Malware is no longer limited to traditional computer viruses that simply damage files or make a computer unstable. Modern malware is often designed specifically to steal information, obtain financial credentials, spy on users, establish persistent access, or move from one device to another.

Three particularly important questions for home users and businesses are:

1. Can malware steal passwords and banking information?
2. Can malware spread from one computer to another on the same network?
3. Can malware infect smartphones and tablets?

The answer to all three is yes, although the techniques, risks, and defenses vary considerably.

Understanding these capabilities is especially important because a computer may appear to work normally while malware silently steals information in the background.

1. Can Malware Steal Passwords and Banking Information?

Yes. Stealing usernames, passwords, financial credentials, authentication cookies, credit card information, cryptocurrency credentials, and other sensitive information is one of the major objectives of modern malware.

A category of malware commonly known as an information stealer or infostealer is specifically designed for this purpose.

Depending on its capabilities and the privileges it obtains, malware may attempt to collect information from web browsers, applications, files, system memory, clipboard contents, or user input.

What Information Can Malware Potentially Steal?

Credential-stealing malware may target information such as:

• Website usernames and passwords
• Email account credentials
• Online banking credentials
• Credit or debit card information
• Browser cookies
• Authentication tokens
• Autofill information
• Cryptocurrency wallet information
• FTP credentials
• VPN credentials
• Remote Desktop credentials
• Application login information
• Cloud-service credentials
• Social media credentials
• Business application credentials
• Personal documents
• Screenshots
• Clipboard contents
• Browser history
• System information

The exact information accessible depends on the operating system, application security controls, malware capabilities, permissions, and whether credentials are encrypted or otherwise protected.

2. How Does Malware Steal Passwords?

There is no single password-stealing technique. Different malware families use different methods.

Method 1: Keylogging

A keylogger records keyboard input.

For example, when a victim types:

• Email address
• Password
• Bank username
• Card information
• PIN or other credentials

malware may attempt to capture the keystrokes and transmit the information to an attacker.

Modern security protections can make this more difficult, but keylogging remains an important credential-theft technique.

Method 2: Stealing Stored Browser Credentials

Modern browsers can store usernames and passwords.

Information-stealing malware may attempt to access browser credential databases and associated encryption material.

Browsers commonly protect stored passwords using operating-system or application-level security mechanisms. Therefore, passwords are not necessarily stored as simple readable text.

However, malware executing under a compromised user context may sometimes be able to abuse legitimate APIs, steal relevant encryption material, or otherwise obtain access to information available to that user.

This is one reason why protecting the Windows or device account itself is extremely important.

Method 3: Stealing Browser Cookies and Sessions

Attackers do not always need your password.

After you successfully log in to a website, the browser may maintain an authenticated session using cookies or tokens.

Some malware attempts to steal these session artifacts.

If a service's security controls do not prevent reuse, stolen session information can potentially allow an attacker to impersonate an authenticated user.

This type of attack is particularly dangerous because, in some circumstances, possession of an already authenticated session can reduce the protection provided by a password or even multi-factor authentication.

Services can implement additional protections that make stolen sessions harder or impossible to reuse.

Method 4: Fake Login Windows

Some malware displays a fake authentication window that resembles:

• Microsoft 365
• Google
• Gmail
• Online banking
• Windows authentication
• VPN login
• Cryptocurrency services
• Business applications

The credentials entered into the fake window are sent to the attacker instead of—or in addition to—the legitimate service.

Method 5: Clipboard Monitoring

Malware may monitor the clipboard.

This can expose information that users copy and paste, including:

• Passwords
• Account numbers
• Cryptocurrency addresses
• Email addresses
• Authentication codes
• Sensitive business information

Some cryptocurrency-focused malware also attempts to replace a copied wallet address with an attacker's address.

Method 6: Screen Capture

Spyware and remote-access malware may capture screenshots.

This can expose information displayed on the screen even when the malware cannot directly retrieve it from the underlying application.

Method 7: Form and Browser Data Theft

Some sophisticated banking malware has historically targeted information entered into web forms or manipulated browser activity.

Potential targets include:

• Bank login credentials
• Payment information
• Personal identification details
• Card information
• Security answers

3. Can Malware Steal Banking Information?

Yes.

Malware specifically designed to target financial transactions is commonly called banking malware or a banking Trojan.

Depending on the malware and device, attacks may attempt to steal:

• Online banking usernames
• Banking passwords
• Card details
• Account information
• Transaction information
• Authentication information
• Browser sessions
• SMS-based authentication codes on compromised mobile devices

Some attacks also combine malware with phishing or social engineering.

For example, malware may steal basic account information while an attacker contacts the victim pretending to be from a bank and attempts to obtain additional authentication information.

4. Does Two-Factor Authentication Protect Against Malware?

Multi-factor authentication (MFA) provides significant additional protection, but it does not make a compromised device safe.

For example, malware may attempt to:

• Steal authenticated browser sessions
• Display fake authentication pages
• Capture information entered by the victim
• Abuse an already authenticated application
• Trick users into approving fraudulent login requests

Therefore, MFA should be used together with endpoint security, not as a replacement for it.

Where supported, phishing-resistant authentication methods such as passkeys or hardware security keys can provide stronger protection against many credential-phishing attacks.

5. Can Malware Spread From One Computer to Another on the Same Network?

Yes.

Certain types of malware can spread across a LAN or corporate network.

However, simply connecting two computers to the same network does not automatically mean malware can move between them.

Successful propagation usually requires some combination of:

• Vulnerable services
• Weak credentials
• Stolen administrator credentials
• Misconfigured network shares
• Exposed management services
• Unpatched operating systems
• Excessive permissions
• Poor network segmentation

6. How Malware Spreads Across Networks

Network Worms

A worm is malware capable of self-propagation.

Unlike many Trojans, which depend on users executing malicious software, a worm may scan a network for vulnerable systems and automatically attempt to compromise them.

A simplified process might be:

Infected Computer → Network Scan → Vulnerable Device Found → Exploit Attempt → New Device Compromised → Further Scanning

This behavior can allow an outbreak to grow rapidly.

Exploiting Vulnerable Network Services

Computers expose different services to communicate with other systems.

If a network-accessible service contains a serious vulnerability, malware may exploit it remotely.

Possible targets can include:

• File-sharing services
• Remote administration services
• Web servers
• Database servers
• Backup software
• Network appliances
• Remote desktop services
• Legacy protocols

Keeping operating systems and applications patched significantly reduces this risk.

Stolen Administrator Credentials

Malware does not always need a software vulnerability.

If an attacker obtains administrator credentials, those credentials may potentially be used to access additional systems.

This technique is commonly associated with lateral movement.

For example:

PC-01 compromised

↓

Administrator credentials stolen

↓

Credentials used against PC-02

↓

PC-02 compromised

↓

Additional servers or endpoints targeted

This is particularly dangerous when organizations reuse the same local administrator password across many computers.

7. Can Malware Spread Through Shared Folders?

Potentially, yes.

Malware may interact with writable network shares.

Depending on the malware, it could:

• Copy malicious files to shared locations
• Modify files
• Encrypt accessible files during ransomware attacks
• Replace legitimate files
• Create malicious shortcuts or executables

An important distinction is that malware being copied to a shared folder does not necessarily mean another computer is automatically infected. Infection generally requires the malicious content to be executed or another exploitation mechanism to succeed.

Ransomware is particularly dangerous because a compromised computer may encrypt files on network shares accessible using the victim's credentials.

8. Can Malware Spread Through USB Drives?

Yes.

Removable storage has historically been an important malware transmission mechanism.

An infected system may place malicious files on a USB drive. If those files are subsequently executed on another computer, the second computer may become infected.

Modern versions of Windows include security improvements that reduce some historical AutoRun-related risks, but users should still treat unknown removable storage cautiously.

9. How to Prevent Malware From Spreading Across a Network

Businesses should use multiple security layers.

Important protections include:

• Keep Windows and applications updated
• Install endpoint protection
• Enable firewalls
• Disable unnecessary network services
• Restrict administrative privileges
• Use unique local administrator credentials
• Implement MFA for remote and privileged access
• Segment networks where appropriate
• Restrict SMB/network share permissions
• Secure Remote Desktop access
• Monitor unusual authentication activity
• Maintain tested backups
• Use endpoint detection and response (EDR) where appropriate
• Remove obsolete systems
• Patch servers promptly
• Restrict unnecessary executable files
• Apply least-privilege principles

Network segmentation is especially useful because it can limit an attacker's ability to move freely after one device is compromised.

10. Can Malware Infect Smartphones and Tablets?

Yes.

Smartphones and tablets are computers and can be targeted by malicious software.

Mobile malware can affect devices running:

• Android
• iOS/iPadOS
• Other mobile operating systems

However, infection methods and practical risk vary significantly between platforms because their application models and security architectures differ.

11. Android Malware

Android devices can be targeted by malicious applications and other attacks.

Risk may increase when users:

• Install applications from untrusted sources
• Sideload unknown APK files
• Disable security protections
• Grant excessive permissions
• Use outdated Android versions
• Click malicious links
• Install fake applications
• Use modified or unofficial applications
• Root devices without understanding the security consequences

A malicious Android application may attempt to obtain access to sensitive information after receiving permissions or abusing vulnerabilities.

12. What Can Android Malware Do?

Depending on permissions, vulnerabilities, Android version, and security controls, malicious software may attempt to:

• Read notifications
• Access contacts
• Read or manipulate certain messages where permissions allow
• Record audio
• Access cameras
• Track location
• Display fraudulent overlays
• Capture credentials
• Steal files
• Monitor clipboard data
• Abuse accessibility services
• Download additional malicious components
• Intercept information used for authentication
• Spy on user activity

Android's security model limits what normal applications can access, so many malicious applications rely heavily on convincing victims to grant powerful permissions.

13. Mobile Banking Trojans

Mobile banking Trojans are designed specifically to target financial applications.

A malicious app may attempt to display a fake interface over or instead of a banking application.

The victim believes they are entering information into their bank's application, while the credentials are actually being captured by malware.

Some malicious applications also abuse Android accessibility features to monitor or control activity after convincing the victim to grant accessibility permissions.

Users should therefore be particularly cautious when an unfamiliar application requests accessibility access.

14. Can iPhones and iPads Get Malware?

Yes, although Apple's security architecture places substantial restrictions on applications.

iOS and iPadOS use mechanisms including:

• Application sandboxing
• Code-signing requirements
• Permission controls
• Application review
• Hardware-backed security features
• Rapid security and operating-system updates

These controls make many traditional malware techniques more difficult.

However, iPhones and iPads are not immune to cyberattacks.

Threats can include:

• Malicious or deceptive websites
• Phishing
• Credential theft
• Account compromise
• Exploitation of software vulnerabilities
• Highly targeted spyware
• Malicious configuration or management profiles
• Social engineering

Jailbreaking a device can also remove or weaken important platform security protections.

15. Malware vs Phishing on Smartphones

It is important to distinguish malware from phishing.

If you receive a fake banking SMS saying:

"Your account has been suspended. Click here to verify."

and you enter your credentials on a fake website, your password may be stolen even if the phone itself was never infected with malware.

Therefore:

Credential theft does not automatically mean malware infection.

Phishing, malicious websites, compromised accounts, and malware are separate attack methods, although attackers frequently combine them.

16. Warning Signs of Malware on a Computer

Possible indicators include:

• Computer suddenly becoming unusually slow
• Unexpected high CPU usage
• Unexplained network activity
• Antivirus being disabled
• Unknown startup applications
• Browser redirects
• Unexpected advertisements
• New browser extensions
• Unknown scheduled tasks
• Suspicious processes
• Files disappearing or being encrypted
• Security settings changing unexpectedly
• Unrecognized login activity
• Password reset notifications
• Unexpected account transactions

However, these symptoms do not prove malware is present. Hardware problems, software bugs, legitimate background processes, and configuration problems can cause similar behavior.

17. Warning Signs of Malware on Smartphones

Potential warning signs include:

• Unknown applications
• Unexpected pop-ups
• Excessive battery usage
• Abnormally high mobile-data usage
• Device overheating without obvious reason
• Unexpected permission requests
• Accessibility permissions enabled for unknown apps
• Browser redirects
• Unexplained SMS or notifications
• Security settings changed unexpectedly
• Banking or email accounts showing suspicious activity

Again, none of these symptoms alone confirms malware.

18. What Should You Do If You Suspect Password-Stealing Malware?

If you believe a computer or smartphone may contain credential-stealing malware, changing passwords immediately from the suspected device may not be sufficient.

The malware could potentially capture the new password.

A safer response is:

1. Disconnect or isolate the suspected device when appropriate.
2. Use a separate, trusted device.
3. Change passwords for critical accounts.
4. Prioritize email accounts because they are often used for password recovery.
5. Change financial and business-account credentials.
6. Enable or review MFA.
7. Sign out existing sessions where the service provides this option.
8. Review account login history.
9. Contact the bank promptly if financial compromise is suspected.
10. Scan and investigate the affected device.
11. Remove malicious applications or software.
12. Install operating-system and application updates.
13. Consider a clean operating-system reinstall if system integrity cannot be established.

For a business environment, preserve evidence and involve the IT/security team before aggressively deleting files if an incident investigation may be required.

19. Should You Change Passwords After Removing Malware?

Yes, if credential theft is possible.

A useful sequence is:

Contain Device → Investigate/Clean or Rebuild → Verify Device Security → Reset Credentials → Revoke Existing Sessions → Enable/Review MFA → Monitor Accounts

If credentials are changed before the compromised system is secured, they could potentially be stolen again.

20. Protecting Banking Information

For better financial security:

• Use official banking applications and websites
• Avoid banking through links received in unexpected messages
• Never install applications at the request of unknown callers
• Never share passwords, PINs, card CVVs, or authentication codes
• Enable transaction notifications
• Use MFA where available
• Keep devices updated
• Use reputable endpoint security where appropriate
• Review bank transactions regularly
• Avoid storing sensitive banking information in unprotected files
• Secure your primary email account
• Use strong, unique passwords
• Consider a reputable password manager
• Avoid rooting or jailbreaking devices used for banking

A compromised email account is particularly dangerous because email frequently acts as the recovery channel for other accounts.

21. Protecting a Business Network From Malware

Businesses require more than antivirus software.

A stronger architecture can include:

Internet

↓

Firewall / Security Gateway

↓

Segmented Network

↓

Servers + Workstations + Mobile Devices

↓

Endpoint Protection / EDR

↓

Centralized Monitoring + Backup

Important security controls include:

Endpoint Protection

Every workstation and server should have properly configured security protection.

Patch Management

Operating systems, browsers, productivity applications, server software, and third-party applications should receive security updates.

Least Privilege

Employees should not routinely use administrator accounts for normal work.

Network Segmentation

Servers, user computers, guest Wi-Fi, IoT equipment, and critical infrastructure should be separated where practical.

Backup

Maintain multiple backup copies, including backups that cannot be easily modified or encrypted from ordinary user accounts.

MFA

Protect cloud accounts, VPNs, remote access, administrator accounts, and other sensitive services with MFA wherever possible.

Monitoring

Organizations should monitor suspicious authentication, endpoint alerts, unusual network behavior, and unexpected privilege changes.

22. Antivirus Alone Is Not Enough

Antivirus remains important, but modern cybersecurity depends on defense in depth.

A stronger security strategy combines:

Antivirus/Endpoint Protection + Firewall + Updates + MFA + Strong Authentication + Least Privilege + Network Segmentation + Backup + User Awareness + Monitoring

No single security product can guarantee protection from every threat.

23. Home Network Example

Consider a home containing:

• Windows desktop
• Laptop
• Android smartphone
• iPhone
• Smart TV
• Wi-Fi router

If the Windows desktop becomes infected, it does not automatically mean every device is infected.

For malware to move to other systems, it generally needs an additional mechanism, such as a vulnerability, exposed service, weak or stolen credentials, unsafe file sharing, or user interaction.

Maintaining updated devices and securing the router therefore remain important.

24. Business Network Example

Consider an office with:

• 30 Windows computers
• Windows Server
• Shared folders
• Accounting software
• Remote Desktop
• Network printers
• NAS backup
• Internet-connected firewall

If one workstation is compromised, an attacker may attempt to discover other systems and move laterally.

Potential targets include:

Workstation → Shared Folders → Other Workstations → Server → Backup Storage

Proper access controls, endpoint protection, unique administrator credentials, segmentation, monitoring, and protected backups can significantly reduce this risk.

25. Key Technical Takeaways

Can malware steal passwords?

Yes.

Credential stealers, spyware, keyloggers, banking Trojans, and other malicious software can target passwords and authentication information.

Can malware steal banking information?

Yes.

Banking malware can target financial credentials, payment information, authenticated sessions, and transaction-related information.

Can malware spread across a local network?

Yes.

Worms and attackers controlling compromised machines can exploit vulnerabilities, credentials, network services, or unsafe shares to reach additional computers.

Does one infected computer automatically infect the whole network?

No.

Propagation requires an exploitable path or some other successful attack mechanism.

Can smartphones get malware?

Yes.

Android and iOS/iPadOS devices can be attacked, although their threat models and security architectures differ.

Is iPhone completely immune to malware?

No.

Apple devices have strong built-in security controls, but vulnerabilities, sophisticated spyware, phishing, account compromise, and social engineering remain possible.

Is Android automatically unsafe?

No.

Risk depends heavily on device support, security updates, application sources, permissions, configuration, and user behavior.

Frequently Asked Questions (FAQ)

1. Can malware see my saved passwords?

Potentially. Some information-stealing malware specifically targets browser and application credential stores. Whether it succeeds depends on the operating system, application, encryption, permissions, and malware capabilities.

2. Can malware steal my online banking password?

Yes. Banking Trojans, keyloggers, credential stealers, fake login pages, and other techniques can target online banking credentials.

3. Can malware steal passwords saved in Chrome or another browser?

Potentially. Browser passwords are protected rather than simply stored as plain text, but malware operating in a compromised user context may attempt to obtain credentials or abuse legitimate mechanisms available to that user.

4. Can malware bypass two-factor authentication?

Some attacks can undermine particular MFA workflows by stealing authenticated sessions, phishing authentication information, or tricking users into approving requests. MFA still provides important protection.

5. Can malware steal browser cookies?

Yes. Some information-stealing malware specifically targets browser cookies and authentication tokens.

6. Why are stolen cookies dangerous?

Some cookies represent authenticated sessions. If a service permits a stolen session to be reused, an attacker may gain access without entering the account password again.

7. Can malware spread through Wi-Fi?

Being connected to the same Wi-Fi does not itself cause infection. Malware may, however, use network access to discover and attack vulnerable or poorly secured devices.

8. Can malware spread through Ethernet?

Yes, if malware has a viable method to attack other network-connected systems. The physical connection being Ethernet rather than Wi-Fi is not the key issue.

9. Can malware infect another PC through a shared folder?

Potentially. Malware can place or modify files on writable shares, and ransomware can encrypt accessible network files. Additional execution or exploitation is generally required to infect another computer itself.

10. Can ransomware affect network drives?

Yes. Ransomware running under a user account may encrypt network locations accessible using that account's permissions.

11. Can malware infect a server from a workstation?

Yes. If an attacker or malware can exploit a vulnerable service, obtain suitable credentials, or abuse a configuration weakness, a compromised workstation may become a stepping stone toward a server.

12. Can malware spread automatically?

Some malware, particularly worms, is designed for automated propagation.

13. Can an Android phone get a virus?

Android devices can be infected with malicious software. "Malware" is generally the more accurate umbrella term because mobile threats include Trojans, spyware, stalkerware, banking malware, and other malicious applications.

14. Can an iPhone get malware?

Yes. iPhones have strong platform security, but they are not immune to software vulnerabilities, targeted spyware, malicious configurations, phishing, or account compromise.

15. Can malware steal OTP codes?

On a compromised device, malicious software with sufficient capabilities or permissions may attempt to access SMS messages, notifications, or other authentication information. Platform security controls can restrict such access.

16. Can malware record my screen?

Some spyware and remote-access malware can capture screenshots or screen information when it obtains the required privileges or permissions.

17. Can malware activate a microphone or camera?

Some malicious applications may attempt to access microphones or cameras if they obtain the necessary permissions or exploit a vulnerability.

18. Does antivirus detect every malware infection?

No. Security software substantially reduces risk but cannot guarantee detection of every malicious program or attack.

19. Should I change passwords immediately after discovering malware?

Use a separate trusted device for urgent password changes. Secure or rebuild the compromised device before trusting it with new credentials.

20. Which password should I change first after an infection?

Your primary email account is usually one of the highest priorities because it often controls password recovery for many other accounts. Financial, administrator, cloud, and business accounts should also receive immediate attention based on risk.

21. Should I reinstall Windows after a serious malware infection?

For severe infections, credential-stealing malware, rootkits, or cases where system integrity cannot be confidently established, a clean installation may be safer than relying solely on malware removal.

22. Can malware come back after antivirus removes it?

Yes, particularly if persistence mechanisms, secondary malware, compromised credentials, vulnerable software, or the original infection source remain.

23. Can a factory reset remove smartphone malware?

A factory reset can remove many ordinary malicious applications, but account compromise and cloud-side issues require separate remediation. Rare, sophisticated threats may require additional investigation.

24. Can malware infect my router?

Routers and other network devices can also contain vulnerabilities or be compromised through weak credentials. Router firmware should be kept updated and administrative passwords should be changed from defaults.

25. What is the best defense against malware?

There is no single defense. The strongest practical approach combines updated software, endpoint protection, secure authentication, MFA, least privilege, network security, backups, monitoring, and cautious user behavior.

Conclusion

Modern malware is capable of much more than damaging files.

It can potentially steal passwords, banking information, browser sessions, authentication information, and confidential business data. Certain malware and attacker-controlled systems can also move laterally across networks when vulnerabilities, credentials, or insecure configurations provide a path.

Smartphones and tablets must also be considered part of an organization's or individual's cybersecurity perimeter.

The most effective defense is therefore not a single antivirus application but a layered security strategy:

Protect the Device → Protect Credentials → Protect the Network → Protect Accounts → Protect Backups → Monitor for Compromise

For businesses, combining endpoint protection, patch management, MFA, least privilege, network segmentation, protected backups, and security monitoring substantially improves resilience against modern malware.

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