By Cluster25 Threat Intel Team
April 29, 2022

Panda_china-Jul-15-2022-01-49-28-85-AMNAIKON is the name of an APT (Advanced Persistent Threat) which is believed to originate from China. The Naikon hacker group was first tracked over a decade ago, back in 2010. Naikon APT hit the headlines in 2015 when malware researchers discovered the infrastructure used by cybercriminals. Thanks to this, one of the members of the hacker group was caught by law enforcement. After this oversight, cybersecurity analysts suggested that Naikon APT went out of business. However, Naikon has resurfaced in the last weeks.

The geolocalization and the sectors targeted by Naikon cyberattacks could likely suggest their intention to strategically attempt ASEAN members like Brunei, Cambodia, Indonesia, Laos, Malaysia, Myanmar, the Philippines, Singapore, Thailand, and Vietnam. Because of their more capitalist economic model, and their partnerships with the West, those countries could likely have important and classified foreign affairs or military information, which could likely be acquired and exploited by the Chinese threat actor. In fact, the group focused its previous attacks on high profile targets such as government agencies and military organizations in the South Asian region. Most government bodies targeted by Naikon APT cybercriminals are usually in the foreign affairs or science and technology sectors. Some state-owned businesses and companies have also reportedly been targeted by the threat actor.


By observing Naikon APT’s hacking arsenal, it was concluded that this group tends to conduct long-term intelligence and espionage operations, typical for a group that aims to conduct attacks on foreign governments and officials. To avoid detection and maximize the result, it changed different TTPs and tools over time.

In this attack analyzed by C25, the Chinese APT used a spear phishing email to deliver a beacon of a Red Team framework known as “Viper”. The killchain includes an artifact that is already known and that was attributed to Naikon one year ago and it is used to load and execute a custom shellcode. The target of this attack is currently unknown but with high probability, given the previous history of the attack perpetrated by the group, it might be a government institution from a South Asian country.

INITIAL ACCESS

The attack starts with a spear phishing email containing a weaponized document. The file, written in Chinese, seems to be a reply to a call for tenders. Its title translated in English is “Tender Documents for Centralized Procurement of Web Application Firewall (WAF) Equipment of China Mobile from 2022 to 2024”.

The Office document contains two different payloads that are hidden as document properties. As visible in the following VBA snippet, when opening the document, the Macro code extracts the embedded data from Comments and Subject properties and writes it in the file system.

The files are written under “%Temp%\rad543C7.tmp.ini” and “%Temp%\rad543C7.tmp.exe“. The VBA code is simple and short and doesn’t have trace of any obfuscation. The created INI file contains a payload encoded as hexstring, as shown below.

HEXINI LOADER

The file rad543C7.tmp.exe is an artifact already known to the community since the last year and it was named HexINI. It is a small executable that acts like a loader for a shellcode. Its name comes from its characteristic to be a loader for a hex-encoded shellcode saved as INI file in the same folder. So, also in this specific case the final code is contained into the same loader file, rad543C7.tmp.ini.

In the image is shown the core of HexINI loader. It simply opens and reads the INI file using the fopen and fread functions, then converts the hexadecimal string to a byte array. Then this array is loaded into process memory space using VirtualAlloc and memcpy. Finally, the code is executed on a new thread through the CreateThread function.

As shown in this picture, the hex bytes in the memory space the lpStartAddress is pointing to are the same already seen into the previous INI file.

SHELLCODE

Once the shellcode is executed, it proceeds with the creation of a suspended process of svchost.exe that can inject the final beacon.

The injection mechanism uses the classic flow composed by VirtualAllocEx, WriteProcessMemory and CreateRemoteThreadEx WinApi functions.

This remote thread seems to be a sort of HTTP beacon that tries to get new commands to execute every 7899 milliseconds from
https://175.27.164.228:57784/NYMLEDfq/IOH9E0Nq2YMEVQVXZgqYUAOI5wWcN5LMe

The beacon embeds the following user-agent:

Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.110 Safari/537.36

That corresponds to Google Chrome v58 on Windows 7.

At first glance, the code of this artifact might look like a CobaltStrike beacon. However, after a deep analysis C25 team discovered the beacon derives from a less popular RedTeam framework known as Viper.

On the command-and-control server, using a passive approach, C25 found the presence of a Viper framework and ARL dashboards (both tools are briefly described in the next section).

A graphic representation of the described kill-chain is shown below.

NAIKON ARSENAL

During the analysis it was discovered part of Naikon APT arsenal. Starting from what we observed we can assert that this Chinese group is using open-source tools like Viper and ARL (Asset Reconnaissance Lighthouse). Both tools seem to be developed by a Chinese programmer, as most of their documentation is written in Mandarin.

Viper [https://github.com/FunnyWolf/Viper]

Viper is a graphical penetration tool, which modularizes and weaponizes the tactics and technologies commonly used in the process of Intranet penetration. As stated in its Github page, Viper integrates 80+ modules, covering almost all the known Techniques (such as Resource Development, Initial Access, Execution, Persistence and so on).

Like CobaltStrike, Viper allows easy payload generation, such as Meterpreter, ReverseShell and other custom beacons.

In the following image is shown a Meterpreter usage example directly through the Viper GUI.

ARL [https://github.com/TophantTechnology/ARL]

ARL (Asset Reconnaissance Lighthouse) is a tool to assist security team or penetration tester to make reconnaissance and retrieval of assets, discovering existing weak points and attack surfaces.

The tool has a lot of functionalities such as port scanning and service identification, website fingerprinting, Domain name asset discovery and so on.

As visible from the Github page, the tool exposes a user-friendly Web view that make easier most of its functionalities.

INDICATORS OF COMPROMISE

CATEGORY TYPE VALUE
MALDOC SHA256 05936ed2436f57237e7773d3b6095e8df46821a62da49985c98be34136594ebd
EXE SHA256 8b831ee82975d43456ee861115272d3923e17f07a702eb057feeed8ce76ff4ca
FAKE INI SHA256 ee50160fdd7cacb7d250f83c48efa55ae0479e47a1eece9c08fe387453b9492a
SHELLCODE SHA256 eeb5dc51e3828ffbefc290dc1a973c5afc89ba7ff43ab337d5a3b3dc6ca4216f
C&C IPV4 175.27.164.228

ATT&CK MATRIX

TACTIC TECHNIQUE NAME
Initial Access T1566.001 Phishing: Spearphishing Attachment
Execution T1204 User Execution
Defense Evasion T1055 Process Injection
Defense Evasion T1406 Obfuscated Files or Information
Command and Control T1573 Encrypted Channel
Command and Control T1105 Ingress Tool Transfer
Command and Control T1071 Application Layer Protocol
Command and Control T1571 Non-Standard Port

HUNTING AND DETECTION

Customers with access to Cluster25 intelligence portal can get more indicators and threat hunting rules about this attack following the link

https://intelligence.cluster25.io/analysis/64a25cf2-e115-4526-b236-4a8e5275d8c3

For more information about this campaign it’s possibile to send an email to threatintel@cluster25.io

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