McAfee Defender’s Blog: Operation Dianxun

Operation Dianxun Overview

In a recent report the McAfee Advanced Threat Research (ATR) Strategic Intelligence team disclosed an espionage campaign, targeting telecommunication companies, named Operation Diànxùn.

The tactics, techniques and procedures (TTPs) used in the attack are like those observed in earlier campaigns publicly attributed to the threat actors RedDelta and Mustang Panda. Most probably this threat is targeting people working in the telecommunications industry and has been used for espionage purposes to access sensitive data and to spy on companies related to 5G technology.

While the initial vector for the infection is not entirely clear, the McAfee ATR team believes with a medium level of confidence that victims were lured to a domain under control of the threat actor, from which they were infected with malware which the threat actor leveraged to perform additional discovery and data collection. It is our belief that the attackers used a phishing website masquerading as the Huawei company career page.

Defensive Architecture Overview

So, how can I defend my organization as effectively as possible from an attack of this type, which involves different techniques and tactics and potential impact? To answer this question, we believe it is necessary to have a multi-layer approach and analyze the various steps, trying to understand the best way to deal with them one by one with an integrated security architecture. Below is a summary of how McAfee’s Security Architecture helps you to protect against the tactics and techniques used in Operation Dianxun.

The goal is to shift-left and block or identify a threat as soon as possible within the Kill Chain to limit any further damage. Shifting-left starts with MVISION Insights, which proactively collects intelligence on the threat and provides details on the indicators of compromise and the MITRE techniques used in the attack. MVISION Insights combines McAfee’s Threat Intelligence research with telemetry from your endpoint controls to reduce your attack surface against emerging threats. MVISION Insights tracks over 800+ Advanced Persistent Threat and Cyber Crime campaigns as researched by McAfee’s ATR team, including Operation Dianxun, sharing a quick summary of the threat, providing external resources, and a list of known indicators such as files, URLs, or IP addresses.

As a threat intelligence analyst or responder, you can drill down into the MVISION Insights interface to gather more specific information on the Operation Dianxun campaign, verify the associated severity, check for geographical prevalence and links to other sources of information. Moreover, MVISION Insights provides useful information like the McAfee products coverage with details of minimum AMCore version; this kind of information is handy to verify actual defensive capabilities within the enterprise and could raise the risk severity in case of weak coverage.

Additional information is available to further investigate on IoCs and MITRE Techniques associated to the campaign. IoCs can be also exported in STIX2 format to be ingested in other tools for automating responses or updating defenses.

The first step ahead of identification is to ensure our architecture can stop or identify the threat in the initial access vector. In this case, the initial delivery vector is a phishing attack so the web channel is therefore fundamental in the initial phase of the infection. McAfee Web Gateway and MVISION UCE provide multi-layer web vector protection with URL Reputation check, SSL decryption, and malware emulation capabilities for analyzing dangerous active Web content.

MVISION UCE also includes the capabilities of Remote Browser Isolation (RBI), the only solution that can provide 100% protection during web browsing. Remote Browser Isolation is indeed an innovative new technology that contains web browsing activity inside an isolated cloud environment in order to protect users from any malware or malicious code that may be hidden on a website. RBI technology provides the most powerful form of web threat protection available, eliminating the opportunity for malicious code to even touch the end user’s device.

The green square around the page means that the web content is isolated by RBI and provided safely through a rendered dynamic visual stream which delivers full browsing experience without risk of infection.

The second phase of exploitation and persistence results from execution on the victim endpoint of Flash-based artifacts malware and, later, DotNet payload. McAfee Endpoint Security running on the target endpoint protects against Operation Dianxun with an array of prevention and detection techniques. ENS Threat Prevention and ATP provides both signature and behavioral analysis capability which proactively detects the threat. ENS also leverages Global Threat Intelligence which is updated with known IoCs. For DAT based detections, the family will be reported as Trojan-Cobalt, Trojan-FSYW, Trojan-FSYX, Trojan-FSZC and CobaltStr-FDWE.

While the execution of the initial fake Flash installer acts mainly like a downloader, the DotNet payload contains several functions and acts as a utility to further compromise the machine. This is a tool to manage and download backdoors to the machine and configure persistence. Thus, the McAfee Endpoint Security Adaptive Threat Protection machine-learning engine triggers detection and blocks execution on its behavior-based analysis.

The last phase of the attack involves creating a backdoor for remote control of the victim via a Command and Control Server and Cobalt Strike Beacon. In this case, in addition to the detection capabilities present at the McAfee Endpoint Security level, detections and blocking features that can be activated on a Next Generation Intrusion Prevention System solution such as McAfee NSP are important. NSP includes a Callback Detection engine and is able to detect and block anomalies in communication signals with C2 Servers.

Investigation and Threat Hunting with MVISION EDR

We demonstrated above how a well defended architecture can thwart and counteract such an attack in each single phase. McAfee Web Gateway and MVISON Unified Cloud Edge can stop the initial entry vector, McAfee Endpoint Protection Platform can block the dropper execution or disrupt the following malicious activities but, only by using MVISION EDR, can you get extensive visibility on the full kill chain.

On MVISION EDR we have the threat detection on the monitoring dashboard for the two different stages and processes of the attack.

Once alerted, the security analyst can dig into the Process Activity and understand behavior and indicators relative to what happened like:

The initial downloader payload flashplayer_install_cn.exe is executed directly by the user and spawned by svchost.exe.

At first it connects back to hxxp://update.flach.cn registering to the c2 and creates a new executable file, flash.exe, in the Windows/temp folder.

Then the sample checks the time and the geolocalization of the infected machine via a request to http://worldclockapi.com.

Next, it connects back to the fake Huawei website “hxxp:\update.careerhuawei.net” used for the initial phishing attack.

Finally, to further completion, you can also use MVISION EDR to search the indicators of compromise in Real-Time or Historically (up to 90 days) across the enterprise systems.

Looking for other systems with evidence of connection to the fake Huawei website:

HostInfo hostname, ip_address and NetworkFlow src_ip, proto, time, process, md5, user where NetworkFlow dst_ip equals “8.210.186.138”

Looking for indicators of the initial downloader payload linked to this campaign.

HostInfo and Files name, full_name, create_user_name, sha1, md5, sha256 where Files sha256 equals “422e3b16e431daa07bae951eed08429a0c4ccf8e37746c733be512f1a5a160a3” or Files sha256 equals “8489ee84e810b5ed337f8496330e69d6840e7c8e228b245f6e28ac6905c19f4a ” or Files sha256 equals “c0331d4dee56ef0a8bb8e3d31bdfd3381bafc6ee80b85b338cee4001f7fb3d8c” or Files sha256 equals “89a1f947b96b39bfd1fffd8d0d670dddd2c4d96f9fdae96f435f2363a483c0e1” or Files sha256 equals “b3fd750484fca838813e814db7d6491fea36abe889787fb7cf3fb29d9d9f5429” or Files sha256 equals “9ccb4ed133be5c9c554027347ad8b722f0b4c3f14bfd947edfe75a015bf085e5” or Files sha256 equals “4e7fc846be8932a9df07f6c5c9cbbd1721620a85c6363f51fa52d8feac68ff47” or Files sha256 equals “0f2e16690fb2ef2b5b4c58b343314fc32603364a312a6b230ab7b4b963160382” or Files sha256 equals “db36ad77875bbf622d96ae8086f44924c37034dd95e9eb6d6369cc6accd2a40d” or Files sha256 equals “8bd55ecb27b94b10cb9b36ab40c7ea954cf602761202546f9b9e163de1dde8eb” or Files sha256 equals “7de56f65ee98a8cd305faefcac66d918565f596405020178aee47a3bd9abd63c” or Files sha256 equals “9d4b4c39106f8e2fd036e798fc67bbd7b98284121724c0f845bca0a6d2ae3999” or Files sha256 equals “ac88a65345b247ea3d0cfb4d2fb1e97afd88460463a4fc5ac25d3569aea42597” or Files sha256 equals “37643f752302a8a3d6bb6cc31f67b8107e6bbbb0e1a725b7cebed2b79812941f” or Files sha256 equals “d0dd9c624bb2b33de96c29b0ccb5aa5b43ce83a54e2842f1643247811487f8d9” or Files sha256 equals “260ebbf392498d00d767a5c5ba695e1a124057c1c01fff2ae76db7853fe4255b” or Files sha256 equals “e784e95fb5b0188f0c7c82add9a3c89c5bc379eaf356a4d3876d9493a986e343” or Files sha256 equals “a95909413a9a72f69d3c102448d37a17659e46630999b25e7f213ec761db9e81” or Files sha256 equals “b7f36159aec7f3512e00bfa8aa189cbb97f9cc4752a635bc272c7a5ac1710e0b” or Files sha256 equals “4332f0740b3b6c7f9b438ef3caa995a40ce53b3348033b381b4ff11b4cae23bd”

Look back historically for domain name resolution and network connection to the involved indicators.

Summary

To defeat targeted threat campaigns like Operation Dianxun, defenders must build an adaptive and integrated security architecture which will make it harder for threat actors to succeed and increase resilience in the business. This blog highlights how to use McAfee’s security solutions to prevent, detect and respond to Operation Dianxun and attackers using similar techniques.

McAfee ATR is actively monitoring this campaign and will continue to update McAfee Insights and its social networking channels with new and current information. Want to stay ahead of the adversaries? Check out McAfee Insights for more information.

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