This report provides detailed analysis of three malicious ISO files associated with a spearphishing campaign using Constant Contact. The files contain a custom …Published on: October 19, 2023. A new and deeply troubling extortion scam has emerged through spam emails, where scammers claim to have infected devices with Cobalt …Richard noted that threat actors shifted away from popular backdoors such as Cobalt Strike Beacon over the last three years. "This likely is related to attackers …Cobalt Strike 4.9 is now available. This release sees an overhaul to Cobalt Strike’s post exploitation capabilities to support user defined reflective loaders (UDRLs), the ability to export Beacon without a reflective loader which adds official support for prepend-style UDRLs, support for callbacks in a number of built-in functions, a new in-Beacon …This is a detection for Cobalt Strike Beacon, which is a software component that gets deployed in target devices and allows an attacker remote access to the device to perform various tasks. What to do now. Guidance for end users. For more tips on how to keep your device safe, ...Jul 8, 2021 · Cobalt Strike and other tools such as Metasploit use a trivial checksum8 algorithm for the request query to distinguish between x86 and x64 payload or beacon. According to leaked Java web server source code, Cobalt Strike uses only two checksum values, 0x5C (92) for x86 payloads and 0x5D for x64 versions. "For example, Cobalt Strike often creates instances of "rundll32.exe" without any command line parameters during process injection, which is an unusual activity. Named pipes are also used for communication between the beacon and spawned processes, where defenders can use Sysmon to detect Cobalt Strike named pipes." Follow The … Cobalt Strike support resources, including the Cobalt Strike Manual, Community Kit, and Technical notes are available to help users. ... Beacon; Interoperablity ... A complementary strategy to the Host Rotation Strategy was introduced to Cobalt Strike 4.5. The max retry strategy was added to HTTP, HTTPS, and DNS beacon listeners. A max retry strategy allows a beacon to exit after a specified failure count. As the failure count increases, sleep is adjusted to a specified value. By default, sleep is …DNS - using a variety of DNS queries, Cobalt Strike's beacons can communicate back to the C2 server using only DNS. The advantage is that name resolution is almost always allowed and no direct communication takes place between the implant and the C2 server, since the DNS resolution will happen using the default nameservers. ...May 11, 2020 · Key Points. 1. Progression: The attack propogated initially through the company’s VPN to an inner Windows server, and then on to the Domain Controller and afterward to servers containing the sought-after data. 2. Toolkit: The attackers used a CobaltStrike beacon with a then-unknown persistence method using DLL hijacking (detailed below). Jun 15, 2022 · Extract the package on the Windows endpoint (Password: apt). Start cmd.exe as Administrator. Navigate to the extracted program folder and run APTSimulator.bat. Once APTSimulator.bat is running, choose “CobaltStrike Beacon Simulation” and let it run. This would generate Cobalt Strike beacon activity. A key part of Cobalt Strike is the Beacon, a piece of software injected into the target computer to create a secret communication channel that enables the Cobalt …Cobalt Strike is commercial threat emulation software that emulates a quiet, long-term embedded actor in a network. This actor, known as Beacon, communicates …Sep 30, 2022 · A social engineering campaign leveraging job-themed lures is weaponizing a years-old remote code execution flaw in Microsoft Office to deploy Cobalt Strike beacons on compromised hosts. "The payload discovered is a leaked version of a Cobalt Strike beacon," Cisco Talos researchers Chetan Raghuprasad and Vanja Svajcer said in a new analysis ... Cobalt Strike’s ‘Beacon’ payload is a particularly dangerous aspect of the tool. Once deployed, it allows attackers to maintain a discreet presence within a network, carrying out operations while remaining largely invisible to security systems. This facilitates long-term data theft, manipulation, and disruption of network operations.Before Cobalt Strike 2.0, there were ways to deliver Beacon with Veil. Cobalt Strike’s Beacon is compatible with the Metasploit Framework’s reverse_http and reverse_https stagers. You had the option to use the Metasploit Framework’s stagers to deliver Beacon. That said, Cobalt Strike’s Beacon has its own stagers that are not …Beacon’s spawn and inject commands are designed to pass sessions via stagers. It’s possible to pass sessions in Cobalt Strike without staging. Go to Attacks -> Packages -> Windows EXE (S) and export a raw stageless payload artifact. This file is essentially a large-blob of shellcode that contains the Beacon payload.Mar 16, 2022 · Cobalt Strike is commercial threat emulation software that emulates a quiet, long-term embedded actor in a network. This actor, known as Beacon, communicates with an external team server to emulate command and control (C2) traffic. Due to its versatility, Cobalt Strike is commonly used as a legitimate tool by red teams – but is also widely ... Cobalt Strike. Cobalt Strike is a commercial, full-featured, remote access tool that bills itself as "adversary simulation software designed to execute targeted attacks and emulate the post-exploitation actions of advanced threat actors". Cobalt Strike’s interactive post-exploit capabilities cover the full range of ATT&CK tactics, all ... Cobalt Strike 's Beacon has a protocol to accept artifact-provided function pointers for functions required by Beacon's Reflective Loader. The protocol is to patch the location of GetProcAddress and GetModuleHandleA into the Beacon DLL. Use of this protocol allows Beacon to load itself in memory without triggering shellcode detection heuristics ...Jan 20, 2021 · In our investigations, we came across additional custom loaders for Cobalt Strike’s Beacon that appear to be generated using custom Cobalt Strike Artifact Kit templates. Unlike TEARDROP, in which the malicious code is triggered by an export function, the malicious code in these variants is triggered directly from the DLL’s entry point ... SentinelOne discovered a denial of service (DoS) vulnerability in Cobalt Strike. The bug (aka Hotcobalt) can cause a denial of service on a teamserver by using a fake beacon sending abnormally large screenshots.. This bug has been fixed in Cobalt Strike 4.4. Consider mitigating this risk to a teamserver by hardening your C2 infrastructure. Redefine Beacon's communication with Cobalt Strike's malleable C2 language. This allows you to cloak Beacon activity to look like other malware or blend-in as legitimate traffic. The Beacon Console. Right-click on a Beacon session and select interact to open that Beacon’s console. The console is the main user interface for your Beacon session. Cobalt Strike, though, hides shellcode over a named pipe. ... The Malleable C2 module in Cobalt Strike is an advanced tool that allows attackers to customize beacon traffic and create covert ...Cobalt Strike is commercial threat emulation software that emulates a quiet, long-term embedded actor in a network. This actor, known as Beacon, communicates …The Cobalt Strike team server has no remote attacks or built-in offensive capability [with the exception of spear phishing]. Instead, Cobalt Strike pushes all of its offensive actions down to the Beacon payload. The Beacon payload then executes these things on your behalf. This method of offense plays well with asynchronous communication.It is time to test how well the beacon will perform against static signature scanners. Enabling the following feature will remove most of the strings stored in the beacon’s heap: set obfuscate "true"; Once the profile is applied to Cobalt Strike, generate a raw shellcode and put it in the Shellcode loader’s code. Once the EXE was compiled ...The Cobalt Strike beacon allows the threat actors to execute commands remotely on the infected device, allowing threat actors to steal data or spread laterally through the compromised network.A complementary strategy to the Host Rotation Strategy was introduced to Cobalt Strike 4.5. The max retry strategy was added to HTTP, HTTPS, and DNS beacon listeners. A max retry strategy allows a beacon to exit after a specified failure count. As the failure count increases, sleep is adjusted to a specified value. By default, sleep is …Jan 12, 2023 · Virus check your devices using Norton Power Eraser if applicable or any of the antivirus checks that Norton supply for mobile devices. Do search for topics such as Cobalt Strike "Beacon". When I did this I saw a response by a Microsoft independent advisor who advised steps such as scanning devices and reporting the originator of the message. Mar 16, 2022 · Cobalt Strike is commercial threat emulation software that emulates a quiet, long-term embedded actor in a network. This actor, known as Beacon, communicates with an external team server to emulate command and control (C2) traffic. Due to its versatility, Cobalt Strike is commonly used as a legitimate tool by red teams – but is also widely ... Running Commands. Beacon’s shell command will task a Beacon to execute a command via cmd.exe on the compromised host.When the command completes, Beacon will present the output to you. Use the run command to execute a command without cmd.exe.The run command will post output to you. The execute command runs a program in the …If a Cobalt Strike beacon is returned, we store the data ready for ingest into our database. Figure 2 Example of an extracted Cobalt Strike beacon. Now that we have discussed a methodology to identify Cobalt Strike Team Servers and carve out beacon configs, we need somewhere to ingest the data to begin hunting. ...Cobalt Strike 4.9 is now available. This release sees an overhaul to Cobalt Strike’s post exploitation capabilities to support user defined reflective loaders (UDRLs), the ability to export Beacon without a reflective loader which adds official support for prepend-style UDRLs, support for callbacks in a number of built-in functions, a new in-Beacon …Small stagers embed well into Cobalt Strike’s built-in attack packages. Small stagers also allow me to use a PowerShell one-liner, during lateral movement, to bootstrap a payload into memory without putting a binary on disk. One of my favorite Cobalt Strike demos is the one where I embed a DNS TXT record stager for Beacon into a …Cobalt Strike ’s phishing tool repurposes saved emails into pixel- perfect phishes. Control your target’s network with Cobalt Strike ’s Beacon. This post-exploitation payload uses an asynchronous “low and slow” communication pattern that’s common with advanced threat malware. Beacon will phone home over DNS, HTTP, or HTTPS.Ryan Stephenson (RCStep) Adds Shellcode - Shellcode Generator to the Cobalt Strike top menu bar. CSSG is aggressor, .NET, and python scripts used to more easily generate and format beacon shellcode. Generates beacon stageless shellcode with exposed exit method, additional formatting, encryption, encoding, compression, multiline output, etc.Cobalt Strike Beacon is a signature payload that can gain and maintain control of compromised systems during adversary simulations and red team engagements. It can …With the ability to steal a specific one by using BeaconUseToken(HANDLE token) Cobalt Strike Beacon API. This is great but I wanted to keep track of the … Redefine Beacon's communication with Cobalt Strike's malleable C2 language. This allows you to cloak Beacon activity to look like other malware or blend-in as legitimate traffic. The Beacon Console. Right-click on a Beacon session and select interact to open that Beacon’s console. The console is the main user interface for your Beacon session. May 16, 2023. 08:10 AM. 2. Geacon, a Go-based implementation of the beacon from the widely abused penetration testing suite Cobalt Strike, is being used more and more to target macOS devices. Both ...A tool to hunt/mine for Cobalt Strike beacons and "reduce" their beacon configuration for later indexing. Hunts can either be expansive and internet wide using services like SecurityTrails, Shodan, or ZoomEye or a list of IP's. Getting started. Install melting-cobalt;Cobalt Strike "Beacon" : PHISHING OR EXTORTION ? I have multiple email addresses for miscellaneous purposes, and I did not receive other threats on these emails, at least for now if true. DE: withheld @479644105645826333.com. Objet : Payment Report - 224145-1380-*. À : withheld.When you have a full system memory dump that is uncompressed, the first thing to check, is for the presence of a Cobalt Strike beacon in memory. This can be done with tool 1768.py, a tool to extract and analyze the configuration of Cobalt Strike beacons. Make sure to use a 64-bit version of Python, as uncompressed full memory dumps are …In a sample of the Cobalt Strike beacon shared with BleepingComputer, the malware will communicate with the attacker's command and control servers through a fake 'jquery-3.3.1.min.js' file.The UDRL is an important aspect of Cobalt Strike’s evasion strategy. Cobalt Strike achieves “evasion through flexibility”, meaning we give you the tools you need to modify default behaviors and customize Beacon to your liking. This was something that Raphael Mudge felt strongly about and will remain a key part of the Cobalt Strike ...These beacons send data back with an HTTP POST request. This is the default. You have incredible control over the behavior and indicators in this payload via Malleable C2. HTTP(S) Listener Setup. To create a HTTP or HTTPS Beacon listener select Cobalt Strike-> Listeners on the main menu and press the Add button at the bottom of the …A tool to hunt/mine for Cobalt Strike beacons and "reduce" their beacon configuration for later indexing. Hunts can either be expansive and internet wide using services like SecurityTrails, Shodan, or ZoomEye or a list of IP's. Getting started. Install melting-cobalt;Pelaku ancaman mengimplementasikan ulang Cobalt Strike Beacon versi Linux dan Windows tidak resmi dari awal dan secara aktif menggunakannya dalam serangan yang ditujukan untuk organisasi di seluruh dunia. Versi Linux dari alat pasca-eksploitasi komersial diberi nama kode Vermilion Strike dan menurut peneliti Intezer, yang melihatnya, apakah ...Learn how to identify and detect adversary activities using Cobalt Strike's Beacon client agent, a tool for post-exploitation and red team operations. The blog explains the behavior, commands, and …Also, a Cobalt Strike beacon can execute PowerShell scripts, perform keylogging activities, take screenshots, download files, and spawn other payloads. Ways Cobalt Strike Can Help Security Researchers It is often difficult to spot gaps or vulnerabilities in a system that you created or have been using for a long time. By using …How it works. BeaconEye will scan live processes or MiniDump files for suspected CobaltStrike beacons. In live process mode, BeaconEye optionally attaches itself as a debugger and will begin monitoring beacon activity for C2 traffic (HTTP/HTTPS beacons supported currently). The AES keys used for encrypting C2 data and mallable profile are ...Cobalt Strike is popular with threat actors since it's easy to deploy and use, plus its ability to avoid detection. ... The main payload of Cobalt Strike is called “Beacon.” The Beacon payload is used to model advanced APT malware, and can do the following: Receive commands (either passively or from an interactive console) Egress ...Nov 28, 2022 · Google’s rules include 165 signatures covering 34 different Cobalt Strike versions, each with 10 to 100 attack templates and typically unique Beacon components. Who uses Cobalt Strike? While ... Mar 13, 2022 · Community+ 2024. Level 10. 183,570 points. Posted on Mar 13, 2022 8:00 PM. MediOgre wrote: I was recently contacted by someone via email saying they had installed a Cobalt Strike Beacon on my devices and is threatening to release a bunch of information to my email contacts. I have done an Etrecheck scan and cannot interpret anything of importance. Cobalt Strike arsenal. Modify the Artifact Kit, the is a source code framework used to generate executables and DLLs or redefine the script templates located in the Resource Kit, which Cobalt Strike uses in its workflows. Finally, you can write your own Beacon Object File (BOF) and expand the Beacon agent with post-exploitation features.Oct 19, 2023 · The Cobalt Strike Beacon scam email utilizes various sophisticated social engineering and pressure tactics to manipulate and deceive victims. Here is how it operates, step-by-step: The email will have an alarming or urgent subject line designed specifically to entice opening and reading. Beacon Object Files (BOFs) were introduced in Cobalt Strike 4.1 in 2020. Since their release, BOFs have played a key role in post-exploitation activities, surpassing Reflective DLLs, .NET assemblies, and PowerShell scripts. However, in our experience, many developers struggle with four primary pain points: The limitations of writing BOFs in CNamed pipes are essential for the operation of Cobalt Strike beacons. Before version 4.2, Cobalt Strike did not allow the operators to change the default naming scheme of named pipes. If Sysmon is deployed in the environment and correctly configured, then it is an opportunity to detect Cobalt Strike’s default named pipes.Threat Spotlight Cobalt Strike. Cisco Talos discovered a malicious campaign in August 2022 delivering Cobalt Strike beacons that could be used in later, follow-on attacks. Lure themes in the phishing documents in this campaign are related to the job details of a government organization in the United States and a trade union in …This post, from Ernesto Alvarez Capandeguy of Core Security’s CoreLabs Research Team, describes techniques used for creating UDP redirectors for protecting Cobalt Strike team servers. This is one of the recommended mechanisms for hiding Cobalt Strike team servers and involves adding different points which a Beacon can contact for …Jun 1, 2021 · Cobalt Strike Beacon provides encrypted communication with the C&C server to send information and receive commands. Those commands can include instructions to download malware. After doing this, they can use Cobalt Strike to map out the network and identify any vulnerabilities as well as deploy implants, backdoors, and other tools to accomplish ... Assumption is the key word. Malleable C2 gives operators a lot of power to change what Cobalt Strike’s HTTP communication looks like. Malleable C2 is an example of a declarative programming language. You, the operator, specify what Beacon’s communication should look like. Cobalt Strike figures out how to make that happen. …For each release version of Cobalt Strike, we found that a new, unique beacon component is usually created. The stagers and templates, however, tend to be more constant across versions. Looking for unique stagers, templates, and beacons across the different versions, a total of 165 signatures were generated to detect these Cobalt …Last updated April 19, 2024 Views 72,356 Applies to: Windows. /. Windows 11. /. Security and privacy. I received an email today, stating that someone or group had …In Cobalt Strike 4.0 and later, the DNS Beacon is a DNS-only payload. There is no HTTP communication mode in this payload. This is a change from prior versions of the product. Data Channels. Today, the DNS Beacon can download tasks over DNS TXT records, DNS AAAA records, or DNS A records. This payload has the flexibility to change between …Cobalt Strike Beacon used by NOBELIUM; Cobalt Strike network infrastructure used by NOBELIUM; The following alerts might also indicate threat activity associated with this threat. These alerts, however, can be triggered by unrelated threat activity and are not monitored in the status cards provided with this report.Cobalt Strike is a popular command and control (C2) framework used by cybercriminals to drop multiple payloads after profiling a compromised network. Learn …May 16, 2019 · This is a detection for Cobalt Strike Beacon, which is a software component that gets deployed in target devices and allows an attacker remote access to the device to perform various tasks. Beacon; Interoperablity; Community. All Features > Footer Menu 2. Interoperability. Core Impact; Outflank Security Tooling; Footer Menu 3. Support. Training; Community Kit; ... Cobalt Strike support resources, including the Cobalt Strike Manual, Community Kit, and Technical notes are available to help users.Cobalt Strike Introduction. This 40 minute on-demand Cobalt Strike demonstration includes a guided walkthrough in a small cyber range to help demonstrate the key features of the solution. The focus is not on understanding all the security topics mentioned in detail, but rather to explore Cobalt Strike’s capabilities.Cobalt Strike is popular with threat actors since it's easy to deploy and use, plus its ability to avoid detection. ... The main payload of Cobalt Strike is called “Beacon.” The Beacon payload is used to model advanced APT malware, and can do the following: Receive commands (either passively or from an interactive console) Egress ...A complementary strategy to the Host Rotation Strategy was introduced to Cobalt Strike 4.5. The max retry strategy was added to HTTP, HTTPS, and DNS beacon listeners. A max retry strategy allows a beacon to exit after a specified failure count. As the failure count increases, sleep is adjusted to a specified value. By default, sleep is …In a sample of the Cobalt Strike beacon shared with BleepingComputer, the malware will communicate with the attacker's command and control servers through a fake 'jquery-3.3.1.min.js' file.Nov 28, 2022 · Google’s rules include 165 signatures covering 34 different Cobalt Strike versions, each with 10 to 100 attack templates and typically unique Beacon components. Who uses Cobalt Strike? While ... Parses beacon's configuration from beacon PE or memory dump. Returns json of config is found; else it returns None. :int version: Try a specific version (3 or 4), or leave None to try both of themMar 13, 2022 · Community+ 2024. Level 10. 183,570 points. Posted on Mar 13, 2022 8:00 PM. MediOgre wrote: I was recently contacted by someone via email saying they had installed a Cobalt Strike Beacon on my devices and is threatening to release a bunch of information to my email contacts. I have done an Etrecheck scan and cannot interpret anything of importance. When Beacon starts, it resolves metadata to send back to Cobalt Strike. Previously, Beacon stuck out like a sore thumb in mature environments since the method used to resolve this metadata triggered Sysmon event 22 (DNS Query) and had become a way to reliably fingerprint Beacon every time it runs. The 4.4 release modifies how this …Jun 30, 2021 · Cobalt Strike [1] is a tool to support red teams in attack simulation exercises. To this end, Cobalt Strike provides several techniques that allow a red team to execute targeted attacks to compromise a target network, established a bridge head on a host, and then move laterally to gain additional access to computers, accounts, and, eventually, data. Dec 6, 2022 · KoboldLoader runs the payload using mapping injection and launches a decrypted Cobalt Strike SMB beacon that can be detected in memory, despite some in-memory evasion features. It would have been impossible to detect the SMB beacon without being able to look inside memory while the malicious code was being executed, according to the researchers. Cobalt Strike 4.7 is now available. This release sees support for SOCKS5, new options to provide flexibility around how BOFs live in memory, updates to how Beacon sleeps and a number of other changes that have been requested by our users. We’ve also given the user interface a bit of a refresh (including support for the much-requested dark …
Cobalt Strike has a client-server architecture, in which several users (e.g., the members of the red team performing the attack) connect to a Team Server using the Aggressor client application. ... One of the most important components of the Cobalt Strike framework is the Beacon component. This component is installed on a host as part of …. How do i block youtube
Mar 16, 2022 · Cobalt Strike is commercial threat emulation software that emulates a quiet, long-term embedded actor in a network. This actor, known as Beacon, communicates with an external team server to emulate command and control (C2) traffic. Due to its versatility, Cobalt Strike is commonly used as a legitimate tool by red teams – but is also widely ... A new malware campaign uses the lure of a job to infect victims with leaked versions of Cobalt Strike beacons. Researchers with Cisco Talos said the attack begins with phishing emails regarding fraudulent job opportunities with either the U.S. government or a trade union in New Zealand. Ironically, one of the lures is for a job in the U.S. …Cobalt Strike is highly configurable, but many actors use default settings, such as SSL certs, Beacon URLs, and profiles that offer defenders detection opportunities. Advanced threat actors will customize Cobalt Strike payloads to avoid detection better using built-in tools like Artifact Kit, Malleable C2 Profiles, and Resource Kit.Thursday 05 March, 2015. One common Cobalt Strike feature request is an API to script the Beacon payload. Doing this right is a big project and it requires some architectural changes within Cobalt Strike. I’m working on it. I have a major development effort underway to reshape Beacon’s role in Cobalt Strike. Scripting is one piece of this.Assumption is the key word. Malleable C2 gives operators a lot of power to change what Cobalt Strike’s HTTP communication looks like. Malleable C2 is an example of a declarative programming language. You, the operator, specify what Beacon’s communication should look like. Cobalt Strike figures out how to make that happen. …Cobalt Strike’s Beacon exposes a SOCKS interface for pivoting. SOCKS is a standard for proxy servers and proxy-aware clients. To create a SOCKS interface tied to a Beacon: 1. Interact with a Beacon. 2. Type sleep 0 to ask to the Beacon to check-in multiple times each second. A high check-in time will introduce latency into your tunneled …May 28, 2021 · This report provides detailed analysis of three malicious ISO files associated with a spearphishing campaign using Constant Contact. The files contain a custom Cobalt Strike Beacon loader, a decoy PDF, and a shortcut that executes the beacon on a compromised system. Cobalt Strike is an adversary simulation software designed to test IT infrastructure for resilience against advanced cyberattacks. The technology emulates realistic threats in live attacks, enabling organizations to assess their vulnerabilities and better protect themselves. However, Cobalt Strike can also introduce risk: due to its various ... Many of Cobalt Strike’s attacks and workflows deliver a payload as multiple stages. The first stage is called a stager. The stager is a very tiny program, often written in hand-optimized assembly, that: connects to Cobalt Strike, downloads the Beacon payload (also called the stage), and executes it. The payload staging process exists for a ...What Is a Cobalt Strike Beacon? Cobalt Strike can generate remote agents known as beacons that can be deployed to achieve remote code execution (RCE) on the target system once initial access has been gained. Beacons are configured to conduct further malicious activities with custom settings and are deployed as either “staged” or ...Beacon is Cobalt Strike’s payload to model advanced attackers. Use Beacon to egress a network over HTTP, HTTPS, or DNS. You may also limit which hosts egress a network by controlling peer- to-peer Beacons over Windows named pipes and TCP sockets. Beacon is flexible and supports asynchronous and interactive communication.Cobalt Strike is a popular red team tool for Windows which is also heavily used by threat actors. At the time of this writing, there is no official Cobalt Strike version for Linux. In August 2021, we at Intezer discovered a fully undetected ELF implementation of Cobalt Strike’s beacon, which we named Vermilion Strike.Cobalt Strike is a threat emulation tool which simulates adversarial post-exploitation scenarios and supports Red Team operations. Replicate the tactics of a long-term embedded threat actor using a post-exploitation agent, Beacon, and Malleable C2, a command and control program that enables modification of network indicators to blend in …It is often difficult to collect the Cobalt Strike beacon payload from memory and extract its configuration to identify observables and cluster group activities, partially due to the tremendous amount of metadata the beacon’s configurations include. The early stages of an intrusion usually include initial access, execution, persistence, and ...Nov 18, 2020 · Cobalt Strike, though, hides shellcode over a named pipe. ... The Malleable C2 module in Cobalt Strike is an advanced tool that allows attackers to customize beacon traffic and create covert ... .