ClamAV is an open-source antivirus engine for detecting trojans, viruses, malware & other malicious threats. It features a command line interface for scanning files, updating the virus definitions, and a daemon for faster scanning needed on high performance systems.

Unlike most antivirus products, ClamAV requires no yearly subscription fee, and is completely free with source code to anyone who wishes to use it. Because ClamAV is released under the GPL v2 license, you must follow all license requirements if you modify the ClamAV source code, or use it in your own projects.

What's New

ClamAV 1.2.0 includes the following improvements and changes:

Major changes

  • Added support for extracting Universal Disk Format (UDF) partitions.
  • Specifically, this version adds support for the Beginning Extended Area Descriptor (BEA01) type of UDF files.
    • GitHub pull request: https://github.com/Cisco-Talos/clamav/pull/941
  • Added an option to customize the size of ClamAV's clean file cache.
  • Increasing the size of the clean file cache may improve scan performance but will require more RAM. The cache size value should be a square number or will be rounded up to the nearest square number.
  • The cache size option for clamd and clamscan is --cache-size. Alternatively, you can customize the cache size for ClamD by setting CacheSize in clamd.conf.
  • Patch courtesy of Craig Andrews.
    • GitHub pull request: https://github.com/Cisco-Talos/clamav/pull/882
  • Introduced a SystemD timer for running Freshclam updates, without sending Freshclam into the background. This takes the "burden of timing the updates" from Freshclam and puts it onto SystemD. The timer can be activated, audited, and the logs inspected:
  • sudo systemctl enable --now clamav-freshclam-once.timer sudo systemctl list-timers sudo systemctl status clamav-freshclam-once.timer sudo systemctl status clamav-freshclam-once.service journalctl -u clamav-freshclam-once.service
  • If you want a different update interval you can edit the timer unit file:
  • sudo systemctl edit clamav-freshclam-once.timer
  • Patch courtesy of Nils Werner.
    • GitHub pull request: https://github.com/Cisco-Talos/clamav/pull/962
  • Raised the MaxScanSize limit so the total amount of data scanned when scanning a file or archive may exceed 4 gigabytes.
  • Introduced the ability to suffix the MaxScanSize and other config file size options with a "G" or "g" for the number of gigabytes. For example, for ClamD you may now specify MaxScanSize 10G in clamd.conf. And for ClamScan, you may now specify --max-scansize=10g.
  • The MaxFileSize is still limited internally in ClamAV to 2 gigabytes. Any file, or embedded file, larger than 2GB will be skipped. You may use clamscan --alert-exceeds-max, or the clamd.conf option AlertExceedsMax yes to tell if a scan is not completed because of the scan limits.
  • Patch courtesy of matthias-fratz-bsz.
    • GitHub pull request: https://github.com/Cisco-Talos/clamav/pull/945
  • Added ability for Freshclam to use a client certificate PEM file and a private key PEM file for authentication to a private mirror by setting the following environment variables:
    • FRESHCLAM_CLIENT_CERT: May be set to the path of a file (PEM) containing the client certificate.
    • FRESHCLAM_CLIENT_KEY: May be set to the path of a file (PEM) containing the client private key.
    • FRESHCLAM_CLIENT_KEY_PASSWD: May be set to a password for the client key PEM file, if it is password protected.
  • Patch courtesy of jedrzej.
    • GitHub pull request: https://github.com/Cisco-Talos/clamav/pull/955

Other improvements

  • Fix an issue extracting files from ISO9660 partitions where the files are listed in the plain ISO tree and there also exists an empty Joliet tree.
    • GitHub pull request: https://github.com/Cisco-Talos/clamav/pull/938
  • CMake build system improvement to support compiling with OpenSSL 3.x on macOS with the Xcode toolchain.
  • The official ClamAV installers and packages are now built with OpenSSL 3.1.1 or newer.
    • GitHub pull request: https://github.com/Cisco-Talos/clamav/pull/970
  • The suggested path for the clamd.pid and clamd.sock file in the sample configs have been updated to reflect the recommended locations for these files in the Docker images. These are:
    • /run/clamav/clamd.pid
    • /run/clamav/clamd.sock
  • For consistency, it now specifies clamd.sock instead of clamd.socket.
  • Patch courtesy of computersalat.
    • GitHub pull request: https://github.com/Cisco-Talos/clamav/pull/931

Bug fixes

  • Fixed an issue where ClamAV does not abort the signature load process after partially loading an invalid signature. The bug would later cause a crash when scanning certain files.
    • GitHub pull request: https://github.com/Cisco-Talos/clamav/pull/934
  • Fixed a possible buffer over-read bug when unpacking PE files.
    • GitHub pull request: https://github.com/Cisco-Talos/clamav/pull/927
  • Removed a warning message showing the HTTP response codes during the Freshclam database update process.
    • GitHub pull request: https://github.com/Cisco-Talos/clamav/pull/935
  • Added missing command line options to the ClamD and ClamAV-Milter --help message and manpages.
    • GitHub pull request: https://github.com/Cisco-Talos/clamav/pull/936
  • ClamOnAcc: Fixed error message when using --wait without --ping option. Patch courtesy of RÄzvan Cojocaru.
    • GitHub pull request: https://github.com/Cisco-Talos/clamav/pull/984
  • Fixed an assortment of code quality issues identified by Coverity
  • Updated to Sigtool so that the --vba option will extract VBA code from Microsoft Office documents the same way that libclamav extracts VBA. This resolves several issues where Sigtool could not extract VBA. Sigtool will also now display the normalized VBA code instead of the pre-normalized VBA code.
    • GitHub pull request: https://github.com/Cisco-Talos/clamav/pull/852
  • Added a new ClamScan and ClamD option: --fail-if-cvd-older-than=days. Additionally, we introduce FailIfCvdOlderThan as a clamd.conf synonym for --fail-if-cvd-older-than. When passed, it causes ClamD to exit on startup with a non-zero return code if the virus database is older than the specified number of days.
    • GitHub pull request: https://github.com/Cisco-Talos/clamav/pull/867
  • Added a new function cl_cvdgetage() to the libclamav API. This function will retrieve the age in seconds of the youngest file in a database directory, or the age of a single CVD (or CLD) file.
    • GitHub pull request: https://github.com/Cisco-Talos/clamav/pull/867
  • Added a new function cl_engine_set_clcb_vba() to the libclamav API. Use this function to set a cb_vba callback function. The cb_vba callback function will be run whenever VBA is extracted from office documents. The provided data will be a normalized copy of the extracted VBA. This callback was added to support Sigtool so that it can use the same VBA extraction logic that ClamAV uses to scan documents.
    • GitHub pull request: https://github.com/Cisco-Talos/clamav/pull/852

Other improvements

  • Removed the vendored TomsFastMath library in favor of using OpenSSL to perform "big number"/multiprecision math operations. Work courtesy of Sebastian Andrzej Siewior.
    • GitHub pull request: https://github.com/Cisco-Talos/clamav/pull/840
  • Build system: Added CMake option DO_NOT_SET_RPATH to avoid setting RPATH on Unix systems. Feature courtesy of Sebastian Andrzej Siewior.
    • GitHub pull request: https://github.com/Cisco-Talos/clamav/pull/815
  • Build system: Enabled version-scripts with CMake to limit symbol exports for libclamav, libfreshclam, libclamunrar_iface, and libclamunrar shared libraries on Unix systems, excluding macOS. Improvement courtesy of Orion Poplawski and Sebastian Andrzej Siewior.
    • GitHub pull request: https://github.com/Cisco-Talos/clamav/pull/776
  • Build system: Enabled users to pass in custom Rust compiler flags using the RUSTFLAGS CMake variable. Feature courtesy of Orion Poplawski.
    • GitHub pull request: https://github.com/Cisco-Talos/clamav/pull/835
  • Removed a hard-coded alert for CVE-2004-0597. The CVE is old enough that it is no longer a threat and the detection had occasional false-positives.
    • GitHub pull request: https://github.com/Cisco-Talos/clamav/pull/855
  • Set Git attributes to prevent Git from altering line endings for Rust vendored libraries. Third-party Rust libraries are bundled in the ClamAV release tarball. We do not commit them to our own Git repository, but community package maintainers may now store the tarball contents in Git. The Rust build system verifies the library manifest, and this change ensures that the hashes are correct. Improvement courtesy of Nicolas R.
    • GitHub pull request: https://github.com/Cisco-Talos/clamav/pull/800
  • Fixed compile time warnings. Improvement courtesy of RÄzvan Cojocaru.
    • GitHub pull request: https://github.com/Cisco-Talos/clamav/pull/795
  • Added a minor optimization when matching domain name regex signatures for PDB, WDB and CDB type signatures.
    • GitHub pull request: https://github.com/Cisco-Talos/clamav/pull/837
  • Build system: Enabled the ability to select a specific Python version. When building, you may use the CMake option -D PYTHON_FIND_VER= to choose a specific Python version. Feature courtesy of Matt Jolly.
    • GitHub pull request: https://github.com/Cisco-Talos/clamav/pull/787
  • Added improvements to the ClamOnAcc process log output so that it is easier to diagnose bugs.
    • GitHub pull request: https://github.com/Cisco-Talos/clamav/pull/822
  • Windows: Enabled the MSI installer to upgrade between feature versions more easily when ClamAV is installed to a location different from the default (i.e., not C:\Program Files\ClamAV). This means that the MSI installer can find a previous ClamAV 1.0.x installation to upgrade to ClamAV 1.1.0.
    • GitHub pull request: https://github.com/Cisco-Talos/clamav/pull/872
  • Sigtool: Added the ability to change the location of the temp directory using the --tempdir option and added the ability to retain the temp files created by Sigtool using the --leave-temps option.
    • GitHub pull request: https://github.com/Cisco-Talos/clamav/pull/852

Other minor improvements.

Bug fixes

  • Fixed the broken ExcludePUA / --exclude-pua feature. Fix courtesy of Ged Haywood and Shawn Iverson.
    • GitHub pull request: https://github.com/Cisco-Talos/clamav/pull/780
  • Fixed an issue with integer endianness when parsing Windows executables on big-endian systems. Fix courtesy of Sebastian Andrzej Siewior.
    • GitHub pull request: https://github.com/Cisco-Talos/clamav/pull/814
  • Fixed a possible stack overflow read when parsing WDB signatures. This issue is not a vulnerability.
    • GitHub pull request: https://github.com/Cisco-Talos/clamav/pull/807
  • Fixed a possible index out of bounds when loading CRB signatures. This issue is not a vulnerability.
    • GitHub pull request: https://github.com/Cisco-Talos/clamav/pull/810
  • Fixed a possible use after free when reading logical signatures. This issue is not a vulnerability.
    • GitHub pull request: https://github.com/Cisco-Talos/clamav/pull/811
  • Fixed a possible heap overflow read when reading PDB signatures. This issue is not a vulnerability.
    • GitHub pull request: https://github.com/Cisco-Talos/clamav/pull/812
  • Fixed a possible heap overflow read in javascript normalizer module. This issue is not a vulnerability.
    • GitHub pull request: https://github.com/Cisco-Talos/clamav/pull/868
  • Fixed two bugs that would cause Freshclam to fail update when applying a CDIFF database patch if that patch adds a file to the database archive or removes a file from the database archive. This bug also caused Sigtool to fail to create such a patch.
    • GitHub pull request: https://github.com/Cisco-Talos/clamav/pull/893
  • Fixed an assortment of complaints identified by Coverity static analysis.

GitHub pull requests:

  • https://github.com/Cisco-Talos/clamav/pull/891
  • https://github.com/Cisco-Talos/clamav/pull/899
  • Fixed one of the Freshclam tests that was failing on some Fedora systems due to a bug printing debug-level log messages to stdout. Fix courtesy of Arjen de Korte.
  • GitHub pull request: https://github.com/Cisco-Talos/clamav/pull/881
  • Correctly remove temporary files generated by the VBA and XLM extraction modules so that the files are not leaked in patched versions of ClamAV where temporary files are written directly to the temp-directory instead of writing to a unique subdirectory.
  • GitHub pull request: https://github.com/Cisco-Talos/clamav/pull/894