ClamAV
ClamAV 1.5.3 is an open-source antivirus engine for detecting malware, with clamscan, clamd, clamdscan, freshclam and Linux on-access components.
What ClamAV provides
ClamAV is an antivirus engine and toolset for mail gateways, upload folders, file servers, automation pipelines and on-demand desktop scans. It offers signature updates, command-line scanning and a long-running clamd service, but deployment still requires explicit scheduling, permissions, quarantine, alerting and resource limits.
Detection and resource boundaries
A clean result means that the current engine, signature database and scan limits found no match; it does not prove that a file is trustworthy. Encrypted archives, oversized objects and parser errors require a separate status. Recursive extraction, temporary space and scan-time limits reduce resource exhaustion but can leave files unscanned.
Version and licensing notes
ClamAV 1.5.3 includes fixes for several parser, archive and temporary-space issues across supported platforms. Keep the engine and signature date together in audit records. The main project uses GPL-2.0, while optional components may have their own license terms. Review date: 2026-08-23.
Save to your cloud drive
Open the cloud drive to get the file directly, or save it for convenient access on another device.
Quark Cloud Drive
RecommendedSave ClamAV to this cloud drive
Baidu Netdisk
Save ClamAV to this cloud drive
ClamAV 1.5.3 signature update and isolated scan guide
Update signatures, scan a small non-sensitive test directory, review detections and errors, and place confirmed items in a restricted quarantine rather than deleting them automatically.
Before you start
- Select a supported 1.5.3 build or a maintained release with the relevant security fixes.
- Prepare a normal-user test directory, a separate restricted quarantine directory and enough temporary disk space.
- Back up important data and test mail, upload or shared folders during a maintenance window.
Installation steps
- 01
Select the platform package
Choose the Windows MSI or ZIP, macOS PKG, Linux DEB, RPM or TAR.GZ, or a container image that matches the host architecture.
- 02
Update the signature database
Run freshclam for the first update and check the database timestamp, mirror errors, directory permissions and update schedule before scanning.
- 03
Set least-privilege service paths
Give clamd, its cache, logs and quarantine separate permissions. The scanner needs read access to targets but should not receive unrestricted system write access.
Quick start
- 01
Scan a small test folder
Run a recursive scan and save the log, checking scanned files, skipped objects, errors, limits and detections rather than reading only the final line.
- 02
Review detections and false positives
Record the path, hash, signature name and source without executing the sample. Use multiple signals before deciding whether an internal file is a false positive.
- 03
Add service and alert controls
Enable clamd, scheduled freshclam or on-access monitoring only after the test succeeds; configure resource limits, stale-signature alerts and a notification test.
Usage tips
- Keep the engine version, signature date, scan limits and log with every operational result.
- A file skipped because of size, encryption or parser error must be labeled unscanned rather than safe.
- ClamAV complements least privilege, patching, sandboxing and recoverable backups; it is not a complete endpoint suite by itself.
Troubleshooting and uninstall
Why does freshclam fail or report an old database?
Check DNS, proxy settings, system time, database permissions and update frequency, and avoid multiple instances writing the same directory. Re-scan after a successful update.
Why does scanning a large archive exhaust disk space?
Stop the job, clean the controlled temporary directory and set archive size, recursion and time limits. Mark the affected object as incompletely scanned.
- Stop services and retain recordsStop clamd, on-access monitoring and scheduled updates, then keep the required engine, signature, detection and disposition records.
- Process the database and quarantineRemove caches and signatures only when no longer needed. Handle quarantined samples through the established malware process and never restore them into an ordinary executable folder.
Frequently asked questions
Does installing ClamAV automatically protect the whole computer in real time?
No. ClamAV supplies the engine and tools; signature updates, clamd, on-access monitoring, schedules and alerts must be configured for the platform.
Does a clean scan prove that a file is safe?
No. Current signatures, parser limits, encrypted archives and skipped objects affect the result. Combine scan output with source, behavior, patch and isolation evidence.
Does the download require an extraction code?
The Quark entry does not require one; the four-character code for the Baidu entry is shown beside its download entry.