yara (1) Linux Manual Page

yara – find files matching patterns and rules written in a special-purpose language.

Synopsis

yara [OPTION]… RULES_FILE FILE | DIR | PID

Description

yara scans the given FILE, all files contained in directory DIR, or the process indentified by PID looking for matches of patterns and rules provided in a special purpose-language. The rules are read from RULES_FILE.

The options to yara(1) are:

-t tag –tag=tag

Print rules tagged as tag and ignore the rest. This option can be used multiple times.

-i identifier –identifier=identifier

Print rules named identifier and ignore the rest. This option can be used multiple times.

-n –negate

Print rules that doesn’t apply (negate)

-D –print-module-data

Print module data.

-g –print-tags

Print the tags associated to the rule.

-m –print-meta

Print metadata associated to the rule.

-s –print-strings

Print strings found in the file.

-p number –threads=number

Use the specified number of threads to scan a directory.

-l number –max-rules=number

Abort scanning after a number of rules matched.

-a seconds –timeout=seconds

Abort scanning after a number of seconds has elapsed.

-k slots –stack-size=slots

Set maximum stack size to the specified number of slots.

-d identifier=value

Define an external variable. This option can be used multiple times.

-x module=file

Pass file’s content as extra data to module. This option can be used multiple times.

-r –recursive

Scan files in directories recursively.

-f –fast-scan

Speeds up scanning by searching only for the first occurrence of each pattern.

-w –no-warnings

Disable warnings.

-v –version

Show version information.

Examples

$ yara /foo/bar/rules1 /foo/bar/rules2 .

Apply rules on /foo/bar/rules1 and /foo/bar/rules2 to all files on current directory. Subdirectories are not scanned.

$ yara -t Packer -t Compiler /foo/bar/rules bazfile

Apply rules on /foo/bar/rules to bazfile. Only reports rules tagged as Packer or Compiler.

$ cat /foo/bar/rules1 | yara -r /foo

Scan all files in the /foo directory and its subdirectories. Rules are read from standard input.

$ yara -d mybool=true -d myint=5 -d mystring="my string" /foo/bar/rules bazfile

Defines three external variables mybool myint and mystring.

$ yara -x cuckoo=cuckoo_json_report /foo/bar/rules bazfile

Apply rules on /foo/bar/rules to bazfile while passing the content of cuckoo_json_report to the cuckoo module.

Author

Victor M. Alvarez <plusvic [at] gmail.com>;<vmalvarez [at] virustotal.com>