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clamd.conf(5) Clam AntiVirus 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 argu- ments 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 configu- ration 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 dae- mon 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 Write the daemon's pid to the 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 FailIfCvdOlderThan NUMBER Return with a nonzero error code if the virus database is older than the specified number of days. Default: -1 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: 100M 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 con- necting. The default is set to 30 to avoid timeouts with TCP sock- ets when processing large messages. If using a Unix socket, the value can be changed to 5. Note: the timeout for subsequents com- mands, and/or data chunks is specified by ReadTimeout. Default: 30 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: Max- Threads*MaxRecursion + MaxQueue - MaxThreads + 6 < RLIMIT_NOFILE. RLIMIT_NOFILE is the maximum number of open file descriptors (usu- ally 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 ConcurrentDatabaseReload BOOL Enable non-blocking (multi-threaded/concurrent) database reloads. This feature will temporarily load a second scanning engine while scanning continues using the first engine. Once loaded, the new en- gine takes over. The old engine is removed as soon as all scans us- ing the old engine have completed. This feature requires more RAM, so this option is provided in case users are willing to block scans during reload in exchange for lower RAM requirements. Default: yes VirusEvent COMMAND Execute a command when virus is found. Use the following environ- ment variables to identify the file and virus names: - $CLAM_VIRU- SEVENT_FILENAME - $CLAM_VIRUSEVENT_VIRUSNAME In the command string, '%v' will also be replaced with the virus name. Note: The '%f' filename format character has been disabled and will no longer be replaced with the file name, due to command injection security con- cerns. Use the 'CLAM_VIRUSEVENT_FILENAME' environment variable in- stead. For the same reason, you should NOT use the environment variables in the command directly, but should use it carefully from your executed script. 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 GenerateMetadataJson BOOL Record metadata about the file being scanned. Scan metadata is use- ful for file analysis purposes and for debugging scan behavior. The JSON metadata will be printed after the scan is complete if Debug is enabled. A metadata.json file will be written to the scan temp di- rectory if LeaveTemporaryFiles is enabled. Default: no User STRING Run the daemon as a specified user (the process must be started by root). Default: disabled Bytecode BOOL With this option enabled ClamAV will load bytecode from the data- base. It is highly recommended you keep this option turned on, oth- erwise 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: 10000 BytecodeUnsigned BOOL Allow loading bytecode from outside digitally signed .c[lv]d files. **Caution**: You should NEVER run bytecode signatures from untrusted sources. Doing so may result in arbitrary code execution. Default: no BytecodeMode STRING Set bytecode execution mode. Possible values: Auto - automatically choose JIT if possible, fallback to inter- preter 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 https://docs.clamav.net/faq/faq-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 https://docs.clamav.net/faq/faq-pua.html for the complete list of PUA categories. Default: disabled HeuristicAlerts BOOL In some cases (eg. complex malware, exploits in graphic files, and others), ClamAV uses special algorithms to provide accurate detec- tion. This option controls the algorithmic detection. Default: yes HeuristicScanPrecedence BOOL Allow heuristic match to take precedence. When enabled, if a heuris- tic 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 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 executa- bles. 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 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 peri- odically 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 Enable email signature-based phishing detection. Default: yes PhishingScanURLs BOOL Enable URL signature-based phishing detection (Heuristics.Phish- ing.Email.*) Default: yes 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 StructuredCCOnly BOOL With this option enabled the DLP module will search for valid Credit Card0umbers only. Debit and Private Label cards will not be searched. Default: No 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 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 ScanXMLDOCS BOOL This option enables scanning xml-based document files supported by libclamav. If you turn off this option, the original files will still be scanned, but without additional processing. Default: yes ScanHWP3 BOOL This option enables scanning HWP3 files. If you turn off this option, the original files will still be scanned, but without additional processing. Default: yes ScanOneNote BOOL This option enables scanning OneNote files. If you turn off this option, the original files will still be scanned, but without 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 ScanImage BOOL This option enables scanning of image (graphics). If you turn off this option, the original files will still be scanned, but without unpacking and additional processing. Default: yes ScanImageFuzzyHash BOOL This option enables detection by calculating a fuzzy hash of image (graphics) files. Signatures using image fuzzy hashes typically match files and documents by identifying images embedded or attached to those files. If you turn off this option, then some files may no longer be de- tected. Default: yes AlertBrokenExecutables BOOL Alert on broken executable files (PE & ELF). Default: no AlertBrokenMedia BOOL Alert on broken graphics files (JPEG, TIFF, PNG, GIF). Default: no AlertEncrypted BOOL Alert on encrypted archives and documents (encrypted .zip, .7zip, .rar, .pdf). Default: no AlertEncryptedArchive BOOL Alert on encrypted archives (encrypted .zip, .7zip, .rar). Default: no AlertEncryptedDoc BOOL Alert on encrypted documents (encrypted .pdf). Default: no AlertOLE2Macros BOOL Alert on OLE2 files containing VBA macros (Heuristics.OLE2.Contains- Macros). Default: no AlertExceedsMax BOOL When AlertExceedsMax is set, files exceeding the MaxFileSize, MaxS- canSize, or MaxRecursion limit will be flagged with the virus name starting with "Heuristics.Limits.Exceeded". Default: no AlertPhishingSSLMismatch BOOL Alert on emails containing SSL mismatches in URLs (might lead to false positives!). Default: no AlertPhishingCloak BOOL Alert on emails containing cloaked URLs (might lead to some false positives). Default: no AlertPartitionIntersection BOOL Alert on raw DMG image files containing partition intersections. Default: no DisableCache This option allows you to disable the caching feature of the engine. By default, the engine will store an MD5 in a cache of any files that are not flagged as virus or that hit limits checks. Warning: Disabling the cache will have a negative performance impact on large scans. Default: no CacheSize This option allows you to set the number of entries the cache can store. The value should be a square number or will be rounded up to the nearest square number. Default: 65536 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 MaxScanTime SIZE This option sets the maximum amount of time a scan may take to com- plete. The value is in milliseconds. The value of 0 disables the limit. WARNING: disabling this limit or setting it too high may re- sult allow scanning of certain files to lock up the scanning process/threads resulting in a Denial of Service. Default: 120000 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: 400M 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. Technical design limitations prevent ClamAV from scanning files greater than 2 GB at this time. Default: 100M MaxRecursion NUMBER Nested archives are scanned recursively, e.g. if a Zip archive con- tains a RAR file, all files within it will also be scanned. This op- tions specifies how deeply the process should be continued. Warning: setting this limit too high may result in severe damage to the sys- tem. Default: 17 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: 40M 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: 40M 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: 8M 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: 20M 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 im- age 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 MaxRecHWP3 NUMBER This option sets the maximum recursive calls to HWP3 parsing func- tion. HWP3 files using more than this limit will be terminated and alert the user. Scans will be unable to scan any HWP3 attachments if the recursive limit is reached. Negative values are not allowed. WARNING: setting this limit too high may result in severe damage or impact performance. Default: 16 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 perfor- mance. Default: 10000 PCRERecMatchLimit NUMBER This option sets the maximum recursive calls to the PCRE match func- tion 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 documen- tation. Negative values are not allowed and values > PCREMatchLimit are su- perfluous. WARNING: setting this limit too high may severely impact perfor- mance. Default: 2000 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 un- less 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: 100M OnAccessIncludePath STRING This option specifies a directory (including all files and directo- ries 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 OnAccessExcludeRootUID BOOL With this option you can exclude the root UID (0). Processes run un- der root will be able to access all files without triggering scans or permission denied events. Note that if clamd cannot check the uid of the process that gener- ated an on-access scan event (e.g., because OnAccessPrevention was not enabled, and the process already exited), clamd will perform a scan. Thus, setting OnAccessExcludeRootUID is not guaranteed to prevent every access by the root user from triggering a scan (unless OnAccessPrevention is enabled). Default: no OnAccessExcludeUID NUMBER With this option you can exclude specific UIDs. Processes with these UIDs will be able to access all files without triggering scans or permission denied events. This option can be used multiple times (one per line). Note: using a value of 0 on any line will disable this option en- tirely. To exclude the root UID (0) please enable the OnAccessEx- cludeRootUID option. Also note that if clamd cannot check the uid of the process that generated an on-access scan event (e.g., because OnAccessPrevention was not enabled, and the process already exited), clamd will perform a scan. Thus, setting OnAccessExcludeUID is not guaranteed to pre- vent every access by the specified uid from triggering a scan (un- less OnAccessPrevention is enabled). Default: disabled OnAccessExcludeUname STRING This option allows exclusions via user names when using the on-ac- cess scanning client. It can be used multiple times, and has the same potential race condition limitations of the OnAccessExcludeUID option. Default: disabled OnAccessMaxFileSize SIZE Files larger than this value will not be scanned in on access. Default: 5M OnAccessMaxThreads NUMBER Max number of scanning threads to allocate to the OnAccess thread pool at startup. These threads are the ones responsible for creating a connection with the daemon and kicking off scanning after an event has been processed. To prevent clamonacc from consuming all clamd's resources keep this lower than clamd's max threads. Default: 5 OnAccessCurlTimeout NUMBER Max amount of time (in milliseconds) that the OnAccess client should spend for every connect, send, and receive attempt when communicat- ing with clamd via curl. Default: 5000 (5 seconds) OnAccessMountPath STRING Specifies a mount point (including all files and directories under it), which should be scanned on access. This option can be used mul- tiple 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 OnAccessRetryAttempts NUMBER Number of times the OnAccess client will retry a failed scan due to connection problems (or other issues). Default: 0 OnAccessDenyOnError BOOL When using prevention, if this option is turned on, any errors that occur during scanning will result in the event attempt being de- nied. This could potentially lead to unwanted system behaviour with certain configurations, so the client defaults this to off and prefers allowing access events in case of scan or connection error. Default: no OnAccessExtraScanning BOOL Toggles extra scanning and notifications when a file or directory is created or moved. Requires the DDD system to kick-off extra scans. Default: no DisableCertCheck BOOL Disable authenticode certificate chain verification in PE files. Default: no NOTES All options expressing a size are limited to max 4GB. Values in excess will be reset to the maximum. FILES /usr/local/etc/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) ClamAV 1.4.4 December 4, 2013 clamd.conf(5)
NAME | DESCRIPTION | FILE FORMAT | DIRECTIVES | NOTES | FILES | AUTHORS | SEE ALSO
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