clamd.conf(5)

NAME

clamd.conf - Configuration file for Clam AntiVirus Daemon

DESCRIPTION

clamd.conf configures the Clam AntiVirus daemon, clamd(8).

FILE FORMAT
The file consists of comments and options with arguments. Each line which starts with a hash (#) symbol is ignored by the parser. Options and arguments are case sensitive and of the form Option Argument. The arguments are of the following types:

BOOL
    Boolean value (yes/no or true/false or 1/0).

STRING
    String without blank characters.

SIZE
    Size in bytes. You can use 'M' or 'm' modifiers for megabytes and 'K' or 'k' for kilobytes. To specify the size in bytes just don't use modifiers.

NUMBER
    Unsigned integer.

DIRECTIVES

When some option is not used (commented out or not included in the configuration file at all) clamd takes a default action.

Example
    If this option is set clamd will not run.

LogFile STRING
    Save all reports to a log file.
    Default: disabled

LogFileUnlock BOOL
    By default the log file is locked for writing and only a single daemon process can write to it. This option disables the lock.
    Default: no

LogFileMaxSize SIZE
    Maximum size of the log file.
    Value of 0 disables the limit.
    Default: 1048576

LogTime BOOL
    Log time for each message.
    Default: no

LogClean BOOL
    Log all clean files.
    Useful in debugging but drastically increases the log size.
    Default: no

LogSyslog BOOL
    Use the system logger (can work together with LogFile).
    Default: no

LogFacility STRING
    Type of syslog messages
    Please refer to 'man syslog' for facility names.
    Default: LOG_LOCAL6

LogVerbose BOOL
    Enable verbose logging.
    Default: no

LogRotate BOOL
    Rotate log file. Requires LogFileMaxSize option set prior to this option.
    Default: no

ExtendedDetectionInfo BOOL
    Log additional information about the infected file, such as its size and hash, together with the virus name.
    Default: no

PidFile STRING
    Save the process identifier of a listening daemon (main thread) to a specified file.
    Default: disabled

TemporaryDirectory STRING
    This option allows you to change the default temporary directory.
    Default: system specific (usually /tmp or /var/tmp).

DatabaseDirectory STRING
    This option allows you to change the default database directory. If you enable it, please make sure it points to the same directory in both clamd and freshclam.
    Default: defined at configuration (/usr/local/share/clamav)

OfficialDatabaseOnly BOOL
    Only load the official signatures published by the ClamAV project.
    Default: no

LocalSocket STRING
    Path to a local (Unix) socket the daemon will listen on.
    Default: disabled

LocalSocketGroup STRING
    Sets the group ownership on the unix socket.
    Default: the primary group of the user running clamd

LocalSocketMode STRING
    Sets the permissions on the unix socket to the specified mode.
    Default: socket is world readable and writable

FixStaleSocket BOOL
    Remove stale socket after unclean shutdown.
    Default: yes

TCPSocket NUMBER
    TCP port number the daemon will listen on.
    Default: disabled

TCPAddr STRING
    By default clamd binds to INADDR_ANY.
    This option allows you to restrict the TCP address and provide some degree of protection from the outside world. This option can be specified multiple times in order to listen on multiple IPs. IPv6 is now supported.
    Default: disabled

MaxConnectionQueueLength NUMBER
    Maximum length the queue of pending connections may grow to.
    Default: 200

StreamMaxLength SIZE
    Close the STREAM session when the data size limit is exceeded.
    The value should match your MTA's limit for the maximum attachment size.
    Default: 25M

StreamMinPort NUMBER
    The STREAM command uses an FTP-like protocol.
    This option sets the lower boundary for the port range.
    Default: 1024

StreamMaxPort NUMBER
    This option sets the upper boundary for the port range.
    Default: 2048

MaxThreads NUMBER
    Maximum number of threads running at the same time.
    Default: 10

ReadTimeout NUMBER
    This option specifies the time (in seconds) after which clamd should timeout if a client doesn't provide any data.
    Default: 120

CommandReadTimeout NUMBER
    This option specifies the time (in seconds) after which clamd should timeout if a client doesn't provide any initial command after connecting. Note: the timeout for subsequents commands, and/or data chunks is specified by ReadTimeout.
    Default: 5

SendBufTimeout NUMBER
    This option specifies how long to wait (in milliseconds) if the send buffer is full. Keep this value low to prevent clamd hanging.
    Default: 500

MaxQueue NUMBER
    Maximum number of queued items (including those being processed by MaxThreads threads). It is recommended to have this value at least twice MaxThreads if possible.
    WARNING: you shouldn't increase this too much to avoid running out of file descriptors, the following condition should hold: MaxThreads*MaxRecursion + MaxQueue - MaxThreads + 6 < RLIMIT_NOFILE. RLIMIT_NOFILE is the maximum number of open file descriptors (usually 1024), set by ulimit -n.
    Default: 100

IdleTimeout NUMBER
    This option specifies how long (in seconds) the process should wait for a new job.
    Default: 30

ExcludePath REGEX
    Don't scan files and directories matching REGEX. This directive can be used multiple times.
    Default: disabled

MaxDirectoryRecursion NUMBER
    Maximum depth directories are scanned at.
    Default: 15

FollowDirectorySymlinks BOOL
    Follow directory symlinks.
    Default: no

CrossFilesystems BOOL
    Scan files and directories on other filesystems.
    Default: yes

FollowFileSymlinks BOOL
    Follow regular file symlinks.
    Default: no

SelfCheck NUMBER
    This option specifies the time intervals (in seconds) in which clamd should perform a database check.
    Default: 600

VirusEvent COMMAND
    Execute a command when a virus is found. In the command string %v will be replaced with the virus name. Additionally, two environment variables will be defined: $CLAM_VIRUSEVENT_FILENAME and $CLAM_VIRUSEVENT_VIRUSNAME.
    Default: disabled

ExitOnOOM BOOL
    Stop daemon when libclamav reports out of memory condition.
    Default: no

AllowAllMatchScan BOOL
    Permit use of the ALLMATCHSCAN command.
    Default: yes

Foreground BOOL
    Don't fork into background.
    Default: no

Debug BOOL
    Enable debug messages from libclamav.
    Default: no

LeaveTemporaryFiles BOOL
    Do not remove temporary files (for debugging purpose).
    Default: no

User STRING
    Run the daemon as a specified user (the process must be started by root).
    Default: disabled

AllowSupplementaryGroups BOOL
    Initialize a supplementary group access (the process must be started by root).
    Default: no

Bytecode BOOL
    With this option enabled ClamAV will load bytecode from the database. It is highly recommended you keep this option turned on, otherwise you may miss detections for many new viruses.
    Default: yes

BytecodeSecurity STRING
    Set bytecode security level.
    Possible values:
    TrustSigned - trust bytecode loaded from signed .c[lv]d files and insert runtime safety checks for bytecode loaded from other sources,
    Paranoid - don't trust any bytecode, insert runtime checks for all.
    Recommended: TrustSigned, because bytecode in .cvd files already has these checks.
    Default: TrustSigned

BytecodeTimeout NUMBER
    Set bytecode timeout in milliseconds.
    Default: 5000

BytecodeUnsigned BOOL
    Allow loading bytecode from outside digitally signed .c[lv]d files.
    Default: no

BytecodeMode STRING
    Set bytecode execution mode.
    Possible values:
    Auto - automatically choose JIT if possible, fallback to interpreter
    ForceJIT - always choose JIT, fail if not possible
    ForceInterpreter - always choose interpreter
    Test - run with both JIT and interpreter and compare results. Make all failures fatal.
    Default: Auto

DetectPUA BOOL
    Detect Possibly Unwanted Applications.
    Default: No

ExcludePUA CATEGORY
    Exclude a specific PUA category. This directive can be used multiple times. See http://www.clamav.net/doc/pua.html for the complete list of PUA categories.
    Default: disabled

IncludePUA CATEGORY
    Only include a specific PUA category. This directive can be used multiple times. See http://www.clamav.net/doc/pua.html for the complete list of PUA categories.
    Default: disabled

AlgorithmicDetection BOOL
    In some cases (eg. complex malware, exploits in graphic files, and others), ClamAV uses special algorithms to provide accurate detection. This option controls the algorithmic detection.
    Default: yes

ScanPE BOOL
    PE stands for Portable Executable - it's an executable file format used in all 32 and 64-bit versions of Windows operating systems. This option allows ClamAV to perform a deeper analysis of executable files and it's also required for decompression of popular executable packers such as UPX.
    If you turn off this option, the original files will still be scanned, but without additional processing.
    Default: yes

ScanELF BOOL
    Executable and Linking Format is a standard format for UN*X executables. This option allows you to control the scanning of ELF files.
    If you turn off this option, the original files will still be scanned, but without additional processing.
    Default: yes

DetectBrokenExecutables BOOL
    With this option clamd will try to detect broken executables (both PE and ELF) and mark them as Broken.Executable.
    Default: no

ScanMail BOOL
    Enable scanning of mail files.
    If you turn off this option, the original files will still be scanned, but without parsing individual messages/attachments.
    Default: yes

ScanPartialMessages BOOL
    Scan RFC1341 messages split over many emails. You will need to periodically clean up $TemporaryDirectory/clamav-partial directory. WARNING: This option may open your system to a DoS attack. Never use it on loaded servers.
    Default: no

PhishingSignatures BOOL
    With this option enabled ClamAV will try to detect phishing attempts by using signatures.
    Default: yes

PhishingScanURLs BOOL
    Scan URLs found in mails for phishing attempts using heuristics. This will classify "Possibly Unwanted" phishing emails as Phishing.Heuristics.Email.*
    Default: yes

PhishingAlwaysBlockCloak BOOL
    Always block cloaked URLs, even if URL isn't in database. This can lead to false positives.
    Default: no

PhishingAlwaysBlockSSLMismatch BOOL
    Always block SSL mismatches in URLs, even if the URL isn't in the database. This can lead to false positives.
    Default: no

PartitionIntersection BOOL
    Detect partition intersections in raw disk images using heuristics.
    Default: no

HeuristicScanPrecedence BOOL
    Allow heuristic match to take precedence. When enabled, if a heuristic scan (such as phishingScan) detects a possible virus/phishing it will stop scanning immediately. Recommended, saves CPU scan-time. When disabled, virus/phishing detected by heuristic scans will be reported only at the end of a scan. If an archive contains both a heuristically detected virus/phishing, and a real malware, the real malware will be reported. Keep this disabled if you intend to handle "*.Heuristics.*" viruses differently from "real" malware. If a non-heuristically-detected virus (signature-based) is found first, the scan is interrupted immediately, regardless of this config option.
    Default: no

StructuredDataDetection BOOL
    Enable the DLP module.
    Default: no

StructuredMinCreditCardCount NUMBER
    This option sets the lowest number of Credit Card numbers found in a file to generate a detect.
    Default: 3

StructuredMinSSNCount NUMBER
    This option sets the lowest number of Social Security Numbers found in a file to generate a detect.
    Default: 3

StructuredSSNFormatNormal BOOL
    With this option enabled the DLP module will search for valid SSNs formatted as xxx-yy-zzzz.
    Default: Yes

StructuredSSNFormatStripped BOOL
    With this option enabled the DLP module will search for valid SSNs formatted as xxxyyzzzz.
    Default: No

ScanHTML BOOL
    Perform HTML/JavaScript/ScriptEncoder normalisation and decryption.
    If you turn off this option, the original files will still be scanned, but without additional processing.
    Default: yes

ScanOLE2 BOOL
    This option enables scanning of OLE2 files, such as Microsoft Office documents and .msi files.
    If you turn off this option, the original files will still be scanned, but without additional processing.
    Default: yes

OLE2BlockMacros BOOL
    With this option enabled OLE2 files with VBA macros, which were not detected by signatures will be marked as "Heuristics.OLE2.ContainsMacros".
    Default: no

ScanPDF BOOL
    This option enables scanning within PDF files.
    If you turn off this option, the original files will still be scanned, but without additional processing.
    Default: yes

ScanSWF BOOL
    This option enables scanning within SWF files.
    If you turn off this option, the original files will still be scanned, but without decoding and additional processing.
    Default: yes

ScanArchive BOOL
    Scan within archives and compressed files.
    If you turn off this option, the original files will still be scanned, but without unpacking and additional processing.
    Default: yes

ArchiveBlockEncrypted BOOL
    Mark encrypted archives as viruses (Encrypted.Zip, Encrypted.RAR).
    Default: no

ForceToDisk
    This option causes memory or nested map scans to dump the content to disk.
    If you turn on this option, more data is written to disk and is available when the leave-temps option is enabled at the cost of more disk writes.
    Default: no
    Default: no

MaxScanSize SIZE
    Sets the maximum amount of data to be scanned for each input file. Archives and other containers are recursively extracted and scanned up to this value. The size of an archive plus the sum of the sizes of all files within archive count toward the scan size. For example, a 1M uncompressed archive containing a single 1M inner file counts as 2M toward the max scan size. Warning: disabling this limit or setting it too high may result in severe damage to the system.
    Default: 100M

MaxFileSize SIZE
    Files larger than this limit won't be scanned. Affects the input file itself as well as files contained inside it (when the input file is an archive, a document or some other kind of container). Warning: disabling this limit or setting it too high may result in severe damage to the system.
    Default: 25M

MaxRecursion NUMBER
    Nested archives are scanned recursively, e.g. if a Zip archive contains a RAR file, all files within it will also be scanned. This options specifies how deeply the process should be continued. Warning: setting this limit too high may result in severe damage to the system.
    Default: 16

MaxFiles NUMBER
    Number of files to be scanned within an archive, a document, or any other kind of container. Warning: disabling this limit or setting it too high may result in severe damage to the system.
    Default: 10000

MaxEmbeddedPE SIZE
    This option sets the maximum size of a file to check for embedded PE.
    Files larger than this value will skip the additional analysis step.
    Negative values are not allowed.
    Default: 10M

MaxHTMLNormalize SIZE
    This option sets the maximum size of a HTML file to normalize.
    HTML files larger than this value will not be normalized or scanned.
    Negative values are not allowed.
    Default: 10M

MaxHTMLNoTags SIZE
    This option sets the maximum size of a normalized HTML file to scan.
    HTML files larger than this value after normalization will not be scanned.
    Negative values are not allowed.
    Default: 2M

MaxScriptNormalize SIZE
    This option sets the maximum size of a script file to normalize.
    Script content larger than this value will not be normalized or scanned.
    Negative values are not allowed.
    Default: 5M

MaxZipTypeRcg SIZE
    This option sets the maximum size of a ZIP file to reanalyze type recognition.
    ZIP files larger than this value will skip the step to potentially reanalyze as PE.
    Negative values are not allowed.
    WARNING: setting this limit too high may result in severe damage or impact performance.
    Default: 1M

MaxPartitions SIZE
    This option sets the maximum number of partitions of a raw disk image to be scanned.
    Raw disk images with more partitions than this value will have up to the value partitions scanned.
    Negative values are not allowed.
    WARNING: setting this limit too high may result in severe damage or impact performance.
    Default: 50

MaxIconsPE SIZE
    This option sets the maximum number of icons within a PE to be scanned.
    PE files with more icons than this value will have up to the value number icons scanned.
    Negative values are not allowed.
    WARNING: setting this limit too high may result in severe damage or impact performance.
    Default: 100

PCREMatchLimit NUMBER
    This option sets the maximum calls to the PCRE match function during an instance of regex matching.
    Instances using more than this limit will be terminated and alert the user but the scan will continue.
    For more information on match_limit, see the PCRE documentation.
    Negative values are not allowed.
    WARNING: setting this limit too high may severely impact performance.
    Default: 10000

PCRERecMatchLimit NUMBER
    This option sets the maximum recursive calls to the PCRE match function during an instance of regex matching.
    Instances using more than this limit will be terminated and alert the user but the scan will continue.
    For more information on match_limit_recursion, see the PCRE documentation.
    Negative values are not allowed and values > PCREMatchLimit are superfluous.
    WARNING: setting this limit too high may severely impact performance.
    Default: 5000

PCREMaxFileSize SIZE
    This option sets the maximum filesize for which PCRE subsigs will be executed.
    Files exceeding this limit will not have PCRE subsigs executed unless a subsig is encompassed to a smaller buffer.
    Negative values are not allowed.
    Setting this value to zero disables the limit.
    WARNING: setting this limit too high or disabling it may severely impact performance.
    Default: 25M

ScanOnAccess BOOL
    This option enables on-access scanning (Linux only)
    Default: disabled

OnAccessIncludePath STRING
    This option specifies a directory (including all files and directories inside it), which should be scanned on access. This option can be used multiple times.
    Default: disabled

OnAccessExcludePath STRING
    This option allows excluding directories from on-access scanning. It can be used multiple times.
    Default: disabled

OnAccessExcludeUID NUMBER
    With this option you can whitelist specific UIDs. Processes with these UIDs will be able to access all files.
    This option can be used multiple times (one per line).
    Default: disabled

OnAccessMaxFileSize SIZE
    Files larger than this value will not be scanned in on access.
    Default: 5M

OnAccessMountPath STRING
    Specifies a mount point (including all files and directories under it), which should be scanned on access. This option can be used multiple times.
    Default: disabled

OnAccessDisableDDD BOOL
    Disables the dynamic directory determination system which allows for recursively watching include paths.
    Default: no

OnAccessPrevention BOOL
    Enables fanotify blocking when malicious files are found.
    Default: disabled

DisableCertCheck BOOL
    Disable authenticode certificate chain verification in PE files.
    Default: no

StatsEnabled BOOL
    Enable submission of statistical data
    Default: no

StatsHostID STRING
    HostID in the form of an UUID to use when submitting statistical information.
    Default: auto

StatsPEDisabled BOOL
    Disable submission of PE section statistical data.
    Default: no

StatsTimeout NUMBER
    Timeout in seconds to timeout communication with the stats server.
    Default: 10

NOTES

All options expressing a size are limited to max 4GB. Values in excess will be resetted to the maximum.

FILES

@CFGDIR@/clamd.conf

AUTHORS

Tomasz Kojm <tkojm@clamav.net>, Kevin Lin <klin@sourcefire.com>

SEE ALSO

clamd(8), clamdscan(1), clamav-milter(8), freshclam(1), freshclam.conf(5)