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Ballistic Bobcat’s scan and strike backdoor

ESET researchers found a Ballistic Bobcat marketing campaign concentrating on numerous entities in Brazil, Israel, and the United Arab Emirates, utilizing a novel backdoor we now have named Sponsor.

We found Sponsor after we analyzed an fascinating pattern we detected on a sufferer’s system in Israel in Could 2022 and scoped the victim-set by nation. Upon examination, it grew to become evident to us that the pattern was a novel backdoor deployed by the Ballistic Bobcat APT group.

Ballistic Bobcat, beforehand tracked by ESET Analysis as APT35/APT42 (aka Charming Kitten, TA453, or PHOSPHORUS), is a suspected Iran-aligned superior persistent risk group that targets training, authorities, and healthcare organizations, in addition to human rights activists and journalists. It’s most energetic in Israel, the Center East, and the US. Notably, in the course of the pandemic, it was concentrating on COVID-19-related organizations, together with the World Well being Group and Gilead Prescribed drugs, and medical analysis personnel.

Overlaps between Ballistic Bobcat campaigns and Sponsor backdoor variations present a reasonably clear sample of software improvement and deployment, with narrowly focused campaigns, every of restricted period. We subsequently found 4 different variations of the Sponsor backdoor. In whole, we noticed Sponsor deployed to not less than 34 victims in Brazil, Israel, and the United Arab Emirates, as outlined in Determine 1.

Figure 1. Timeline of the Sponsoring Access campaign
Determine 1. Timeline of the Sponsoring Entry marketing campaign

Key factors of this blogpost:

  • We found a brand new backdoor deployed by Ballistic Bobcat that we subsequently named Sponsor.
  • Ballistic Bobcat deployed the brand new backdoor in September 2021, whereas it was wrapping up the marketing campaign documented in CISA Alert AA21-321A and the PowerLess marketing campaign.
  • The Sponsor backdoor makes use of configuration recordsdata saved on disk. These recordsdata are discreetly deployed by batch recordsdata and intentionally designed to seem innocuous, thereby trying to evade detection by scanning engines.
  • Sponsor was deployed to not less than 34 victims in Brazil, Israel, and the United Arab Emirates; we now have named this exercise the Sponsoring Entry marketing campaign.

Preliminary entry

Ballistic Bobcat obtained preliminary entry by exploiting identified vulnerabilities in internet-exposed Microsoft Alternate servers by first conducting meticulous scans of the system or community to establish potential weaknesses or vulnerabilities, and subsequently concentrating on and exploiting these recognized weaknesses. The group has been identified to interact on this habits for a while. Nevertheless, most of the 34 victims recognized in ESET telemetry would possibly greatest be described as victims of alternative quite than preselected and researched victims, as we suspect Ballistic Bobcat engaged within the above-described scan-and-exploit habits as a result of it was not the one risk actor with entry to those techniques. We’ve named this Ballistic Bobcat exercise using the Sponsor backdoor the Sponsoring Entry marketing campaign.

The Sponsor backdoor makes use of configuration recordsdata on disk, dropped by batch recordsdata, and each are innocuous in order to bypass scanning engines. This modular method is one which Ballistic Bobcat has used very often and with modest success up to now two and a half years. On compromised techniques, Ballistic Bobcat additionally continues to make use of quite a lot of open-source instruments, which we describe – along with the Sponsor backdoor – on this blogpost.


Figure 2. Geographical distribution of entities targeted by Ballistic Bobcat with the Sponsor backdoor
Determine 2. Geographical distribution of entities focused by Ballistic Bobcat with the Sponsor backdoor

A big majority of the 34 victims have been positioned in Israel, with solely two positioned in different international locations:

  • Brazil, at a medical cooperative and medical insurance operator, and
  • the United Arab Emirates, at an unidentified group.

Desk 1 describes the verticals, and organizational particulars, for victims in Israel.

Desk 1. Verticals and organizational particulars for victims in Israel




·       An automotive firm specializing in customized modifications.

·       An automotive restore and upkeep firm.


·       An Israeli media outlet.


·       A civil engineering agency.

·       An environmental engineering agency.

·       An architectural design agency.

Monetary providers

·       A monetary providers firm that makes a speciality of funding counseling.

·       An organization that manages royalties.


·       A medical care supplier.

Insurance coverage

·       An insurance coverage firm that operates an insurance coverage market.

·       A business insurance coverage firm.


·       A agency specializing in medical regulation.


·       A number of electronics manufacturing firms.

·       An organization that manufactures metal-based business merchandise.

·       A multinational expertise manufacturing firm.


·       A meals retailer.

·       A multinational diamond retailer.

·       A skincare merchandise retailer.

·       A window therapy retailer and installer.

·       A world digital components provider.

·       A bodily entry management provider.


·       An IT providers expertise firm.

·       An IT options supplier.


·       A telecommunications firm.


·       A number of unidentified organizations.


In August 2021, the Israeli sufferer above that operates an insurance coverage market was attacked by Ballistic Bobcat with the instruments CISA reported in November 2021. The symptoms of compromise we noticed are:

  • MicrosoftOutlookUpdateSchedule,
  • MicrosoftOutlookUpdateSchedule.xml,
  • GoogleChangeManagement, and
  • GoogleChangeManagement.xml.

Ballistic Bobcat instruments communicated with the identical command and management (C&C) server as within the CISA report: 162.55.137[.]20.

Then, in September 2021, the identical sufferer acquired the following era of Ballistic Bobcat instruments: the PowerLess backdoor and its supporting toolset. The symptoms of compromise we noticed have been:

  • http://162.55.137[.]20/gsdhdDdfgA5sS/ff/dll.dll,
  • windowsprocesses.exe, and
  • http://162.55.137[.]20/gsdhdDdfgA5sS/ff/windowsprocesses.exe.

On November 18th, 2021, the group then deployed one other software (Plink) that was coated within the CISA report, as MicrosoftOutLookUpdater.exe. Ten days later, on November 28th, 2021, Ballistic Bobcat deployed the Merlin agent (the agent portion of an open-source post-exploitation C&C server and agent written in Go). On disk, this Merlin agent was named googleUpdate.exe, utilizing the identical naming conference as described within the CISA report to cover in plain sight.

The Merlin agent executed a Meterpreter reverse shell that referred to as again to a brand new C&C server, 37.120.222[.]168:80. On December 12th, 2021, the reverse shell dropped a batch file, set up.bat, and inside minutes of executing the batch file, Ballistic Bobcat operators pushed their latest backdoor, Sponsor. This might change into the third model of the backdoor.

Technical evaluation

Preliminary entry

We have been capable of establish a possible technique of preliminary entry for 23 of the 34 victims that we noticed in ESET telemetry. Much like what was reported within the PowerLess and CISA reviews, Ballistic Bobcat most likely exploited a identified vulnerability, CVE-2021-26855, in Microsoft Alternate servers to realize a foothold on these techniques.

For 16 of the 34 victims, it seems Ballistic Bobcat was not the one risk actor with entry to their techniques. This may increasingly point out, together with the big variety of victims and the obvious lack of apparent intelligence worth of some victims, that Ballistic Bobcat engaged in scan-and-exploit habits, versus a focused marketing campaign in opposition to preselected victims.


Open-source instruments

Ballistic Bobcat employed various open-source instruments in the course of the Sponsoring Entry marketing campaign. These instruments and their capabilities are listed in Desk 2.

Desk 2. Open-source instruments utilized by Ballistic Bobcat




Maps a hostname to an IP handle inside the native community.


RevSocks, a reverse tunnel utility.


Mimikatz, with an unique filename of midongle.exe and full of the Armadillo PE packer.


GO Easy Tunnel (GOST), a tunneling utility written in Go.


Chisel, a TCP/UDP tunnel over HTTP utilizing SSH layers.


RevSocks tunnel, protected with the trial model of the Enigma Protector software program safety.


Plink (PuTTY Hyperlink), a command line connection software.


A password restoration software for passwords saved in net browsers.


A software for interacting with, and extracting knowledge from, SQL databases.


ProcDump, a  Sysinternals command line utility for monitoring functions and producing crash dumps.

Batch recordsdata

Ballistic Bobcat deployed batch recordsdata to victims’ techniques moments earlier than deploying the Sponsor backdoor. File paths we’re conscious of are:

  • C:inetpubwwwrootaspnet_clientInstall.bat
  • %USERPROFILEpercentDesktopInstall.bat
  • %WINDOWSpercentTasksInstall.bat

Sadly, we have been unable to acquire any of those batch recordsdata. Nevertheless, we consider they write innocuous configuration recordsdata to disk, which the Sponsor backdoor requires to perform totally. These configuration filenames have been taken from the Sponsor backdoors however have been by no means collected:

  • config.txt
  • node.txt
  • error.txt
  • Uninstall.bat

We consider that the batch recordsdata and configuration recordsdata are a part of the modular improvement course of that Ballistic Bobcat has favored over the previous few years.

Sponsor backdoor

Sponsor backdoors are written in C++ with compilation timestamps and Program Database (PDB) paths as proven in Desk 3. A word on model numbers: the column Model represents the model that we observe internally primarily based on the linear development of Sponsor backdoors the place adjustments are created from one model to the following. The Inside model column incorporates the model numbers noticed in every Sponsor backdoor and are included for ease of comparability when analyzing these and different potential Sponsor samples.

Desk 3. Sponsor compilation timestamps and PDBs


Inside model

Compilation timestamp




2021-08-29 09:12:51




2021-10-09 12:39:15




2021-11-24 11:51:55




2022-02-19 13:12:07



2022-06-19 14:14:13


The preliminary execution of Sponsor requires the runtime argument set up, with out which Sponsor gracefully exits, possible a easy anti-emulation/anti-sandbox approach. If handed that argument, Sponsor creates a service referred to as SystemNetwork (in v1) and Replace (in all the opposite variations). It units the service’s Startup Kind to Computerized, and units it to run its personal Sponsor course of, and grants it full entry. It then begins the service.

Sponsor, now working as a service, makes an attempt to open the aforementioned configuration recordsdata beforehand positioned on disk. It appears for config.txt and node.txt, each within the present working listing. If the primary is lacking, Sponsor units the service to Stopped and gracefully exits.

Backdoor configuration

Sponsor’s configuration, saved in config.txt, incorporates two fields:

  • An replace interval, in seconds, to periodically contact the C&C server for instructions.
  • An inventory of C&C servers, known as relays in Sponsor’s binaries.

The C&C servers are saved encrypted (RC4), and the decryption key’s current within the first line of config.txt. Every of the fields, together with the decryption key, have the format proven in Determine 3.

Figure 3. Format of configuration fields in config.txt
Determine 3. Format of configuration fields in config.txt

These subfields are:

  • config_start: signifies the size of config_name, if current, or zero, if not. Utilized by the backdoor to know the place config_data begins.
  • config_len: size of config_data.
  • config_name: non-compulsory, incorporates a reputation given to the configuration subject.
  • config_data: the configuration itself, encrypted (within the case of C&C servers) or not (all the opposite fields).

Determine 4 exhibits an instance with color-coded contents of a potential config.txt file. Notice that this isn’t an precise file we noticed, however a fabricated instance.

Figure 4. Example of possible contents of config.txt
Determine 4. Instance of potential contents of config.txt

The final two fields in config.txt are encrypted with RC4, utilizing the string illustration of the SHA-256 hash of the desired decryption key, as the important thing to encrypt the information. We see that the encrypted bytes are saved hex-encoded as ASCII textual content.

Host info gathering

Sponsor gathers details about the host on which it’s working, reviews the entire gathered info to the C&C server, and receives a node ID, which is written to node.txt. Desk 4 lists keys and values within the Home windows registry that Sponsor makes use of to get the knowledge, and gives an instance of the information collected.

Desk 4. Data gathered by Sponsor

Registry key








Israel Commonplace Time

HKEY_USERS.DEFAULTControl PanelInternational








Intel(R) Core(TM) i7-8565U CPU @ 1.80GHz



Home windows 10 Enterprise N







Sponsor additionally collects the host’s Home windows area through the use of the next WMIC command:

wmic computersystem get area

Lastly, Sponsor makes use of Home windows APIs to gather the present username (GetUserNameW), decide if the present Sponsor course of is working as a 32- or 64-bit utility (GetCurrentProcess, then IsWow64Process(CurrentProcess)), and determines whether or not the system is working on battery energy or linked to an AC or DC energy supply (GetSystemPowerStatus).

One oddity concerning the 32- or 64-bit utility verify is that each one noticed samples of Sponsor have been 32-bit. This might imply that a few of the subsequent stage instruments require this info.

The collected info is distributed in a base64-encoded message that, earlier than encoding, begins with r and has the format proven in Determine 5.

Figure 5. Format of the message sent by Sponsor to register the victimized computer
Determine 5. Format of the message despatched by Sponsor to register the victimized pc

The knowledge is encrypted with RC4, and the encryption key’s a random quantity generated on the spot. The bottom line is hashed with the MD5 algorithm, not SHA-256 as beforehand talked about. That is the case for all communications the place Sponsor has to ship encrypted knowledge.

The C&C server replies with a quantity used to establish the victimized pc in later communications, which is written to node.txt. Notice that the C&C server is randomly chosen from the listing when the r message is distributed, and the identical server is utilized in all subsequent communications.

Command processing loop

Sponsor requests instructions in a loop, sleeping based on the interval outlined in config.txt. The steps are:

  1. Ship a chk=Take a look at message repeatedly, till the C&C server replies Okay.
  2. Ship a c (IS_CMD_AVAIL) message to the C&C server, and obtain an operator command.
  3. Course of the command.
    • If there’s output to be despatched to the C&C server, ship an a (ACK) message, together with the output (encrypted), or
    • If execution failed, ship an f (FAILED) message. The error message just isn’t despatched.
  4. Sleep.

The c message is distributed to request a command to execute, and has the format (earlier than base64 encoding) proven in Determine 6.

Figure 6. Format of the message sent by Sponsor to ask for commands to execute
Determine 6. Format of the message despatched by Sponsor to ask for instructions to execute

The encrypted_none subject within the determine is the results of encrypting the hardcoded string None with RC4. The important thing for encryption is the MD5 hash of node_id.

The URL used to contact the C&C server is constructed as: http://<IP_or_domain>:80. This may increasingly point out that 37.120.222[.]168:80 is the one C&C server used all through the Sponsoring Entry marketing campaign, because it was the one IP handle we noticed sufferer machines reaching out to on port 80.

Operator instructions

Operator instructions are delineated in Desk 5 and seem within the order wherein they’re discovered within the code. Communication with the C&C server happens over port 80.

Desk 5. Operator instructions and descriptions




Sends the method ID for the working Sponsor course of.


Executes a command, as laid out in a subsequent extra argument, on the Sponsor host utilizing the next string:

c:windowssystem32cmd.exe /c  <cmd>  > consequence.txt 2>&1

Outcomes are saved in consequence.txt within the present working listing. Sends an a message with the encrypted output to the C&C server if efficiently executed. If failed, sends an f message (with out specifying the error).


Receives a file from the C&C server and executes it. This command has many arguments: the goal filename to jot down the file into, the MD5 hash of the file, a listing to jot down the file to (or the present working listing, by default), a Boolean to point whether or not to run the file or not, and the contents of the executable file, base64-encoded. If no errors happen, an a message is distributed to the C&C server with Add and execute file efficiently or Add file efficiently with out execute (encrypted). If errors happen throughout execution of the file, an f message is distributed. If the MD5 hash of the contents of the file doesn’t match the offered hash, an e (CRC_ERROR) message is distributed to the C&C server (together with solely the encryption key used, and no different info). The usage of the time period Add right here is doubtlessly complicated because the Ballistic Bobcat operators and coders take the perspective from the server facet, whereas many would possibly view this as a obtain primarily based on the pulling of the file (i.e., downloading it) by the system utilizing the Sponsor backdoor.


Makes an attempt to obtain a file utilizing the URLDownloadFileW Home windows API and execute it. Success sends an a message with the encryption key used, and no different info. Failure sends an f message with the same construction.


Executes a file already on disk, Uninstall.bat within the present working listing, that more than likely incorporates instructions to delete recordsdata associated to the backdoor.


This command could be explicitly provided by an operator or could be inferred by Sponsor because the command to execute within the absence of some other command. Referred to inside Sponsor as NO_CMD, it executes a randomized sleep earlier than checking again in with the C&C server.


Updates the listing of C&Cs saved in config.txt within the present working listing. The brand new C&C addresses change the earlier ones; they don’t seem to be added to the listing. It sends an a message with
New relays changed efficiently (encrypted) to the C&C server if efficiently up to date.


Updates the predetermined check-in interval laid out in config.txt. It sends an a message with New interval changed efficiently to the C&C server if efficiently up to date.

Updates to Sponsor

Ballistic Bobcat coders made code revisions between Sponsor v1 and v2. The 2 most important adjustments within the latter are:

  • Optimization of code the place a number of longer capabilities have been minimized into capabilities and subfunctions, and
  • Disguising Sponsor as an updater program by together with the next message within the service configuration:

App updates are nice for each app customers and apps – updates imply that builders are all the time engaged on bettering the app, protecting in thoughts a greater buyer expertise with every replace.

Community infrastructure

Along with piggybacking on the C&C infrastructure used within the PowerLess marketing campaign, Ballistic Bobcat additionally launched a brand new C&C server. The group additionally utilized a number of IPs to retailer and ship assist instruments in the course of the Sponsoring Entry marketing campaign. We’ve confirmed that none of those IPs are in operation presently.


Ballistic Bobcat continues to function on a scan-and-exploit mannequin, in search of targets of alternative with unpatched vulnerabilities in internet-exposed Microsoft Alternate servers. The group continues to make use of a various open-source toolset supplemented with a number of customized functions, together with its Sponsor backdoor. Defenders can be nicely suggested to patch any internet-exposed gadgets and stay vigilant for brand spanking new functions popping up inside their organizations.

For any inquiries about our analysis printed on WeLiveSecurity, please contact us at threatintel@eset.com.
ESET Analysis provides non-public APT intelligence reviews and knowledge feeds. For any inquiries about this service, go to the ESET Risk Intelligence web page.










Ballistic Bobcat backdoor, Sponsor (v1).




Ballistic Bobcat backdoor, Sponsor (v2).




Ballistic Bobcat backdoor, Sponsor (v3).




Ballistic Bobcat backdoor, Sponsor (v4).




Ballistic Bobcat backdoor, Sponsor (v5, aka Alumina).




RevSocks reverse tunnel.




ProcDump, a command line utility for monitoring functions and producing crash dumps.








GO Easy Tunnel (GOST).




Chisel reverse tunnel.




Host2IP discovery software.




RevSocks tunnel, protected with the trial model of the Enigma Protector software program safety.




Plink (PuTTY Hyperlink), a command line connection software.




A password restoration software for passwords saved in net browsers.




A software for interacting with, and extracting knowledge from, SQL databases.


File paths

The next is a listing of paths the place the Sponsor backdoor was deployed on victimized machines.







%WINDIRpercentINFMSExchange Supply DSN






First seen

Final seen



Hetzner On-line GMBH



PowerLess C&C.


M247 LTD



Sponsor C&C.





Help instruments obtain website.


The Infrastructure Group B.V.



Help instruments obtain website.

This desk was constructed utilizing model 13 of the MITRE ATT&CK framework.







Lively Scanning: Vulnerability Scanning

Ballistic Bobcat scans for weak variations of Microsoft Alternate Servers to take advantage of.

Useful resource Growth


Develop Capabilities: Malware

Ballistic Bobcat designed and coded the Sponsor backdoor.


Get hold of Capabilities: Instrument

Ballistic Bobcat makes use of numerous open-source instruments as a part of the Sponsoring Entry marketing campaign.

Preliminary Entry


Exploit Public-Going through Utility

Ballistic Bobcat targets internet-exposed  Microsoft Alternate Servers.



Command and Scripting Interpreter: Home windows Command Shell

The Sponsor backdoor makes use of the Home windows command shell to execute instructions on the sufferer’s system.


System Companies: Service Execution

The Sponsor backdoor units itself as a service and initiates its major capabilities after the service is executed.



Create or Modify System Course of: Home windows Service

Sponsor maintains persistence by making a service with computerized startup that executes its major capabilities in a loop.

Privilege Escalation


Legitimate Accounts: Native Accounts

Ballistic Bobcat operators try to steal credentials of legitimate customers after initially exploiting a system earlier than deploying the Sponsor backdoor.

Protection Evasion


Deobfuscate/Decode Information or Data

Sponsor shops info on disk that’s encrypted and obfuscated, and deobfuscates it at runtime.


Obfuscated Information or Data

Configuration recordsdata that the Sponsor backdoor requires on disk are encrypted and obfuscated.


Legitimate Accounts: Native Accounts

Sponsor is executed with admin privileges, possible utilizing credentials that operators discovered on disk; together with Ballistic Bobcat’s innocuous naming conventions, this enables Sponsor to mix into the background.

Credential Entry


Credentials from Password Shops: Credentials from Internet Browsers

Ballistic Bobcat operators use open-source instruments to steal credentials from password shops inside net browsers.



Distant System Discovery

Ballistic Bobcat makes use of the Host2IP software, beforehand utilized by Agrius, to find different techniques inside reachable networks and correlate their hostnames and IP addresses.

Command and Management


Knowledge Obfuscation

The Sponsor backdoor obfuscates knowledge earlier than sending it to the C&C server.

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