24 eb ohn ohn $ 0000001C cf 49 81 a7 a1 c7 96 ff 6d 31 b4 48 8b 3e a3 c1 I m1 H 0000002C 92 e2 c3 7c e4 4c cf e9 e1 fa fb 6a fa 66 2c bf L j f 0000004C 7b 13 a7 30 17 3d eb fb d3 16 0e 96 83 21 2e 73 0 s 0000005C dc 44 a2 72 fb f4 5e d0 4d b7 85 be 33 cd 13 21 D r M 3 0000006C 3f e2 63 da da 5b 5e 52 9a 9c 20 36 69 cb cd 79 c R 6i y 0000007C 13 79 7a d4 ed 63 b7 41 5d 38 b4 c2 84 74 98 cd yz c A 8 t 0000008C f8 32 49 ef 2d e7 f2 ed 2I - 0000003C 5e 4b 72 6a f9 47 86 cd f1 cd 6d b5 24 79 3c 59 Krj G m $y --- END SAMPLE BEACON --- REDLEAVES network traffic has two 12-byte fixed-length headers in front of each RC4encrypted compressed payload The first header comes in its own packet with the second header and the payload following in a separate packet within the same TCP stream The last four bytes of the first header contain the number of the remaining bytes in little-endian format 0x88 in the sample beacon above The second header starting at position 0x0C is XOR'd with the first four bytes of the key that is used to encrypt the payload In the case of this sample those first four bytes would be john or 0x6a6f686e using the ASCII hex codes After the XOR operation the bytes in positions 0x0C through 0x0F contain the length of the decrypted and decompressed payload The bytes in positions 0x10 through 0x13 contain the length of the encrypted and compressed payload To demonstrate in the sample beacon the second header follows 0000000C 14 6f 68 6e 16 6f 68 6e c4 a4 b1 d1 The length of the decrypted and decompressed payload is 0x7e000000 in little-endian format 0x146f686e XOR 0x6a6f686e The length of the encrypted and compressed payload is 5 of 20 TLP WHITE TLP WHITE 0x7c000000 in little-endian 0x166f686e XOR 0x6a6f686e This is verified by referring back to the sample beacon which had the number of remaining bytes set to 0x88 and subtracting the length of the second header 0x88 - 0xC 0x7c Strings Note Use caution when searching based on strings as common strings may cause a large number of false positives Table 3 Strings Appearing in the Analyzed Sample of REDLEAVES Unique Ascii strings -------------------red_autumnal_leaves_dllmain dll windowsupdates dnset com windowsupdates dnset com windowsupdates dnset com 2016-5-10-INCO john1234 Feb 04 2015 127 0 0 1 169 254 tcp https http Unique Unicode strings -----------------RedLeavesCMDSimulatorMutex QN4869MD pipe NamePipe_MoreWindows network proxy type network proxy http_port network proxy http network proxy autoconfig_url network proxy a a-zA-Z0-9 b t c a-zA-Z d 0-9 h 0-9a-fA-F n r r n q ' ' ' w a-zA-Z z 0-9 6 of 20 TLP WHITE TLP WHITE Malware Execution Analysis File Name VeetlePlayer exe MD5 9d0da088d2bb135611b5450554c99672 File Size 25704 bytes 25 1 KB Description This is the executable that calls the exports located within libvlc dll File Name libvlc dll MD5 9A8C76271210324D97A232974CA0A6A3 File Size 33792 bytes 33 0 KB Description This is the loader and decoder for mtcReport ktc the combined shellcode and implant file File Name mtcReport ktc MD5 3045E77E1E9CF9D9657AEA71AB5E8947 File Size 231076 bytes 225 7 KB Description This is the encoded shellcode and implant file When this file is decoded the shellcode precedes the actual implant which resides at offset 0x1292 from the beginning of the shellcode in memory The implant has the MZ and PE flags replaced with the value 0xFF All three of these files must be present for execution of the malware to succeed When all files are present and the VeetlePlayer exe file is executed it will make calls to the following DLL exports within the libvlc dll file VLC_Version checks to see if its calling file is named VeetlePlayer exe If the calling file is named something else execution will terminate and no shellcode will be loaded VLC_Create reads in the contents of the file mtcReport ktc VLC_Init takes in the offset in which the encoded shellcode implant file is located and deobfuscates it After deobfuscation this export executes the shellcode VLC_Destroy does nothing other than perform a return 0 VLC_AddIntf and VLC_CleanUp simply call the export VLC_Destroy which returns 0 When the libvlc dll decodes the shellcode implant it calls the shellcode at the beginning of the data blob in memory The shellcode then activates a new instance of svchost exe and suspends it It then makes a call to WriteProcessMemory and inserts the implant with the damaged MZ and PE headers into its memory space It then resumes execution of svchost exe which runs the implant The resulting decoded shellcode with the implant file below it can have a variable MD5 based on how it is dumped from memory The MD5 checksums of two instances of decoded shellcode are 7 of 20 TLP WHITE TLP WHITE 1 ba4b4087370780dc988d55cbb9de885d 2 3d032ba5f73cbc398f1a77af92077cd8 Table 4 contains the implant resulting from the original implant's separation from the shellcode and the repair of its MZ and PE flags Table 4 Resulting Implant from Shellcode Separation File Name red_autumnal_leaves_dllmain dll MD5 3EBBFEEE3A832C92BB60B531F749230E File Size 226304 bytes 221 0 KB PE Compile Date 10 May 2016 During execution the file will create two mutexes called RedLeavesCMDSimulatorMutex and QN4869MD It checks the QN4869MD mutex to see if it is already running It will then perform initial enumeration of the system to include operating system versions number of processors RAM and CPU information PLUGX PLUGX is a sophisticated Remote Access Tool RAT operating since approximately 2012 Although there are now many variants of this RAT in existence today there are still characteristics common to most variants Typically PLUGX uses three components to install itself 1 A non-malicious executable 2 A malicious DLL installer 3 An encoded payload - the PLUGX RAT A non-malicious executable with one or more imports is used to start the installation process The executable will likely exist in a directory not normally associated with its use In some cases the actor may use an executable signed with a valid certificate and rename the DLL and encoded payload with file names that suggest they are related to the trusted file Importantly the actor seems to vary the encoding scheme used to protect the encoded payload to stifle techniques used by AV vendors to develop patterns to detect it The payload is either encoded with a single byte or encrypted and decompressed Recently NCCIC has observed a case where the encoded payload contains a decoding stub within itself beginning at byte zero The malware simply reads this payload and executes it starting at byte zero The stub then decodes and executes the rest of itself in memory Notably this stub varies in its structure and algorithm again stifling detection by signature based security software The PLUGX malware is never stored on disk in an unencrypted or decoded format When the initial executable is launched the imported library usually a separate DLL is replaced with a malicious version that in turn decodes and installs the third and final component which is 8 of 20 TLP WHITE TLP WHITE the PLUGX rat itself Typically the PLUGX component is obfuscated and contains no visible executable code until it is unpacked in memory protecting it from AV YARA scans while static During the evolution of these PLUGX compromises NCCIC noted an increasing implementation of protections of the actual decoded PLUGX in memory For example the most recent version we looked at implements a secure strings method which hides the majority of the common commands used by PLUGX This is an additional feature designed to thwart signature based security tools Once the PLUGX RAT is installed on the victim the actors has complete C2 capabilities of the victim system including the ability to take screenshots and download files from the compromised system The communications between the RAT installed on the victim system and the PLUGX C2 server are encoded to secure the communication and stifle detection by signature based network signature tools The advanced capabilities of PLUGX are implemented via a plugin framework Each plugin operates independently in its own unique thread within the service The modules may vary based on variants Table 5 lists the modules and capabilities contained within one sample recently analyzed by NCCIC Table 5 Modules and Capabilities of PLUGX Module Name Capability Disk wide range of system-related capabilities including file directory drive enumeration file directory creation create process and obtain environment variables Keylog logs keystrokes and saves data to log file Nethood enumerates the host's network resources via the Windows multiple provider router DLL Netstat set the state of a TCP connection or obtain the extended TCP or UDP tables lists of network endpoints available to a process of each active process on the host Option provides the ability to initiate a system shutdown adjust shutdown-related privileges for a given process and lock the user's workstation Portmap port mapping Process process enumeration termination and capability to obtain more in-depth information pertaining to each process e g CompanyName FileDescription FileVersion of each module loaded by the process Regedit create read update delete registry entries Screen capability to capture screenshots of the system Service start stop remove configure query services Shell remote shell access SQL enumerate SQL databases and available drivers execute SQL queries 9 of 20 TLP WHITE TLP WHITE Module Name Capability Telnet provides a telnet interface The PLUGX operator may dynamically add remove or update PLUGX plugins during runtime This provides the ability to dynamically adjust C2 capabilities based on the requirements of the C2 operator Network activity is often seen as POST requests similar to that shown in table 6 Network defenders can look to detect non-SSL HTTP traffic on port 443 which can be indicative of malware traffic The PLUGX malware is also seen using TCP ports 80 8080 and 53 Table 6 Sample PLUGX Beacon POST D15DB9E25ADA34EC9E559736 HTTP 1 1 Accept HX1 0 HX2 0 HX3 61456 HX4 1 User-Agent Mozilla 4 0 compatible MSIE 9 0 Windows NT 6 1 SLCC2 NET CLR 2 0 50727 NET4 0C NET4 0E Host sc weboot info 443 Content-Length 0 Cache-Control no-cache Even though the beacon went to port 443 which is commonly used for encrypted HTTP communications this traffic was plaintext HTTP as is common for this variant of PLUGX For IT Service Providers All organizations that provide IT services as a commodity for other organizations should evaluate their infrastructure to determine if related activity has taken place Active monitoring of network traffic for the indicators of compromise IOCs provided in this report as well as behavior analysis for similar activity should be conducted to identify C2 traffic In addition frequency analysis should be conducted at the lowest level possible to determine any unusual fluctuation in bandwidth indicative of a potential data exfiltration Both management and client systems should be evaluated for host indicators provided If an intrusion is suspected please reach out to the NCCIC at the contact information provided at the end of this report 10 of 20 TLP WHITE TLP WHITE For Private Organizations and Government Agencies All organizations should include the IOCs provided in their normal intrusion detection systems for continual analysis Organizations that determine their risk to be elevated due to alignment to the sectors being targeted unusual detected activity or other factors should conduct a dedicated investigation to identify any related activity Organizations which leverage external IT service providers should validate with their providers that due diligence is being conducted to validate if there are security concerns with their specific provider If an intrusion is suspected please reach out to the NCCIC at the contact information provided at the end of this report Detection NCCIC is providing a compilation of IOCs from a variety of sources to aid in the detection of this malware The IOCs provided in the associated STIX package and xlsx file were derived from various government commercial and publically available sources The sources provided does not constitute an exhaustive list and the U S Government does not endorse or support any particular product or vendor's information listed in this report However NCCIC includes this compilation here to ensure the distribution of the most comprehensive information This alert will be updated as additional details become available Table 7 Sources Referenced Source Title PaloAltoNetworks menuPass Returns with New Malware and New Attacks Against Japanese Academics and Organizations FireEye APT10 Menupass Team Renews Operations Focused on Nordic Private Industry operations Extend to Global Partners February 23 2017 10 14 00 AM 17-00001858 Version 2 CyLance The Deception Project A New Japanese-Centric Threat PwC BAE Systems Operation Cloud Hopper Exposing a systematic hacking operation with an unprecedented web of global victims April 2017 JPCERT CC RedLeaves-Malware Based on Open Source Rat http blog jpcert or jp 2017 04 redleaves---malware-based-on-open-sourcerat html NCC Group RedLeaves Implant-Overview National Cyber Security Centre Infrastructure Update Version 1 0 Reference March 17 2017 FireEye BUGJUICE Malware Profile April 05 2017 11 45 00 AM 17-00003261 Version 1 JPCERT CC ChChes- Malware that Communicates with C C Servers Using Cookie Headers http blog jpcert or jp 2017 02 chches-malware--93d6 html 11 of 20 TLP WHITE TLP WHITE NCCIC recommends monitoring activity to the following domains and IP addresses and scanning for evidence of the file hashes as potential indicators of infection Some of the IOCs provided may be associated with legitimate traffic Nevertheless closer evaluation is warranted if the IOCs are observed If these IOCs are found NCCIC can provide additional assistance in further investigations A comprehensive listing of IOCs can be found in the associated STIX package and xlsx file Network Signatures Table 8 REDLEAVES Network Signatures alert tcp any any - any any msg REDLEAVES Implant content 00 00 7a 8d 9b dc offset 2 depth 6 content 00 00 offset 10 depth 2 sid 314 alert tcp any - any any msg Suspicious PLUGX URI String content POST http_method content update id http_uri fast_pattern only pcre update id a-fA-F0-9 8 HTTP sid 101 Table 9 REDLEAVES YARA Signatures rule Dropper_DeploysMalwareViaSideLoading meta description Detect a dropper used to deploy an implant via side loading This dropper has specifically been observed deploying REDLEAVES PlugX author USG true_positive 5262cb9791df50fafcb2fbd5f93226050b51efe400c2924eecba97b7ce437481 drops REDLEAVES 6392e0701a77ea25354b1f40f5b867a35c0142abde785a66b83c9c8d2c14c0c3 drops plugx strings $UniqueString 2e 6c 6e 6b 0-14 61 76 70 75 69 2e 65 78 65 lnk near avpui exe $PsuedoRandomStringGenerator b9 1a 0-6 f7 f9 46 80 c2 41 88 54 35 8b 83 fe 64 Unique function that generates a 100 character pseudo random string condition any of them rule REDLEAVES_DroppedFile_ImplantLoader_Starburn meta description Detect the DLL responsible for loading and deobfuscating the DAT file containing shellcode and core REDLEAVES RAT author USG true_positive 7f8a867a8302fe58039a6db254d335ae StarBurn dll strings $XOR_Loop 32 0c 3a 83 c2 02 88 0e 83 fa 08 4-14 32 0c 3a 83 c2 02 88 0e 83 fa 10 Deobfuscation loop condition any of them 12 of 20 TLP WHITE TLP WHITE rule REDLEAVES_DroppedFile_ObfuscatedShellcodeAndRAT_handkerchief meta description Detect obfuscated dat file containing shellcode and core REDLEAVES RAT author USG true_positive fb0c714cd2ebdcc6f33817abe7813c36 handkerchief dat strings $RedleavesStringObfu 73 64 65 5e 60 74 75 74 6c 6f 60 6d 5e 6d 64 60 77 64 72 5e 65 6d 6d 6c 60 68 6f 2f 65 6d 6d This is 'red_autumnal_leaves_dllmain dll' XOR'd with 0x01 condition any of them rule REDLEAVES_CoreImplant_UniqueStrings meta description Strings identifying the core REDLEAVES RAT in its deobfuscated state author USG strings $unique2 RedLeavesSCMDSimulatorMutex nocase wide ascii $unique4 red_autumnal_leaves_dllmain dll wide ascii $unique7 NamePipe_MoreWindows wide ascii condition any of them Table 10 PLUGX Network Signatures alert tcp any any - any any msg Non-Std TCP Client Traffic contains 'HX1 3a ' 'HX2 3a ' 'HX3 3a ' 'HX4 3a ' PLUGX Variant sid XX rev 1 flow established to_server content Accept 3a 20 2a 2f 2a nocase content HX1 3a distance 0 within 6 fast_pattern content HX2 3a nocase distance 0 content HX3 3a nocase distance 0 content HX4 3a nocase distance 0 classtype nonstd-tcp priority X alert tcp any any - any any msg Non-Std TCP Client Traffic contains 'X-Session 3a ''X-Status 3a ''XSize 3a ''X-Sn 3a ' PLUGX sid XX rev 1 flow established to_server content X-Session 3a nocase fast_pattern content X-Status 3a nocase distance 0 content X-Size 3a nocase distance 0 content X-Sn 3a nocase distance 0 classtype nonstd-tcp priority X alert tcp any any - any any msg Non-Std TCP Client Traffic contains 'MJ1X 3a ' 'MJ2X 3a ' 'MJ3X 3a ' 'MJ4X 3a ' PLUGX Variant sid XX rev 1 flow established to_server content MJ1X 3a nocase fast_pattern content MJ2X 3a nocase distance 0 content MJ3X 3a nocase distance 0 content MJ4X 3a nocase distance 0 classtype nonstd-tcp priority X alert tcp any any - any any msg Non-Std TCP Client Traffic contains 'Cookies 3a ' 'Sym1 2e ' ' 2c Sym2 2e ' ' 2c Sym3 2e ' ' 2c Sym4 2e ' Chches Variant sid XX rev 1 flow established to_server content Cookies 3a nocase content Sym1 2e 0 3a nocase distance 0 fast_pattern content 2c Sym2 2e nocase distance 0 content 2c Sym3 2e nocase distance 0 content 2c Sym4 2e nocase distance 0 classtype nonstd-tcp priority X 13 of 20 TLP WHITE TLP WHITE Host Signatures Table 11 PLUGX and REDLEAVES YARA Signatures rule PLUGX_RedLeaves meta author US-CERT Code Analysis Team date 03042017 incident 10118538 date 2017 04 03 MD5_1 598FF82EA4FB52717ACAFB227C83D474 MD5_2 7D10708A518B26CC8C3CBFBAA224E032 MD5_3 AF406D35C77B1E0DF17F839E36BCE630 MD5_4 6EB9E889B091A5647F6095DCD4DE7C83 MD5_5 566291B277534B63EAFC938CDAAB8A399E41AF7D info Detects specific RedLeaves and PlugX binaries strings $s0 80343057403D2FD0010072F433C08BFF80343024403D2FD0010072F4 $s1 C Users user Desktop my_OK_2014 bit9 runsna Release runsna pdb $s2 d work plug4 0 shellcode $s3 shellcode shellcode XSetting h $s4 42AFF4276A45AA58474D4C4BE03D5B395566BEBCBDEDE9972872C5C4C5498228 $s5 8AD32AD002D180C23830140E413BCB7CEF6A006A006A00566A006A00 $s6 EB055F8BC7EB05E8F6FFFFFF558BEC81ECC8040000535657 $s7 8A043233C932043983C10288043283F90A7CF242890D18AA00103BD37CE2891514AA00106A006A00 6A0056 $s8 293537675A402A333557B05E04D09CB05EB3ADA4A4A40ED0B7DAB7935F5B5B08 $s9 RedLeavesCMDSimulatorMutex condition $s0 or $s1 or $s2 and $s3 or $s4 or $s5 or $s6 or $s7 or $s8 or $s9 Other Detection Methods Examine Port Protocol Mismatches Examine network traffic where the network port and protocol do not match such as plaintext HTTP over port 443 Administrative Share Mapping When a malicious actor tries to move laterally on a network one of the techniques is to mount administrative shares to perform operations like uploading and downloading resources or executing commands In addition tools like System Internals PSEXEC will mount the shares automatically for the user Since administrators may map 14 of 20 TLP WHITE TLP WHITE administrative shares legitimately while managing components of the network this must be taken into account Filter network traffic for SMB mapping events and group the events by source IP destination IP the mounted path providing a count of total mounts to that path the first map time and the last map time Collect Windows Event Logs - Event ID 5140 network share object was accessed can be used to track C$ and ADMIN$ mounts by searching the Share Name field VPN User authentication mismatch A VPN user authentication match occurs when a user account authenticates to an IP address but once connected the internal IP address requests authentication tokens for other users This may create false positives for legitimate network administrators but if this is detected organizations should verify that the administrative accounts were legitimately used VPN activity from VPS providers While this may also produce false positives VPN logins from Virtual Private Server VPS providers may be an indicator of VPN users attempting to hide their source IP and should be investigated Mitigations Properly implemented defensive techniques and programs make it more difficult for an adversary to gain access to a network and remain persistent yet undetected When an effective defensive program is in place actors should encounter complex defensive barriers Actor activity should also trigger detection and prevention mechanisms that enable organizations to contain and respond to the intrusion more rapidly There is no single or set of defensive techniques or programs that will completely avert all malicious activities Multiple defensive techniques and programs should be adopted and implemented in a layered approach to provide a complex barrier to entry increase the likelihood of detection and decrease the likelihood of a successful compromise This layered mitigation approach is known as defense-in-depth NCCIC mitigations and recommendations are based on observations made during the hunt analysis and network monitoring for threat actor activity combined with client interaction Whitelisting Enable application directory whitelisting through Microsoft Software Restriction Policy SRP or AppLocker Use directory whitelisting rather than trying to list every possible permutation of applications in an environment Safe defaults allow applications to run from PROGRAMFILES PROGRAMFILES X86 and SYSTEM32 All other locations 15 of 20 TLP WHITE TLP WHITE should be disallowed unless an exception is granted Prevent the execution of unauthorized software by using application whitelisting as part of the security hardening of operating systems insulating Enable application directory whitelisting via the Microsoft SRP or AppLocker Account Control Decrease a threat actor's ability to access key network resources by implementing the principle of least privilege Limit the ability of a local administrator account to login from a local interactive session e g Deny access to this computer from the network and prevent access via a Remote Desktop Protocol session Remove unnecessary accounts groups and restrict root access Control and limit local administration Make use of the Protected Users Active Directory group in Windows Domains to further secure privileged user accounts against pass-the-hash compromises Workstation Management Create a secure system baseline image and deploy to all workstations Mitigate potential exploitation by threat actors by following a normal patching cycle for all operating systems applications software and all third-party software Apply asset and patch management processes Reduce the number of cached credentials to one if a laptop or zero if a desktop or fixed asset Host Based Intrusion Detection Configure and monitor system logs through host-based intrusion detection system HIDS and firewall Deploy an anti-malware solution to prevent spyware adware and malware as part of the operating system security baseline Monitor antivirus scan results on a regular basis Server Management Create a secure system baseline image and deploy to all servers Upgrade or decommission end-of-life non Windows servers Upgrade or decommission servers running Windows Server 2003 and older versions Implement asset and patch management processes Audit for and disable unnecessary services 16 of 20 TLP WHITE TLP WHITE Server Configuration and Logging Establish remote server logging and retention Reduce the number of cached credentials to zero Configure and monitor system logs via a centralized security information and event management SIEM appliance Add an explicit DENY for %USERPROFILE% Restrict egress web traffic from servers In Windows environments utilize Restricted Admin mode or remote credential guard to further secure remote desktop sessions against pass-the-hash compromises Restrict anonymous shares Limit remote access by only using jump servers for such access Change Control Create a change control process for all implemented changes Network Security An Intrusion Detection System IDS should o Implement continuous monitoring o Send alerts to a SIEM tool o Monitor internal activity this tool may use the same tap points as the netflow generation tools Netflow Capture should o Set a minimum retention period of 180 days o Capture netflow on all ingress and egress points of network segments not just at the Managed Trusted Internet Protocol Services MTIPS or Trusted Internet Connections TIC locations Network Packet Capture PCAP o Retain PCAP data for a minimum of 24 hours o Capture traffic on all ingress and egress points of the network Use a virtual private network VPN o Maintain site-to-site VPN with customers o Authenticate users utilizing site-to-site VPNs through adaptive security appliance ASA Use authentication authorization and accounting AAA for controlling network access o Require Personal Identity Verification PIV authentication to an HTTPS page on the ASA in order to control access Authentication should also require explicit 17 of 20 TLP WHITE TLP WHITE o o o o rostering of PIV distinguished names DNs that are permitted to enhance the security posture on both networks participating in the site-to-site VPN Establish appropriate secure tunneling protocol and encryption Strengthen router configuration e g avoid enabling remote management over the Internet and using default IP ranges automatically logout after configuring routers use encryption Turn off Wi-Fi protected setup WPS enforce the use of strong passwords keep router firmware up-to-date and Improve firewall security e g enable auto updates revise firewall rules as appropriate implement whitelists establish packet filtering enforce the use of strong passwords and encrypt networks Conduct regular vulnerability scans of the internal and external networks and hosted content to identify and mitigate vulnerabilities Define areas within the network that should be segmented to increase visibility of lateral movement by an adversary and increase the defense in-depth posture Develop a process to block traffic to IP addresses and domain names that have been identified as being used to aid previous malicious activities Network Infrastructure Recommendations Ensure your networking equipment has the latest available operating system and patches Verify the integrity of network devices by following the National Security Agency NSA Network Device Integrity NDI methodology Host Recommendations Implement policies to block workstations-to-workstation remote desktop protocol RDP connections through group policy object GPO on Windows or a similar mechanism Store system logs of mission critical systems for at least one year within a SIEM Review the configuration of application logs to verify fields being recorded will contribute to an incident response investigation Users Management Immediately set the password policy to require complex passwords for all users minimum of 15 characters this new requirement should be enforced as user passwords expire Reduce the number of domain and enterprise administrator accounts Create non-privileged accounts for privileged users and ensure they use the nonprivileged account for all non-privileged access e g web browsing email access If possible use technical methods to detect or prevent browsing by privileged accounts 18 of 20 TLP WHITE TLP WHITE authentication to web proxies would enable blocking of domain administrators Use two-factor authentication e g security tokens for remote access and to any sensitive data repositories If soft tokens are used they should not exist on the same device that is requesting remote access laptop and instead should be on a telephone or other out-of-band device Create privileged role tracking o Create a change control process to all privilege escalations and role changes on user accounts o Enable alerts on privilege escalations and role changes and o Log privileged user changes in the environment and alert on unusual events Establish least privilege controls and Implement a security-awareness training program Best Practices Implement a vulnerability assessment and remediation program Encrypt all sensitive data in transit and at rest Create an insider threat program Assign additional personnel to review logging and alerting data Complete independent security not compliance audit Create an information sharing program Complete and maintain network and system documentation to aid in timely incident response including o network diagrams o asset owners o type of asset and o an up-to-date incident response plan 19 of 20 TLP WHITE TLP WHITE Contact Us For questions related to this report contact NCCIC 24 hours 7 days a week Include the report reference number in the subject line of all email correspondence Toll Free 1-888-282-0870 International 703-235-8832 Email NCCICCustomerService@us-cert gov Feedback NCCIC continuously strives to improve its products and services You can help by answering a few short questions about this product at the following URL https www us-cert gov forms feedback 20 of 20 TLP WHITE                     National Security Archive    Suite 701  Gelman Library  The George Washington University    2130 H Street  NW  Washington  D C  20037    Phone  202 994‐7000  Fax  202 994‐7005  nsarchiv@gwu edu