A glimpse into the shadowy realm of a Chinese APT: detailed analysis of a ShadowPad intrusion

Authors: William Backhouse (@Will0x04), Michael Mullen (@DropTheBase64) and Nikolaos Pantazopoulos

Summary

tl;dr

This post explores some of the TTPs employed by a threat actor who was observed deploying ShadowPad during an incident response engagement.

Below provides a summary of findings which are presented in this blog post:

  • Initial access via CVE-2022-29464.
  • Successive backdoors installed – PoisonIvy, a previously undocumented backdoor and finally ShadowPad.
  • Establishing persistence via Windows Services to execute legitimate binaries which sideloads backdoors, including ShadowPad.
  • Use of information gathering tools such as ADFind and PowerView.
  • Lateral movement leveraging RDP and ShadowPad.
  • Use of 7zip for data collection.
  • ShadowPad used for Command and Control. 
  • Exfiltration of data.

ShadowPad

This blog looks to build on the work of other security research done by SecureWorks and PwC with firsthand experience of TTPs used in a recent incident where ShadowPad was deployed. ShadowPad is a modular remote access trojan (RAT) which is thought to be used almost exclusively by China-Based threat actors.  

Attribution

Based on the findings of our Incident Response investigation, NCC Group assesses with high confidence that the threat actor detailed in this article was a China-based Advanced Persistent Threat (APT).

This is based on the following factors

  • ShadowPad – Public reporting has previously indicated the distribution of ShadowPad is tightly controlled and is typically exclusive to China-based threat actors for use during espionage campaigns.
  • TTPs – Specific TTPs observed during the attack were found to match those previously observed by China-based threat actors, both within NCC Group incident response engagements and the wider security community.
  • Activity pattern analysis – The threat actor was typically active during the hours of 01:00 – 09:00 (UTC) which matches the working hours of China

TTPs

Initial Access

A recent vulnerability in WSO2, CVE-2022-29464 [3], was the root cause of the incident. The actor, amongst other attackers, was able to exploit the vulnerability soon after it was published to create web shells on a server.

The actor leveraged a web shell to load a backdoor, in this case PoisonIvy. This was deployed via a malicious DLL and leveraged DLL Search Order Hijacking, a tactic which was continuously leveraged throughout the attack.

Execution

Certutil.exe was used via commands issued on web shells to install the PoisonIvy backdoor on patient zero.

The threat actor leveraged command prompt and PowerShell throughout the incident.

Additionally, several folders named _MEI<random digits> were observed within the Windows\Temp folder. The digits in the folder name change each time a binary is compiled. These folders are created on a host when a python executable is compiled. Within these folders were the .pyd library files and DLL files. The created time for these folders matched the last modified time stamp of the complied binary within the shimcache.

Persistence

Run Keys and Windows services were used throughout in order to ensure the backdoors deployed obtained persistence.

Defense Evasion

The threat actor undertook significant anti-forensic actions on ShadowPad related files to evade detection. This included timestomping the malicious DLL and applying the NTFS attributes of hidden and system to the files. Legitimate but renamed Windows binaries were used to load the configuration file. The threat actor also leveraged a legitimate Windows DLL, secur32.dll, as the name of the configuration file for the ShadowPad backdoor.

All indicators of compromise, aside from backdoor modules and loaders, were removed from the hosts by the threat actor.

Credential Access

The threat actor was observed collecting all web browser credentials from all hosts across the environment. It is unclear at this stage how this was achieved with the evidence available.

Discovery

A vast array of tooling was used to scan and enumerate the network as the actor negotiated their way through it, these included but were not limited to the following:

  • AdFind
  • NbtScan
  • PowerView
  • PowerShell scripts to enumerate hosts on port 445
  • Tree.exe

Lateral Movement

Lateral movement was largely carried out using Windows services, particularly leveraging SMB pipes. The only interactive sessions observed were onward RDP sessions to customer connected sites.

Collection

In addition to the automated collection of harvested credentials, the ShadowPad keylogger module was used in the attack, storing the keystrokes in encrypted database files for exfiltration. The output of which was likely included in archive files created by the attacker, along with the output of network scanning and reconnaissance.

Command and Control

In total, three separate command and control infrastructures were identified, all of which utilised DLL search order hijacking / DLL side loading. The initial payload was PoisonIvy, this was only observed on patient zero. The threat actor went on to deploy a previously undocumented backdoor once they gained an initial foothold in the network, this framework established persistence via a service called K7AVWScn, masquerading as an older anti-virus product. Finally, once a firm foothold was established within the network the threat actor deployed ShadowPad. Notably, the ShadowPad module for the proxy feature was also observed during the attack to proxy C2 communications via a less conspicuous server.

Exfiltration

Due to the exfiltration capabilities of ShadowPad, it is highly likely to have been the method of exfiltration to steal data from the customer network. This is further cemented by a small, yet noticeable spike in network traffic to threat actor controlled infrastructure.

Recommendations

  • Searches for the documented IOCs should be conducted
  • If IOCs are identified a full incident response investigation should be conducted

ShadowPad Technical Analysis

Initialisation phase 

Upon execution, the ShadowPad core module enters an initialisation phase at which it decrypts its configuration and determines which mode it runs. In summary, we identified the following modes: 

Mode ID Description 
Injects itself to a specified process (specified in the ShadowPad configuration) and adds persistence to the compromised host.     In addition, if the compromised user belongs to a group with a SID starting with S-1-5-80- then the specified target process uses the token of ‘lsass’. 
Injects itself to a specified process (specified in the ShadowPad configuration) and executes the core code in a new thread.    In addition, if the compromised user belongs to a group with a SID starting with S-1-5-80 then the specified target process uses the token of ‘lsass’. 
Injects itself to a specified process (specified in the ShadowPad configuration).     In addition, if the compromised user belongs to a group with a SID starting with S-1-5-80 then the specified target process uses the token of ‘lsass’. 
16 Injects itself to a specified process (specified in the ShadowPad configuration) and creates/starts a new service (details are specified in the ShadowPad configuration), which executes the core code.     In addition, if the compromised user belongs to a group with a SID starting with S-1-5-80 then the specified target process uses the token of ‘lsass’. 
Table 1 – ShadowPad Modes

ANALYST NOTE: The shellcode is decrypted using a combination of bitwise XOR operations. 

Configuration storage and structure 

ShadowPad comes with an embedded encrypted configuration, which it locates by scanning its own shellcode (core module) with the following method (Python representation): 

for dword in range( len(data) ): 
  first_value = data[dword :dword+4] 
  second_value = data[dword+4:dword+8] 
  third_value = data[dword+8:dword+12] 
  fourth_value = data[dword+12:dword+16] 
  fifth_value = data[dword+16:dword+20] 
  sixth_value = data[dword+20:dword+24] 
 
  xor1 = int.from_bytes(second_value,'little') ^ 0x8C4832F1 
  xor2 = int.from_bytes(fourth_value,'little') ^ 0xC3BF9669 
  xor3 = int.from_bytes(sixth_value,'little') ^  0x9C2891BA 

  if xor1 == int.from_bytes(first_value,'little') and xor2 ==    int.from_bytes(third_value,'little') and xor3 == int.from_bytes(fifth_value,'little'): 
     print(f"found: {dword:02x}") 
     encrypted = data[dword:] 
     break 
 

After locating it successfully, it starts searching in it for a specified byte that represents the type of data (e.g., 0x02 represents an embedded module). In total, we have identified the following types: 

ID Description 
0x02 Embedded ShadowPad module. 
0x80 ShadowPad configuration. It should start with the DWORD value 0x9C9D22EC. 
0x90 XOR key used during the generation of unique names (e.g., registry key name) 
0x91 DLL loader file data. 
0x92 DLL loader file to load. File might have random appended data (Depends on the config’s flag at offset 0x326). 
0xA0 Loader’s filepath 
Table 2 – Shadowpad Data Types 

Once one of the above bytes are located, ShadowPad reads the data (size is defined before the byte identifier) and appends the last DWORD value to the hardcoded byte array ‘1A9115B2D21384C6DA3C21FCCA5201A4’. Then it hashes (MD5) the constructed byte array and derives an AES-CBC 128bits key and decrypts the data. 

In addition, ShadowPad stores, in an encrypted format, the following data in the registry with the registry key name being unique (based on volume serial number of C:\) for each compromised host: 

  1. ShadowPad configuration (0x80) data. 
  2. Proxy configuration. Includes proxy information that ShadowPad requires. These are the network communication protocol, domain/IP proxy and the proxy port. 
  3. Downloaded modules. 

ShadowPad Network Servers 

ShadowPad starts two TCP/UDP servers at 0.0.0.0. The port(s) is/are specified in the ShadowPad configuration. These servers work as a proxy between other compromised hosts in the network. 

In addition, ShadowPads starts a raw socket server, which receives data and does one of the following tasks (depending on the received data): 

  1. Updates and sets proxy configuration to SOCKS4 mode. 
  2. Updates and sets proxy configuration to SOCKS5 mode. 
  3. Updates and sets proxy configuration to HTTP mode. 

Network Communication 

ShadowPad supports a variety of network protocols (supported by dedicated modules). For all of them, ShadowPad uses the same procedure to store and encrypt network data. The procedure’s steps are: 

  1. Compress the network data using the QuickLZ library module. 
  2. Generates a random DWORD value, which is appended to the byte array                  ‘1A9115B2D21384C6DA3C21FCCA5201A4’. Then, the constructed byte array is        hashed (MD5) and an AES-CBC 128bits key is derived (CryptDeriveKey). 
  3. The data is then encrypted using the generated AES key. In addition, Shadowpad        encrypts the following data fields using bitwise XOR operations: 
  1. Command/Module ID:  Command/Module ID ^  ( 0x1FFFFF * Hashing_Key – 0x2C7BEECE ) 
  2. Data_Size: Data_Size ^ ( 0x1FFFFFF * 0x7FFFFF * ( 0x1FFFFF * Hashing_Key – 0x2C7BEECE ) – 0x536C9757 – 0x7C06303F )  
  3. Command_Execution_State: Command_Execution_State ^ 0x7FFFFF * (0x1FFFFF * Hashing_Key – 0x2C7BEECE) – 0x536C9757 

As a last step, ShadowPad encapsulates the above generated data into the following        structure: 

struct Network_Packet 
{ 
 DWORD Hashing_Key; 
 DWORD Command_ID_Module_ID; 
 DWORD Command_Execution_State; //Usually contains any error codes. 
 DWORD Data_Size; 
 byte data[Data_Size]; 
}; 

If any server responds, it should have the same format as above. 

Network Commands and Modules 

During our analysis, we managed to extract a variety of ShadowPad modules with most of them having their own set of network commands. The table below summarises the identified commands of the modules, which we managed to recover. 

Module Command ID Description 
Main module 0xC49D0031              First command sent to the C2 if the commands fetcher function does not run in a dedicated thread. 
Main module 0xC49D0032  First command sent to the C2 if the commands fetcher function does run in a dedicated thread. 
Main module 0xC49D0033 Fingerprints the compromised host and sends the information to the C2. 
Main module 0xC49D0032 (Received) Executes the network command fetcher function in a thread. 
Main module     0xC49D0034              Sents an empty reply to the C2. 
Main module     0xC49D0037             Echoes the server’s reply. 
Main module 0xC49D0039 Sends number of times the Shadowpad files were detected to be deleted. 
Main module     0xC49D0016              Deletes Shadowpad registry keys. 
Main module     0xC49D0035              Enters sleep mode for 3 seconds in total. 
Main module     0xC49D0036              Enters sleep mode for 5 seconds in total. 
Main module     0xC49D0010              Retrieves Shadowpad execution information. 
Main module     0xC49D0012              Updates Shadowpad configuration (in registry). 
Main module     0xC49D0014              Deletes Shadowpad module from registry. 
Main module     0xC49D0015              Unloads a Shadowpad module. 
Main module     0xC49D0020              Retrieves Shadowpad current configuration (from registry). 
Main module     0xC49D0021              Updates the Shadowpad configuration in registry and (re)starts the TCP/UDP servers. 
Main module     0xC49D0022              Deletes Shadowpad registry entries and starts the TCP/UDP servers.   
Main module     0xC49D0050              Retrieves Shadowpad proxy configuration from registry. 
Main module     0xC49D0051              Updates Shadowpad proxy configuration. 
Main module     0xC49D0052              Updates Shadowpad proxy configuration by index. 
Main module     0xC49D0053              Sets Shadowpad proxy configuration bytes to 0 
Main module     Any Module ID           Loads and initialises the specified module ID. 
Files manager module   0x67520006       File operations (copy,delete,move,rename). 
Files manager module   0x67520007       Executes a file. 
Files manager module   0x67520008       Uploads/Downloads file to/from C2. 
Files manager module   0x6752000A       Searches for a specified file. 
Files manager module   0x6752000C       Downloads a file from a specified URL. 
Files manager module   0x67520005       Timestomp a file. 
Files manager module   0x67520000       Get logical drives information. 
Files manager module   0x67520001       Searches recursively for a file. 
Files manager module   0x67520002       Checks if file/directory is writable. 
Files manager module   0x67520003       Creates a directory. 
Files manager module   0x67520004       Gets files list in a given directory 
TCP/UDP module         0x54BD0000       Loads TCP module and proxy data via it. 
TCP/UDP module         0x54BD0001       Proxies UDP network data. 
Desktop module         0x62D50000       Enumerates monitors. 
Desktop module         0x62D50001       Takes desktop screenshot. 
Desktop module         0x62D50002       Captures monitor screen. 
Desktop module         0x62D50010       Gets desktop module local database file path.  
Desktop module         0x62D50011       Reads and sends the contents of local database file to the C2. 
Desktop module         0x62D50012 Writes to local database file and starts a thread that constantly takes desktop screenshots. 
Processes manager module 0x70D0000     Gets processes list along with their information 
Processes manager module 0x70D0001     Terminates a specified process 
Network Connections module 0x6D0000    Gets TCP network table. 
Network Connections module 0x6D0001    Gets UDP network table.   
PIPEs module 0x23220000   Reads/Writes data to PIPEs. 
Propagation module   0x2C120010    Get module’s configuration. 
Propagation module   0x2C120011    Transfer network data between C2 and PIPEs. 
Propagation module   0x2C120012 Constant transfer of network data between C2 and PIPEs. 
Propagation module   0x2C120013 Transfer network data between C2 and PIPEs. 
Propagation module   0x2C120014          Constant transfer of network data between C2 and PIPEs. 
Propagation module   0x2C120015 Transfer network data between C2 and PIPEs. 
Propagation module   0x2C120016 Constant transfer of network data between C2 and PIPEs. 
Propagation module 0x2C120017 Transfer network data between C2 and PIPEs. 
Propagation module 0x2C120018 Transfer network data between C2 and PIPEs. 
Scheduled tasks module 0x71CD0000   Gets a list of the scheduled tasks. 
Scheduled tasks module 0x71CD0001   Gets information of a specified scheduled task. 
Wi-Fi stealer module 0xDC320000 Collects credentials/information of available Wi-Fi devices. 
Network discovery module 0xF36A0000 Collects MAC addresses. 
Network discovery module 0xF36A0001 Collects IP addresses information. 
Network discovery module 0xF36A0003 Port scanning. 
Console module 0x329A0000            Starts a console mode in the compromised host. 
Keylogger module   0x63CA0000         Reads the keylogger file and sends its content to the C2. 
Keylogger module   0x63CA0001 Deletes keylogger file. 
Table 3 – Modules Network Commands 

Below are listed the available modules, which do not have network commands (Table 3). 

Module ID Description 
E8B5 QUICKLZ library module. 
7D82 Sockets connection module (supports SOCKS4, SOCKS5 and HTTP). 
C7BA TCP module. 
Table 4 – Available modules without network commands 

Below are listed the modules that we identified after analysing the main module of ShadowPad but were not recovered. 

Module ID      Description 
0x25B2         UDP network module. 
0x1FE2         HTTP network module. 
0x9C8A         HTTPS network module. 
0x92CA         ICMP network module 
0x64EA Unknown 
Table 5 – Non-Recovered ShadowPad Modules

Misc 

  1. ShadowPad uses a checksum method to compare certain values (e.g., if it runs under        certain access rights). This method has been implemented below in Python: 
ror = lambda val, r_bits, max_bits: \ 
((val & (2**max_bits-1)) >> r_bits%max_bits) | \ 
(val << (max_bits-(r_bits%max_bits)) & (2**max_bits-1)) 
rounds = 0x80 

data = b"" 
output = 0xB69F4F21 
max_bits = 32 
counter = 0 

for i in range( len(data) ): 
 data_character = data[counter] 
 if (data_character - 97)&0xff <= 0x19: 
  data_character &= ~0x20&0xfffffff 
  counter +=1 
  output = (data_character + ror(output, 8,32)) ^ 0xF90393D1 
  print ( hex( output )) 
  • Under certain modes, ShadowPad chooses to download and inject a payload from its        command-and-control server. ShadowPad parses its command-and-control server        domain/IP address and sends a HTTP request. The reply is expected to be a payload,        which ShadowPad injects into another process. 
          

ANALYST NOTE: In case the IP address/Domain includes the character ‘@’,                      ShadowPad decrypts it with a custom algorithm. 

Indicators of Compromise

IOCIndicator TypeDescription
C:\wso2is-4.6.0\BVRPDiag.exeFile PathLegitimate executable to sideload PoisonIvy
C:\wso2is-4.6.0\BVRPDiag.tsiFile Path 
C:\wso2is-4.6.0\BVRPDiag.dllFile PathPoisonIvy
C:\wso2is-4.6.0\ModemMOH.dllFile Path
C:\Windows\System32\spool\drivers\color\K7AVWScn.dllFile PathPreviously undocumented C2 framework
C:\Windows\System32\spool\drivers\color\K7AVWScn.docFile PathUnknown file in the same location as PosionIvy
C:\Windows\System32\spool\drivers\color\K7AVWScn.exeFile PathLegitimate executable to sideload PoisonIvy
C:\Windows\System32\spool\drivers\color\secur32.dllFile PathShadowPad DLL
C:\Windows\System32\spool\drivers\color\secur32.dll.datFile PathShadowPad Encrypted Configuration
C:\Windows\System32\spool\drivers\color\WindowsUpdate.exeFile PathLegitimate executable to sideload ShadowPad
C:\Windows\Temp\WinLog\secur32.dllFile PathShadowPad DLL
C:\Windows\Temp\WinLog\secur32.dll.datFile PathShadowPad Encrypted Configuration
C:\Windows\Temp\WinLog\WindowsEvents.exeFile PathLegitimate executable to sideload ShadowPad
C:\ProgramData\7z.dllFile PathArchiving tool
C:\ProgramData\7z.exeFile PathArchiving tool
C:\Users\Public\AdFind.exeFile PathReconnaissance tooling
C:\Users\Public\nbtscan.exeFile PathReconnaissance tooling
C:\Users\Public\start.batFile PathUnknown batch script, suspected to start execution of mimikatz
C:\Users\Public\t\64.exeFile PathUnknown executable, suspected mimikatz
C:\Users\Public\t\7z.exeFile Path Archiving tool
C:\Users\public\t\browser.exeFile PathUnknown attacker executable
C:\Users\Public\t\nircmd.exeFile PathNirCmd is a small command-line utility that allows you to do some useful tasks without displaying any user interface.
C:\users\public\t\test.batFile PathUnknown attacker batch script
C:\Users\Public\test.batFile PathUnknown attacker batch script
C:\Users\Public\test.exeFile PathUnknown attacker executable
C:\Users\Public\test\Active Directory\ntds.ditFile PathStaging location for NTDS dump
C:\Users\Public\test\registry\SECURITYFile PathStaging location for registry dump
C:\Users\Public\test\registry\SYSTEMFile PathStaging location for registry dump
C:\Users\Public\WebBrowserPassView.exeFile PathNirSoft tool for recovering credentials from web browsers.
C:\Windows\debug\adprep\P.batFile PathUnknown attacker batch script
C:\Windows\system32\spool\drivers\affair.exeFile PathUnknown attacker executable
C:\Windows\System32\spool\drivers\color\SessionGopher.ps1File PathDecrypts saved session information for remote access tools.
C:\windows\system32\spool\drivers\color\tt.batFile PathUnknown attacker batch script
C:\Windows\Temp\best.exeFile PathTree.exe
ip445.ps1File NameUnknown PowerShell script suspected to be related to network reconnaissance
ip445.txtFile NameSuspected output file for ip445.ps1
nbtscan.exeFile NameAttacker tooling
SOFTWARE: Classes\CLSID\*\42BF3891Registry KeyEncrypted ShadowPad configuration
SOFTWARE: Classes\CLSID\*\45E6A5BERegistry KeyEncrypted ShadowPad configuration
SOFTWARE: Classes\CLSID\*\840EE6F6Registry KeyEncrypted ShadowPad configuration
SOFTWARE: Classes\CLSID\*\9003BDD0Registry KeyEncrypted ShadowPad configuration
Software:Classes\CLSID\*\51E27247Registry KeyEncrypted ShadowPad configuration
Software\Microsoft\*\*\009F24BCCEA54128C2344E03CEE577E12504DD569C8B48AB8B7EAD5249778643Registry KeyEncrypted ShadowPad module
Software\Microsoft\*\*\5F336A90564002BE360DF63106AA7A7568829C6C084E793D6DC93A896C476204Registry KeyEncrypted ShadowPad module
Software\Microsoft\*\*\FF98EFB4C7680726BF336CEC477777BB3BEB73C7BAA1A5A574C39E7F4E804585Registry KeyEncrypted ShadowPad module
D1D0E39004FA8138E2F2C4157FA3B44BMD5 HashPoisenIvy DLL
54B419C2CAC1A08605936E016D460697MD5 HashUndocumented backdoor DLL
B426C17B99F282C13593954568D86863MD5 HashUndocumented backdoor related file
7504DEA93DB3B8417F16145E8272BA08MD5 HashShadowPad DLL
D99B22020490ECC6F0237EFB2C3DEF27MD5 HashShadowPad DLL
1E6E936A0A862F18895BC7DD6F607EB4MD5 HashShadowPad DLL
A6A19804248E9CC5D7DE5AEA86590C63MD5 HashShadowPad DLL
4BFE4975CEAA15ED0031941A390FAB55MD5 HashShadowPad DLL
87F9D1DE3E549469F918778BD637666DMD5 HashShadowPad DLL
8E9F8E8AB0BEF7838F2A5164CF7737E4MD5 HashShadowPad DLL

Mitre Att&ck

TacticTechniqueIDDescription
Initial AccessExploit Public-Facing ApplicationsT1190Initial access was gained via the threat actor exploiting CVE-2022-29464 to create a web shell
ExecutionCommand and Scripting Interpreter: PowerShellT1059:001PowerShell based tools PowerView and SessionGopher were executed across the estate for reconnaissance and credential harvesting. Additionally, hands on keyboard commands were identified as being executed to confirm which version of the malware was present.
ExecutionCommand and Scripting Interpreter: Windows Command ShellT1059:003A scheduled task used by the threat actor was used to launch a Windows Command Shell. The purpose is not known.
ExecutionCommand and Scripting Interpreter: PythonT1059:006Several compiled python binaries were identified. It is likely the binaries related to the creation of an FTP server.
ExecutionScheduled Task/Job: Scheduled TaskT1053A scheduled task named “update” was observed and configured to execute a command prompt on multiple hosts throughout the environment. Upon successful execution of the task the threat actor then deleted the task from the host
ExecutionExploitation for Client ExecutionT1203The threat actor leveraged CVE-2022-29464 to deploy web shells and allow remote command execution on patient zero.
ExecutionWindows Management Instrumentation (WMI)T1047WMI was used by the threat actor to carry out reconnaissance activity.
PersistenceBoot or Logon Autostart Execution: Registry Run Keys / Startup FolderT1547.001A run key for the local administrator was created to execute the malicious backdoor.
PersistenceCreate or Modify System Process: Windows ServiceT1543.003Two malicious services were deployed widely across the estate for persistence of the backdoors. Both services execute a legitimate binary which is stored in the same location as a malicious DLL, when executed the legitimate binary would side load the malicious DLL containing the backdoor.
Privilege EscalationValid Accounts: Domain AccountsT1078.002The threat actor was primarily using domain administrator credentials to move laterally throughout the attack, allowing them to blend in with legitimate administrator activity.
Defence EvasionImpair Defenses: Downgrade AttackT1562.010The threat actor was observed utilising PowerShell downgrades, this is typically used by threat actors to avoid the script logging capabilities of PowerShell version 5+
Defence EvasionIndicator Removal on Host: File DeletionT1070.004The threat actor routinely removed the majority of tooling deployed throughout the attack from hosts upon completion of their objectives.
Defence EvasionIndicator Removal on Host: TimestompT1070.006The threat actor timestomped all files relating to the backdoors including the legitimate binary and the malicious DLL.
Defence EvasionModify RegistryT1112The modules for ShadowPad were stored within the registry in an encrypted format. The keys for the stored data are generated depending on the volume serial number of the host.
Defence EvasionObfuscated Files or InformationT1027The ShadowPad configuration was stored within an encrypted registry hive. The keylogger module of ShadowPad created an encrypted output file on the host.
Defence EvasionMasquerading: Rename System UtilitiesT1036.003The threat actor leveraged a legitimate Windows DLL, secur32.dll, as the name of the configuration file for the ShadowPad backdoor.
Defence EvasionProcess Injection: Process HollowingT1055.012Upon execution ShadowPad spawns a sacrificial process, which then utilises the technique of process hollowing to inject into the process.  
Defence EvasionHide Artefacts: Hidden Files and DirectoriesT1564.001Several malicious files were identified as having the NTFS attribute of hidden.
Defence EvasionHijack Execution Flow: DLL Search Order HijackingT1574.001The backdoors leveraged DLL Search Order Hijacking.
Credential AccessCredentials from Password Stores: Credentials from Web BrowsersT1555:003The NirSoft tool WebBrowserPassView.exe was also identified as being executed by the attacker.
Credential AccessCredentials from Password Stores: Windows Credential ManagerT1555.004Credential harvesting which indicated credentials from Windows Credential Manager were collected was identified on a domain controller.
Credential AccessOS Credential Dumping: LSASS MemoryT1003.001ProcDump.exe was leveraged on patient zero during the attack in order to dump credentials stored in the process memory of Local Security Authority Subsystem Service (LSASS).
Credential AccessOS Credential Dumping: NTDST1003.003The NTDS.dit was dumped and exfiltrated from a domain controller for each domain.
Credential AccessUnsecured Credentials: Credentials in FilesT1552.001Several instances of passwords in plaintext files were observed on hosts where ShadowPad was installed/
Credential AccessInput Capture: KeyloggingT1056:001ShadowPad instances had a Keylogger module installed.
DiscoveryFile and Directory DiscoveryT1083Tree.exe was used to enumerate files and directories on compromised hosts.
DiscoveryNetwork Share DiscoveryT1135A PowerShell script named ip445.ps1 was used throughout the attack to enumerate network shares across the Windows estate.
DiscoverySystem Network Configuration DiscoveryT016AdFind.exe can extract subnet information from Active Directory.
DiscoveryAccount Discovery: Domain AccountT1087.002AdFind.exe can enumerate domain users.
DiscoveryDomain Trust DiscoveryT1482AdFind.exe can gather information about organizational units (OUs) and domain trusts from Active Directory.
DiscoveryPermission Groups Discovery: Domain GroupsT1069AdFind.exe can enumerate domain groups.
DiscoveryRemote System DiscoveryT1018AdFind.exe has the ability to query Active Directory for computers.
Lateral MovementRemote Services: Remote Desktop ProtocolT1021.001RDP was used by the threat actor to laterally move. It is unknown whether this was a deliberate act to move estates or if the threat actor was attempting to move to another domain.
Lateral MovementRemote Services: SMB/Windows Admin SharesT1021.002The Powerview module of Powersploit was used to enumerate all SMB shares across the environment.
Lateral MovementRemote Services: Windows Remote ManagementT1021.006WinRM was used by the actor during periods of network reconnaissance.
Lateral MovementRemote Services: Distributed Component Object ModelT1021.003Anti-virus alerts showed the threat actor as utilising WMI to laterally move to hosts across the network.
CollectionAutomated CollectionT1119Large scale credential harvesting was conducted against remote hosts from a domain controller.
CollectionData Staged: Remote Data StagingT1074.002Credentials harvested by the threat actor were collected on a domain controller, prior to exfiltration.
CollectionInput Capture: KeyloggingT1056.001ShadowPad instances had a Keylogger module installed which allowed them to capture the input of interactive sessions. The output was stored on disk in encrypted database files.
CollectionArchive Collected Data: Archive via UtilityT1560.001The actor was routinely observed archiving collected data via 7zip.
Command and ControlEncrypted ChannelT1573ShadowPad configurations indicated Command and Control communications were sent via port 443.
Command and ControlProxy: Internal ProxyT1090.001ShadowPad instances had a Proxy module installed. It was identified that a proxy module was installed and was interacting via port 445.
ExfiltrationExfiltration Over C2 ChannelT1041ShadowPad has the capability to exfiltrate data.

[1] https://www.secureworks.com/research/shadowpad-malware-analysis

[2] https://www.pwc.co.uk/issues/cyber-security-services/research/chasing-shadows.html

[3] https://nvd.nist.gov/vuln/detail/CVE-2022-29464