Caçando Lazarus: Dentro da Infraestrutura de C2 da Entrevista Contagiosa

Ruslan Mikhalov Chief of Threat Research at SOC Prime

Seguir

Caçando Lazarus: Dentro da Infraestrutura de C2 da Entrevista Contagiosa

Detection stack

AIDR
Alert
ETL
Query

Relatório de Ameaça
Fluxo de Ataque
Detecções
Simulações

Resumo

Red Asgard relatou um comprometimento da cadeia de suprimentos ligado a um projeto de criptomoeda promovido via Upwork, onde operadores do Lazarus incorporaram código malicioso no processo de construção/workflow. A cadeia abusa da execução automática de tarefas do VSCode, de um backdoor Node.js implementado através do construtor Function, e da entrega de carga útil protegida por cookies para buscar JavaScript malicioso da infraestrutura de comando-e-controle hospedada no Vercel. O stack C2 é dividido em domínios Vercel de primeiro estágio e servidores Windows dedicados de segundo estágio, os quais entregam um backdoor Python pesadamente ofuscado com funcionalidade de mineração XMRig. A campanha também utiliza dead drops no Pastebin, um protocolo binário personalizado e compartimentação estrita de credenciais para complicar a análise e o desmantelamento.

Investigação

Os pesquisadores enumeraram três domínios Vercel expondo endpoints autenticados por token e identificaram cinco sistemas C2 dedicados executando Express.js on porta 1244. Eles também documentaram uma técnica de timing-oracle usada para inferir ou enumerar tokens de campanhas ativas. A engenharia reversa de uma carga útil com 64 camadas revelou, em última análise, um componente trojanizado que persiste através do posicionamento na pasta de Inicialização e criação de tarefas agendadas. Descobertas adicionais incluíram credenciais MongoDB hard-coded, aproximadamente 1.000 URLs de dead drops no Pastebin, e ouvintes de protocolo Z238 personalizado em várias portas.

Mitigação

Bloquear comunicações de saída para os domínios Vercel identificados e restringir egressos para as portas 1244, 1249, e 22411–22412. Monitorar a criação de Windows Update Script.pyw em locais de Inicialização, tarefas agendadas chamadas “Runtime Broker” e execução suspeita de msedge.exe consistente com disfarce de minerador. Detectar processos Node.js invocando Function.constructor e atividade HTTP POST anômala para endpoints /keys. Reduzir a exposição desabilitando tarefas automáticas do VSCode e revisando scripts de pacote antes de executar npm install ou passos de construção em repositórios não confiáveis.

Resposta

Se indicadores forem observados, isolar o sistema afetado, terminar processos suspeitos e preservar artefatos de memória e disco para revisão forense. Revogar quaisquer credenciais MongoDB expostas e rotacionar todos os segredos de contas de serviço relevantes. Executar um inventário de contas e acessos para identificar usuários impactados, depois redefinir credenciais e invalidar sessões/tokens ativos. Notificar partes interessadas internas e coordenar com as autoridades se houver evidência de roubo de criptomoedas ou comprometimento de carteiras.

“graph TB %% Class definitions classDef technique fill:#cce5ff classDef artifact fill:#e2f7d6 %% Step 1 u2013 Phishing via Service tech_phishing[“Técnica – T1566.003 Phishing: Spearphishing via Service Descrição: O atacante se passou por um freelancer no Upwork e postou uma entrevista de emprego falsa para entregar um repositório de código malicioso.”] class tech_phishing technique artifact_upwork[“Artefato – Nome: Anúncio de Emprego Falso no Upwork Propósito: Atrair a vítima para baixar um repositório malicioso.”] class artifact_upwork artifact tech_phishing u002du002d>|entrega| artifact_upwork %% Step 2 u2013 Comprometimento da Cadeia de Suprimentos tech_supplychain[“Técnica – T1195.001 Comprometimento da Cadeia de Suprimentos: Comprometer Dependências de Software e Ferramentas de Desenvolvimento Descrição: VSCode <code>tasks.json</code> malicioso e código JavaScript injetado no repositório.”] class tech_supplychain technique artifact_tasksjson[“Artefato – Nome: VSCode <code>tasks.json</code> Conteúdo: Definição de Tarefa maliciosa invocando o construtor de função JavaScript e <code>getCookie()</code>.”] class artifact_tasksjson artifact artifact_upwork u002du002d>|contém| artifact_tasksjson artifact_tasksjson u002du002d>|permite| tech_supplychain %% Step 3 u2013 Execução pelo Usuário tech_userexec[“Técnica – T1204.002 Execução pelo Usuário: Arquivo Malicioso Descrição: A vítima abriu a pasta do projeto no VSCode, acionando a autoexecução das tarefas maliciosas.”] class tech_userexec technique artifact_tasksjson u002du002d>|acionado por| tech_userexec %% Step 4 u2013 Execução de JavaScript tech_jsexec[“Técnica – T1059.007 Interpretador de Comando e Script: JavaScript Descrição: JavaScript executado via tarefas do VSCode e construtor de funções para baixar cargas adicionais.”] class tech_jsexec technique tech_userexec u002du002d>|leva a| tech_jsexec %% Step 5 u2013 Backdoor em Python tech_python[“Técnica – T1059.006 Interpretador de Comando e Script: Python Descrição: Backdoor em Python fortemente ofuscado (<code>bro_*.js</code>) baixado e executado no host da vítima.”] class tech_python technique artifact_python_backdoor[“Artefato – Nome: Backdoor em Python Ofuscado (<code>bro_*.js</code>) Características: Codificação e decodificação em múltiplas camadas.”] class artifact_python_backdoor artifact tech_jsexec u002du002d>|baixa| artifact_python_backdoor artifact_python_backdoor u002du002d>|executa| tech_python %% Step 6 u2013 Persistência no Início tech_startup[“Técnica – T1037.005 Scripts de Inicialização: Itens de Inicialização Descrição: Persistência ao colocar <code>Windows Update Script.pyw</code> na pasta de Inicialização.”] class tech_startup technique artifact_startup_script[“Artefato – Nome: <code>Windows Update Script.pyw</code> Localização: Pasta de Inicialização”] class artifact_startup_script artifact tech_python u002du002d>|cria| artifact_startup_script artifact_startup_script u002du002d>|permite| tech_startup %% Step 7 u2013 Tarefa Agendada tech_schedtask[“Técnica – T1053 Tarefa/Job Agendado Descrição: Tarefa agendada chamada u201cRuntime Brokeru201d criada para executar no logon.”] class tech_schedtask technique artifact_schedtask[“Artefato – Nome: Tarefa Agendada u201cRuntime Brokeru201d Acionador: No logon do usuário”] class artifact_schedtask artifact tech_startup u002du002d>|adiciona| artifact_schedtask artifact_schedtask u002du002d>|executa| tech_schedtask %% Step 8 u2013 Colheita de Credenciais de Navegadores tech_credbrowser[“Técnica – T1555.003 Credenciais de Armazenamento de Senhas: Credenciais de Navegadores Web Descrição: Malware coletou dados de perfis de navegadores e credenciais armazenadas.”] class tech_credbrowser technique artifact_browser_data[“Artefato – Dados: Senhas e cookies extraídos do navegador”] class artifact_browser_data artifact tech_schedtask u002du002d>|coleta| tech_credbrowser tech_credbrowser u002du002d>|armazena| artifact_browser_data %% Step 9 u2013 Roubo de Cookie de Sessão Web tech_stealcookie[“Técnica – T1539 Roubo de Cookie de Sessão Web Descrição: A função <code>getCookie()</code> recuperou cookies de sessão do navegador da vítima.”] class tech_stealcookie technique artifact_getcookie[“Artefato – Dados: Cookies de sessão capturados de navegadores”] class artifact_getcookie artifact tech_credbrowser u002du002d>|permite| tech_stealcookie tech_stealcookie u002du002d>|produz| artifact_getcookie %% Step 10 u2013 Uso de Material de Autenticação Alternativo tech_altauth[“Técnica – T1550.004 Uso de Material de Autenticação Alternativo: Cookie de Sessão Web Descrição: Cookies colhidos usados posteriormente para sequestrar sessões web autenticadas.”] class tech_altauth technique artifact_getcookie u002du002d>|utilizado por| tech_altauth %% Step 11 u2013 Mascaramento tech_masquerade[“Técnica – T1036.003 Mascaramento: Renomear Utilitários Legítimos Descrição: Binários maliciosos renomeados para u201cRuntime Broker.exeu201d e u201cmsedge.exeu201d.”] class tech_masquerade technique artifact_renamed_bins[“Artefato – Arquivos: <code>Runtime Broker.exe</code>, <code>msedge.exe</code> (malicioso)”] class artifact_renamed_bins artifact tech_altauth u002du002d>|entrega| artifact_renamed_bins artifact_renamed_bins u002du002d>|usado em| tech_masquerade %% Step 12 u2013 Comprometimento de Defesas tech_impairdefense[“Técnica – T1562 Comprometimento de Defesas Descrição: Exclusões do Windows Defender adicionadas via PowerShell para evadir detecção.”] class tech_impairdefense technique artifact_defender_exclusion[“Artefato – Comando: Script PowerShell adicionando caminhos de exclusão do Defender”] class artifact_defender_exclusion artifact tech_masquerade u002du002d>|executa| artifact_defender_exclusion artifact_defender_exclusion u002du002d>|permite| tech_impairdefense %% Step 13 u2013 Arquivos Ofuscados tech_obfuscation[“Técnica – T1027 Arquivos ou Informações Ofuscadas Descrição: Payload utilizou 64 camadas de ofuscação aninhadas (Base85, XOR, zlib, Base64 invertido).”] class tech_obfuscation technique tech_impairdefense u002du002d>|protege| tech_obfuscation %% Step 14 u2013 Ocultar Artefatos tech_hideartifacts[“Técnica – T1564.012 Ocultar Artefatos: Exclusões de Arquivo/Caminho Descrição: Exclusões do Defender e arquivos ocultos usados para ocultar artefatos maliciosos.”] class tech_hideartifacts technique tech_obfuscation u002du002d>|facilita| tech_hideartifacts %% Step 15 u2013 Resolver Drop Morto tech_dead_drop[“Técnica – T1102.001 Serviço Web: Resolver Drop Morto Descrição: O malware buscou comandos em uma rede de ~1.000 contas de drop morto no Pastebin.”] class tech_dead_drop technique artifact_pastebin[“Artefato – Serviço: Contas no Pastebin de resolver drop morto”] class artifact_pastebin artifact tech_hideartifacts u002du002d>|recupera| artifact_pastebin artifact_pastebin u002du002d>|fornece comandos para| tech_dead_drop %% Step 16 u2013 Exfiltração via FTP tech_exfilftp[“Técnica – T1048.003 Exfiltração via Protocolo Alternativo: Protocolo Não C2 Não Criptografado Descrição: Dados coletados exfiltrados via FTP na porta 21.”] class tech_exfilftp technique artifact_ftp[“Artefato – Protocolo: FTP (porta 21) usado para transferência de dados”] class artifact_ftp artifact tech_dead_drop u002du002d>|envia dados via| tech_exfilftp tech_exfilftp u002du002d>|usa| artifact_ftp %% Step 17 u2013 Seqüestro de Recursos (Mineração de Monero) tech_resourcehijack[“Técnica – T1496.001 Seqüestro de Recursos: Seqüestro de Computação Descrição: Minerador de Monero XMRig implantado, disfarçado como u201cmsedge.exeu201d, para monetizar hosts infectados.”] class tech_resourcehijack technique artifact_xmrig[“Artefato – Arquivo: Binário do minerador XMRig nomeado <code>msedge.exe</code>”] class artifact_xmrig artifact tech_exfilftp u002du002d>|fornece recursos para| tech_resourcehijack tech_resourcehijack u002du002d>|executa| artifact_xmrig %% Step 18 u2013 Descoberta de Informações do Navegador tech_browserdisc[“Técnica – T1217 Descoberta de Informações do Navegador Descrição: O atacante enumerou informações do navegador para localizar credenciais adicionais e dados de sessão.”] class tech_browserdisc technique artifact_browser_info[“Artefato – Dados: Versão do navegador, caminhos de perfil, extensões instaladas”] class artifact_browser_info artifact tech_resourcehijack u002du002d>|coleta| tech_browserdisc tech_browserdisc u002du002d>|reúne| artifact_browser_info “

Fluxo de Ataque

Visualizar

Execução da Simulação

Pré-requisito: O Check de Pré-voo de Telemetria e Linha Base deve ter passado.

Narrativa e Comandos do Ataque

O adversário copia o legítimo RuntimeBroker.exe binário para um local não padrão (%TEMP%) para mascarar-se como um processo confiável enquanto evita a detecção baseada em caminhos de sistema conhecidos. Ao executar a cópia, o evento de criação do processo contém o nome de imagem esperado, mas um caminho que falha na verificação de contenção “System32”, satisfazendo selection_runtime.

Script de Teste de Regressão

# -----------------------------------------------
# TC-20260114-A1B2C – Simulação de Mascaramento
# -----------------------------------------------

# 1. Definir caminhos
$src  = "$env:SystemRootSystem32RuntimeBroker.exe"
$dest = "$env:TEMPRuntimeBroker.exe"

# 2. Copiar o binário legítimo para um diretório não-sistema
Copy-Item -Path $src -Destination $dest -Force

# 3. Executar o binário copiado (isso deve acionar a regra Sigma)
Start-Process -FilePath $dest -WindowStyle Hidden

# 4. OPCIONAL: Simular o cenário de mascaramento de msedge (miner)
#    (Copiar qualquer executável benigno, renomear para msedge.exe, colocar em %LOCALAPPDATA%MicrosoftWindowsApplications)
$minerSrc  = "$env:SystemRootSystem32notepad.exe"
$minerDest = "$env:LOCALAPPDATAMicrosoftWindowsApplicationsmsedge.exe"
Copy-Item -Path $minerSrc -Destination $minerDest -Force
Start-Process -FilePath $minerDest -WindowStyle Hidden
# -----------------------------------------------

Comandos de Limpeza

# Remover as cópias maliciosas
Remove-Item -Path "$env:TEMPRuntimeBroker.exe" -Force -ErrorAction SilentlyContinue
Remove-Item -Path "$env:LOCALAPPDATAMicrosoftWindowsApplicationsmsedge.exe" -Force -ErrorAction SilentlyContinue

Junte-se à plataforma Detection as Code da SOC Prime para melhorar a visibilidade das ameaças mais relevantes para o seu negócio. Para ajudá-lo a começar e gerar valor imediato, agende uma reunião agora com os especialistas da SOC Prime.

Cadastre-se Gratuitamente

Name	Descripiton
PHPSESSID	Preserves user session state across page requests. Cookie generated by applications based on the PHP language. This is a general purpose identifier used to maintain user session variables. It is normally a random generated number, how it is used can be specific to the site, but a good example is maintaining a logged-in status for a user between pages.
sp_i	Used to store information about authenticated User.
sp_r	Used to store information about authenticated User.
sp_a	Used to store information about authenticated User.

Name	Descripiton
tuuid	Collects anonymous data related to the user's visits to the website, such as the number of visits, average time spent on the website and what pages have been loaded.
tuuid_last_update	Collects anonymous data related to the user's visits to the website, such as the number of visits, average time spent on the website and what pages have been loaded.
um	Collects anonymous data related to the user's visits to the website, such as the number of visits, average time spent on the website and what pages have been loaded.
umeh	Collects anonymous data related to the user's visits to the website, such as the number of visits, average time spent on the website and what pages have been loaded.
na_sc_x	Used by the social sharing platform AddThis to keep a record of parts of the site that has been visited in order to recommend other parts of the site.
APID	Collects anonymous data related to the user's visits to the website.
IDSYNC	Collects anonymous data related to the user's visits to the website.
_cc_aud	Collects anonymous statistical data related to the user's website visits, such as the number of visits, average time spent on the website and what pages have been loaded. The purpose is to segment the website's users according to factors such as demographics and geographical location, in order to enable media and marketing agencies to structure and understand their target groups to enable customised online advertising.
_cc_cc	Collects anonymous statistical data related to the user's website visits, such as the number of visits, average time spent on the website and what pages have been loaded. The purpose is to segment the website's users according to factors such as demographics and geographical location, in order to enable media and marketing agencies to structure and understand their target groups to enable customised online advertising.
_cc_dc	Collects anonymous statistical data related to the user's website visits, such as the number of visits, average time spent on the website and what pages have been loaded. The purpose is to segment the website's users according to factors such as demographics and geographical location, in order to enable media and marketing agencies to structure and understand their target groups to enable customised online advertising.
_cc_id	Collects anonymous statistical data related to the user's website visits, such as the number of visits, average time spent on the website and what pages have been loaded. The purpose is to segment the website's users according to factors such as demographics and geographical location, in order to enable media and marketing agencies to structure and understand their target groups to enable customised online advertising.
dpm	Via a unique ID that is used for semantic content analysis, the user's navigation on the website is registered and linked to offline data from surveys and similar registrations to display targeted ads.
acs	Collects anonymous data related to the user's visits to the website, such as the number of visits, average time spent on the website and what pages have been loaded, with the purpose of displaying targeted ads.
clid	Collects anonymous data related to the user's visits to the website, such as the number of visits, average time spent on the website and what pages have been loaded, with the purpose of displaying targeted ads.
KRTBCOOKIE_#	Registers a unique ID that identifies the user's device during return visits across websites that use the same ad network. The ID is used to allow targeted ads.
PUBMDCID	Registers a unique ID that identifies the user's device during return visits across websites that use the same ad network. The ID is used to allow targeted ads.
PugT	Registers a unique ID that identifies the user's device during return visits across websites that use the same ad network. The ID is used to allow targeted ads.
ssi	Registers a unique ID that identifies a returning user's device. The ID is used for targeted ads.
_tmid	Registers a unique ID that identifies the user's device upon return visits. The ID is used to target ads in video clips.
wam-sync	Used by the advertising platform Weborama to determine the visitor's interests based on pages visits, content clicked and other actions on the website.
wui	Used by the advertising platform Weborama to determine the visitor's interests based on pages visits, content clicked and other actions on the website.
AFFICHE_W	Used by the advertising platform Weborama to determine the visitor's interests based on pages visits, content clicked and other actions on the website.
B	Collects anonymous data related to the user's website visits, such as the number of visits, average time spent on the website and what pages have been loaded. The registered data is used to categorise the users' interest and demographical profiles with the purpose of customising the website content depending on the visitor.
1P_JAR	These cookies are used to gather website statistics, and track conversion rates.
APISID	Google set a number of cookies on any page that includes a Google reCAPTCHA. While we have no control over the cookies set by Google, they appear to include a mixture of pieces of information to measure the number and behaviour of Google reCAPTCHA users.
HSID	Google set a number of cookies on any page that includes a Google reCAPTCHA. While we have no control over the cookies set by Google, they appear to include a mixture of pieces of information to measure the number and behaviour of Google reCAPTCHA users.
NID	Google set a number of cookies on any page that includes a Google reCAPTCHA. While we have no control over the cookies set by Google, they appear to include a mixture of pieces of information to measure the number and behaviour of Google reCAPTCHA users.
SAPISID	Google set a number of cookies on any page that includes a Google reCAPTCHA. While we have no control over the cookies set by Google, they appear to include a mixture of pieces of information to measure the number and behaviour of Google reCAPTCHA users.
SID	Google set a number of cookies on any page that includes a Google reCAPTCHA. While we have no control over the cookies set by Google, they appear to include a mixture of pieces of information to measure the number and behaviour of Google reCAPTCHA users.
SIDCC	Security cookie to protect users data from unauthorised access.
SSID	Google set a number of cookies on any page that includes a Google reCAPTCHA. While we have no control over the cookies set by Google, they appear to include a mixture of pieces of information to measure the number and behaviour of Google reCAPTCHA users.
__utmx	This cookie is associated with Google Website Optimizer, a tool designed to help site owners improve their wbesites. It is used to distinguish between two varaitions a webpage that might be shown to a visitor as part of an A/B split test. This helps site owners to detemine which version of a page performs better, and therefore helps to improve the website.
__utmxx	This cookie is associated with Google Website Optimizer, a tool designed to help site owners improve their wbesites. It is used to distinguish between two varaitions a webpage that might be shown to a visitor as part of an A/B split test. This helps site owners to detemine which version of a page performs better, and therefore helps to improve the website.

Name	Descripiton
_hjid	Hotjar cookie. This cookie is set when the customer first lands on a page with the Hotjar script. It is used to persist the random user ID, unique to that site on the browser. This ensures that behavior in subsequent visits to the same site will be attributed to the same user ID.
_hjIncludedInSample	This cookie is associated with web analytics functionality and services from Hot Jar, a Malta based company. It uniquely identifies a visitor during a single browser session and indicates they are included in an audience sample.
intercom-id-[xxx]	This cookie is used by Intercom as a session so that users can continue a chat as they move through the site.
intercom-session-[xxx]	Used to keeping track of sessions and remember logins and conversations.
demdex	Via a unique ID that is used for semantic content analysis, the user's navigation on the website is registered and linked to offline data from surveys and similar registrations to display targeted ads.
CookieConsent	Stores the user's cookie consent state for the current domain.
__cfduid	Used by the content network, Cloudflare, to identify trusted web traffic.
ss	These cookies enable the website to provide enhanced functionality and personalisation . They may be set by us or by third party providers whose services we have added to our pages. These services may include the Live Chat facility, Contact Us form(s), the Product Quotation forms and submission process, and the Email Newsletter sign up functionality .

Name	Descripiton
_ga	This cookie name is asssociated with Google Universal Analytics - which is a significant update to Google's more commonly used analytics service. This cookie is used to distinguish unique users by assigning a randomly generated number as a client identifier. It is included in each page. Registers a unique ID that is used to generate statistical data on how the visitor uses the website. request in a site and used to calculate visitor, session and campaign data for the sites analytics reports. By default it is set to expire after 2 years, although this is customisable by website owners.
_gat	Used by Google Analytics to throttle request rate. This cookie name is associated with Google Universal Analytics, according to documentation it is used to throttle the request rate - limiting the collection of data on high traffic sites. It expires after 10 minutes.
_gid	This cookie name is asssociated with Google Universal Analytics. This appears to be a new cookie and as of Spring 2017 no information is available from Google. It appears to store and update a unique value for each page visited. Registers a unique ID that is used to generate statistical data on how the visitor uses the website.
IDE	Used by Google DoubleClick to register and report the website user's actions after viewing or clicking one of the advertiser's ads with the purpose of measuring the efficacy of an ad and to present targeted ads to the user.
r/collect	Used by Google DoubleClick to register and report the website user's actions after viewing or clicking one of the advertiser's ads with the purpose of measuring the efficacy of an ad and to present targeted ads to the user.
test_cookie	Used to check if the user's browser supports cookies.
collect	Used to send data to Google Analytics about the visitor's device and behaviour. Tracks the visitor across devices and marketing channels.
ads/user-lists/#	These cookies may be set through our site by our advertising partners. They may be used by those companies to build a profile of your interests and show you relevant adverts on other sites.
c	Registers anonymised user data, such as IP address, geographical location, visited websites, and what ads the user has clicked, with the purpose of optimising ad display based on the user's movement on websites that use the same ad network.
khaos	Registers anonymised user data, such as IP address, geographical location, visited websites, and what ads the user has clicked, with the purpose of optimising ad display based on the user's movement on websites that use the same ad network.
put_#	Registers anonymised user data, such as IP address, geographical location, visited websites, and what ads the user has clicked, with the purpose of optimising ad display based on the user's movement on websites that use the same ad network.
rpb	Registers anonymised user data, such as IP address, geographical location, visited websites, and what ads the user has clicked, with the purpose of optimising ad display based on the user's movement on websites that use the same ad network.
rpx	Registers anonymised user data, such as IP address, geographical location, visited websites, and what ads the user has clicked, with the purpose of optimising ad display based on the user's movement on websites that use the same ad network.
tap.php	Registers anonymised user data, such as IP address, geographical location, visited websites, and what ads the user has clicked, with the purpose of optimising ad display based on the user's movement on websites that use the same ad network.