Advisory on Malware Campaigns Spreading Through WhatsApp
Published Sources: SingCERT
What is affected, what to do
SingCERT has received multiple reports of malware campaigns involving malicious files being distributed through compromised WhatsApp accounts. Stay vigilant and avoid opening unexpected attachments, even from known contacts.
The available sources name no fixed version. Check the vendor guidance in the references below.
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Priority
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CVSS v3
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- Severity
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Priority (0–325)
The priority score is a consolidated metric that condenses several individual signals into a single, action-guiding ranking: technical severity (CVSS), exploitation likelihood (EPSS), known-exploited status (KEV) and the context of the affected asset. The aim is to answer the only truly important question in vulnerability management: what first?
Read in glossary- 30.00 Methodology
Exploit maturity
An exploit is code or a technique that specifically uses a concrete vulnerability to force unintended behaviour — such as executing code or escalating privileges. It is the tool that turns a theoretical flaw into a practical attack.
Read in glossary- no public PoC known
KEV status
The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching.
Read in glossary- —
- Published
Classification under NIS2 and CRA
Rule-based classification from exploitation status and severity. It does not replace a case-by-case assessment.
NIS2
NIS2 is EU Directive (EU) 2022/2555 to raise the level of cybersecurity across the Union. It substantially broadens obligations compared with the first NIS directive: more sectors, mandatory risk management, staged reporting duties and personal accountability of senior management.
Read in glossary- Handle the vulnerability in regular vulnerability handling under Art. 21(2)(e) NIS2.
CRA
The CRA is EU Regulation (EU) 2024/2847 setting horizontal cybersecurity requirements for „products with digital elements“ — from industrial controllers and software to connected consumer devices. For the first time manufacturers must ensure security across the entire product lifecycle, handle vulnerabilities and provide security updates.
Read in glossary- From 11.12.2027, Annex I Part II CRA requires manufacturers of affected products with digital elements to handle vulnerabilities without delay and provide security updates.
ISO/IEC 27001
ISO/IEC 27001 is the internationally leading standard for an information security management system (ISMS). It describes a risk-based, process-oriented framework to systematically plan, implement, review and improve information security.
Read in glossary- Control A.8.8, management of technical vulnerabilities: assess relevance to your systems, plan remediation and keep evidence.
Description
SingCERT has received multiple reports of malware campaigns involving malicious files being distributed through compromised WhatsApp accounts. Stay vigilant and avoid opening unexpected attachments, even from known contacts. Background SingCERT has received multiple reports of malware campaigns involving malicious files being distributed through compromised WhatsApp accounts (as shown in Figure 1 ). These files may be disguised as legitimate business documents or other seemingly harmless attachments, exploiting the trust recipients place in messages received from known contacts. In reported cases, users who downloaded and opened malicious files received through WhatsApp subsequently discovered that similar files had been sent to their contacts without their knowledge or authorisation. This could allow the malware to spread further and compromise other WhatsApp accounts. Figure 1: Sample WhatsApp Message and Malicious File Impact Users who run malicious files received through WhatsApp risk compromising their devices and exposing sensitive information. Depending on the type of malware involved, threat actors could: Gain unauthorised access to affected devices; Steal sensitive information, including account credentials; Hijack active WhatsApp Web sessions to distribute malicious files to the affected users' contacts; and Monitor activities on affected devices, including online banking activities. Recommendations Users and organisations are advised to adopt the following precautionary measures: Exercise caution with unexpected attachments - Avoid downloading or opening unexpected files received through WhatsApp, even if they come from someone you know. Be cautious with files ending in .exe, .iso or .zip, as they may contain malware. Verify with the sender - If you receive an unexpected file, contact the sender through an alternative trusted communication channel, such as a phone call, to check if they really sent it. Respond promptly if you have opened the file - Disconnect the affected device from the network and scan it using antivirus software. Inform your contacts that your account may have been compromised and warn them not to open files sent from your account. MyCERT has observed host indicators which should be checked for as well: a C:\kouren or C:\cool directory on the system drive; an msiexec process installing UEMSAgent.msi with SERVER_ROOT_CRT= and DS_ROOT_CRT= parameters; certificates with CN=ManageEngineCA appearing in the trusted root store; outbound TCP connections to port 8383 at the backend addresses in Section 4.0; a ManageEngine UEMS_Agent installation on a host that has never legitimately run endpoint-management tooling. Secure WhatsApp accounts - Review linked devices in WhatsApp settings and log out of unfamiliar or unauthorised sessions. Enable two-step verification and follow WhatsApp's official account recovery procedures if your account has been compromised. Avoid accessing WhatsApp Web or other sensitive accounts from a potentially infected device until it has been secured. Keep devices protected - Ensure operating systems and applications are updated with the latest security patches, and use reputable antivirus or endpoint protection software. More information can be found here . Report unauthorised transactions - If you notice any unauthorised banking transactions, report them to your bank and the Police immediately. References https://www.thestar.com.my/tech/tech-news/2026/09/29/malaysians-report-being-targeted-by-malware-file-sent-through-whatsapp https://www.csa.gov.sg/resources/tips-and-resources/recommended-security-apps-list/ https://www.mycert.org.my/portal/advisory?id=MA-1491.102026
Source: CSA/SingCERT