Group Elderwood

Elderwood is a suspected Chinese cyber espionage group that was reportedly responsible for the 2009 Google intrusion known as Operation Aurora. The group has targeted defense organizations, supply chain manufacturers, human rights and nongovernmental organizations (NGOs), and IT service providers.

List of techniques used :

id	description
T1027.002	Obfuscated Files or Information: Software Packing Adversaries may perform software packing or virtual machine software protection to conceal their code. Software packing is a method of compressing or encrypting an executable. Packing an executable changes the file signature in an attempt to avoid signature-based detection. Most decompression techniques decompress the executable code in memory. Virtual machine software protection translates an executable's original code into a special format that only a special virtual machine can run. A virtual machine is then called to run this code. Utilities used to perform software packing are called packers. Example packers are MPRESS and UPX. A more comprehensive list of known packers is available, but adversaries may create their own packing techniques that do not leave the same artifacts as well-known packers to evade defenses.
T1027.013	Obfuscated Files or Information: Encrypted/Encoded File Adversaries may encrypt or encode files to obfuscate strings, bytes, and other specific patterns to impede detection. Encrypting and/or encoding file content aims to conceal malicious artifacts within a file used in an intrusion. Many other techniques, such as Software Packing, Steganography, and Embedded Payloads, share this same broad objective. Encrypting and/or encoding files could lead to a lapse in detection of static signatures, only for this malicious content to be revealed (i.e., Deobfuscate/Decode Files or Information) at the time of execution/use. This type of file obfuscation can be applied to many file artifacts present on victim hosts, such as malware log/configuration and payload files. Files can be encrypted with a hardcoded or user-supplied key, as well as otherwise obfuscated using standard encoding/compression schemes such as Base64. The entire content of a file may be obfuscated, or just specific functions or values (such as C2 addresses). Encryption and encoding may also be applied in redundant layers for additional protection. For example, adversaries may abuse password-protected Word documents or self-extracting (SFX) archives as a method of encrypting/encoding a file such as a Phishing payload. These files typically function by attaching the intended archived content to a decompressor stub that is executed when the file is invoked (e.g., User Execution). Adversaries may also abuse file-specific as well as custom encoding schemes. For example, Byte Order Mark (BOM) headers in text files may be abused to manipulate and obfuscate file content until Command and Scripting Interpreter execution.
T1105	Ingress Tool Transfer Adversaries may transfer tools or other files from an external system into a compromised environment. Tools or files may be copied from an external adversary-controlled system to the victim network through the command and control channel or through alternate protocols such as ftp. Once present, adversaries may also transfer/spread tools between victim devices within a compromised environment (i.e. Lateral Tool Transfer). On Windows, adversaries may use various utilities to download tools, such as `copy`, `finger`, certutil, and PowerShell commands such as IEX(New-Object Net.WebClient).downloadString() and Invoke-WebRequest. On Linux and macOS systems, a variety of utilities also exist, such as `curl`, `scp`, `sftp`, `tftp`, `rsync`, `finger`, and `wget`. Adversaries may also abuse installers and package managers, such as `yum` or `winget`, to download tools to victim hosts. Adversaries have also abused file application features, such as the Windows `search-ms` protocol handler, to deliver malicious files to victims through remote file searches invoked by User Execution (typically after interacting with Phishing lures). Files can also be transferred using various Web Services as well as native or otherwise present tools on the victim system. In some cases, adversaries may be able to leverage services that sync between a web-based and an on-premises client, such as Dropbox or OneDrive, to transfer files onto victim systems. For example, by compromising a cloud account and logging into the service's web portal, an adversary may be able to trigger an automatic syncing process that transfers the file onto the victim's machine.
T1189	Drive-by Compromise Adversaries may gain access to a system through a user visiting a website over the normal course of browsing. With this technique, the user's web browser is typically targeted for exploitation, but adversaries may also use compromised websites for non-exploitation behavior such as acquiring Application Access Token. Multiple ways of delivering exploit code to a browser exist (i.e., Drive-by Target), including: * A legitimate website is compromised where adversaries have injected some form of malicious code such as JavaScript, iFrames, and cross-site scripting * Script files served to a legitimate website from a publicly writeable cloud storage bucket are modified by an adversary * Malicious ads are paid for and served through legitimate ad providers (i.e., Malvertising) * Built-in web application interfaces are leveraged for the insertion of any other kind of object that can be used to display web content or contain a script that executes on the visiting client (e.g. forum posts, comments, and other user controllable web content). Often the website used by an adversary is one visited by a specific community, such as government, a particular industry, or region, where the goal is to compromise a specific user or set of users based on a shared interest. This kind of targeted campaign is often referred to a strategic web compromise or watering hole attack. There are several known examples of this occurring. Typical drive-by compromise process: 1. A user visits a website that is used to host the adversary controlled content. 2. Scripts automatically execute, typically searching versions of the browser and plugins for a potentially vulnerable version. * The user may be required to assist in this process by enabling scripting or active website components and ignoring warning dialog boxes. 3. Upon finding a vulnerable version, exploit code is delivered to the browser. 4. If exploitation is successful, then it will give the adversary code execution on the user's system unless other protections are in place. * In some cases a second visit to the website after the initial scan is required before exploit code is delivered. Unlike Exploit Public-Facing Application, the focus of this technique is to exploit software on a client endpoint upon visiting a website. This will commonly give an adversary access to systems on the internal network instead of external systems that may be in a DMZ. Adversaries may also use compromised websites to deliver a user to a malicious application designed to Steal Application Access Tokens, like OAuth tokens, to gain access to protected applications and information. These malicious applications have been delivered through popups on legitimate websites.
T1203	Exploitation for Client Execution Adversaries may exploit software vulnerabilities in client applications to execute code. Vulnerabilities can exist in software due to unsecure coding practices that can lead to unanticipated behavior. Adversaries can take advantage of certain vulnerabilities through targeted exploitation for the purpose of arbitrary code execution. Oftentimes the most valuable exploits to an offensive toolkit are those that can be used to obtain code execution on a remote system because they can be used to gain access to that system. Users will expect to see files related to the applications they commonly used to do work, so they are a useful target for exploit research and development because of their high utility. Several types exist: ### Browser-based Exploitation Web browsers are a common target through Drive-by Compromise and Spearphishing Link. Endpoint systems may be compromised through normal web browsing or from certain users being targeted by links in spearphishing emails to adversary controlled sites used to exploit the web browser. These often do not require an action by the user for the exploit to be executed. ### Office Applications Common office and productivity applications such as Microsoft Office are also targeted through Phishing. Malicious files will be transmitted directly as attachments or through links to download them. These require the user to open the document or file for the exploit to run. ### Common Third-party Applications Other applications that are commonly seen or are part of the software deployed in a target network may also be used for exploitation. Applications such as Adobe Reader and Flash, which are common in enterprise environments, have been routinely targeted by adversaries attempting to gain access to systems. Depending on the software and nature of the vulnerability, some may be exploited in the browser or require the user to open a file. For instance, some Flash exploits have been delivered as objects within Microsoft Office documents.
T1204.001	User Execution: Malicious Link An adversary may rely upon a user clicking a malicious link in order to gain execution. Users may be subjected to social engineering to get them to click on a link that will lead to code execution. This user action will typically be observed as follow-on behavior from Spearphishing Link. Clicking on a link may also lead to other execution techniques such as exploitation of a browser or application vulnerability via Exploitation for Client Execution. Links may also lead users to download files that require execution via Malicious File.
T1204.002	User Execution: Malicious File An adversary may rely upon a user opening a malicious file in order to gain execution. Users may be subjected to social engineering to get them to open a file that will lead to code execution. This user action will typically be observed as follow-on behavior from Spearphishing Attachment. Adversaries may use several types of files that require a user to execute them, including .doc, .pdf, .xls, .rtf, .scr, .exe, .lnk, .pif, .cpl, and .reg. Adversaries may employ various forms of Masquerading and Obfuscated Files or Information to increase the likelihood that a user will open and successfully execute a malicious file. These methods may include using a familiar naming convention and/or password protecting the file and supplying instructions to a user on how to open it. While Malicious File frequently occurs shortly after Initial Access it may occur at other phases of an intrusion, such as when an adversary places a file in a shared directory or on a user's desktop hoping that a user will click on it. This activity may also be seen shortly after Internal Spearphishing.
T1566.001	Phishing: Spearphishing Attachment Adversaries may send spearphishing emails with a malicious attachment in an attempt to gain access to victim systems. Spearphishing attachment is a specific variant of spearphishing. Spearphishing attachment is different from other forms of spearphishing in that it employs the use of malware attached to an email. All forms of spearphishing are electronically delivered social engineering targeted at a specific individual, company, or industry. In this scenario, adversaries attach a file to the spearphishing email and usually rely upon User Execution to gain execution. Spearphishing may also involve social engineering techniques, such as posing as a trusted source. There are many options for the attachment such as Microsoft Office documents, executables, PDFs, or archived files. Upon opening the attachment (and potentially clicking past protections), the adversary's payload exploits a vulnerability or directly executes on the user's system. The text of the spearphishing email usually tries to give a plausible reason why the file should be opened, and may explain how to bypass system protections in order to do so. The email may also contain instructions on how to decrypt an attachment, such as a zip file password, in order to evade email boundary defenses. Adversaries frequently manipulate file extensions and icons in order to make attached executables appear to be document files, or files exploiting one application appear to be a file for a different one.
T1566.002	Phishing: Spearphishing Link Adversaries may send spearphishing emails with a malicious link in an attempt to gain access to victim systems. Spearphishing with a link is a specific variant of spearphishing. It is different from other forms of spearphishing in that it employs the use of links to download malware contained in email, instead of attaching malicious files to the email itself, to avoid defenses that may inspect email attachments. Spearphishing may also involve social engineering techniques, such as posing as a trusted source. All forms of spearphishing are electronically delivered social engineering targeted at a specific individual, company, or industry. In this case, the malicious emails contain links. Generally, the links will be accompanied by social engineering text and require the user to actively click or copy and paste a URL into a browser, leveraging User Execution. The visited website may compromise the web browser using an exploit, or the user will be prompted to download applications, documents, zip files, or even executables depending on the pretext for the email in the first place. Adversaries may also include links that are intended to interact directly with an email reader, including embedded images intended to exploit the end system directly. Additionally, adversaries may use seemingly benign links that abuse special characters to mimic legitimate websites (known as an "IDN homograph attack"). URLs may also be obfuscated by taking advantage of quirks in the URL schema, such as the acceptance of integer- or hexadecimal-based hostname formats and the automatic discarding of text before an “@” symbol: for example, `hxxp://google.com@1157586937`. Adversaries may also utilize links to perform consent phishing, typically with OAuth 2.0 request URLs that when accepted by the user provide permissions/access for malicious applications, allowing adversaries to Steal Application Access Tokens. These stolen access tokens allow the adversary to perform various actions on behalf of the user via API calls. Adversaries may also utilize spearphishing links to Steal Application Access Tokens that grant immediate access to the victim environment. For example, a user may be lured through “consent phishing” into granting adversaries permissions/access via a malicious OAuth 2.0 request URL . Similarly, malicious links may also target device-based authorization, such as OAuth 2.0 device authorization grant flow which is typically used to authenticate devices without UIs/browsers. Known as “device code phishing,” an adversary may send a link that directs the victim to a malicious authorization page where the user is tricked into entering a code/credentials that produces a device token.