Detecção de PicassoLoader e njRAT: Hackers UAC-0057 Realizam Ataque Direcionado Contra Entidades Públicas Ucranianas

Veronika Zahorulko Detection Market Analyst

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Pesquisadores de cibersegurança emitem um alerta sobre um novo ataque cibernético direcionado pelo grupo UAC-0057 contra funcionários públicos ucranianos, utilizando arquivos XLS que contêm uma macro maliciosa espalhando PicassoLoader malware. O carregador malicioso é capaz de implantar outra cepa maliciosa chamada njRAT para espalhar a infecção ainda mais.

Distribuição de Malware PicassoLoader e njRAT por Hackers UAC-0057: Descrição do Ataque

Em 7 de julho de 2023, pesquisadores do CERT-UA descobriram alguns documentos XLS, um dos quais continha uma macro legítima, enquanto o outro incluía uma maliciosa que foi usada por hackers na fase inicial do ataque. O último visava decodificar, decifrar, manter persistência e executar o nefasto malware PicassoLoader nos sistemas-alvo. Os atacantes também usaram PicassoLoader para baixar, decifrar e executar utilitário de acesso remoto njRAT.

O último ataque pode ser vinculado ao grupo UAC-0057 também identificado como GhostWriter, que esteve por trás da campanha adversária de junho contra uma das universidades ucranianas espalhando PicassoLoader e Cobalt Strike Beacon. Na operação ofensiva em andamento abordada no respectivo alerta CERT-UA#6948, os atacantes UAC-0057 também visam as autoridades públicas ucranianas.

A investigação revelou que o malware PicassoLoader não será implantado por hackers se o sistema tiver proteção de segurança por produtos da Avast, FireEye e Fortinet.

Detectando Ataques UAC-0057 Aproveitando PicassoLoader e njRAT

Para equipar as equipes de segurança com algoritmos de detecção relevantes para identificar proativamente os últimos ciberataques UAC-0057 contra a Ucrânia, a Plataforma SOC Prime para defesa cibernética coletiva agrega um conjunto de regras Sigma. Os usuários podem obter este conjunto de detecção de ameaças pressionando o botão Explorar Detecções abaixo ou aplicando as tags personalizadas relevantes “CERT-UA#6948” e “UAC-0057” associadas ao alerta de segurança e aos identificadores do ator de ameaça.

Todas as regras estão mapeadas para o framework MITRE ATT&CK® v12, acompanhadas por inteligência de ameaça extensiva, e compatível com mais de 28 tecnologias SIEM, EDR e XDR para atender às necessidades específicas de cibersegurança das organizações.

botão Explorar Detecções

Para buscas simplificadas, as equipes podem procurar por IOCs vinculados ao coletivo UAC-0057 com a ajuda do Uncoder AI. Basta copiar e colar os IOCs listados pelo CERT-UA no último alerta no Uncoder AI e escolher o tipo de conteúdo alvo para construir sem esforço uma consulta IOC personalizada que corresponda ao seu stack tecnológico e às suas necessidades atuais de segurança.

Contexto MITRE ATT&CK

Para revisar um contexto mais amplo vinculado à operação UAC-0057 mais recente abordada no alerta CERT-UA#6948, todas as regras Sigma relacionadas estão alinhadas com ATT&CK v12 abordando os TTPs do adversário relevantes:

Tactics	Techniques	Sigma Rule
Initial Access	Phishing (T1566)	MSOffice Drops Files to Suspicious Location (via file_event)
		MSOffice Drops Suspicious Files (via file_event)
		Possible Word Macro Disguising Parent Process via WMI (via image_load)
Defense Evasion	System Binary Proxy Execution (T1218)	Execution of a Payload with a Spoofed Extension using Rundll32 or Regsvr32 (via cmdline)
Defense Evasion	System Binary Proxy Execution (T1218)	LOLBAS RunDLL32 (via cmdline)
Execution	Command and Scripting Interpreter (T1059)	Environment Variables in Command Line Arguments (via cmdline)
Execution	Windows Management Instrumentation (T1047)	Possible Word Macro Disguising Parent Process via WMI (via image_load)
Discovery	Software Discovery (T1518)	Possible AV Process Enumeration (via cmdline)
Discovery	Software Discovery (T1518)	Possible Antivirus or Firewall Software Enumeration (via process_creation)
Command and Control	Application Layer Protocol (T1071)	Suspicious Command and Control by Unusual Top Level Domain (TLD) DNS Request (via dns)

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.

Detecção de PicassoLoader e njRAT: Hackers UAC-0057 Realizam Ataque Direcionado Contra Entidades Públicas Ucranianas

Distribuição de Malware PicassoLoader e njRAT por Hackers UAC-0057: Descrição do Ataque

Detectando Ataques UAC-0057 Aproveitando PicassoLoader e njRAT

Contexto MITRE ATT&CK

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