Provided by: aide_0.18-2_amd64 
NAME
aide.conf - The configuration file for Advanced Intrusion Detection Environment
SYNOPSIS
aide.conf is the configuration file for Advanced Intrusion Detection Environment.
aide.conf contains the runtime configuration aide uses to initialize or check the AIDE
database.
FILE FORMAT
aide.conf is case-sensitive. Leading and trailing white spaces are ignored. Each config
lines must end with new line.
AIDE uses the backslash character (\) as escape character for ' ' (space), '@' and '\'
(backslash) (e.g. '\ ' or '\@'). To literally match a '\' in a file path with a regular
expression you have to escape the backslash twice (i.e. '\\\\').
There are three types of lines in aide.conf. First there are the configuration options
which are used to set configuration parameters and define groups. Second, there are
(restricted) rules that are used to indicate which files are added to the database. Third,
macro lines define or undefine variables within the config file. Lines beginning with #
are ignored as comments.
CONFIG OPTIONS
These lines have the format parameter=value. See URLS for a list of valid urls.
database_in (type: URL, default: see --version output, added in AIDE v0.17)
database (DEPRECATED since AIDE v0.17, will be removed in AIDE v0.19)
The url from which database is read. There can only be one of these lines. If there
are multiple database lines then the first is used.
Examples:
database_in=file:/var/lib/aide/aide.db
Read database locally from /var/lib/aide/aide.db.
database_in=stdin
Read database from stdin.
database_in=https://example.com/aide.db
Read database remotely from https://example.com/aide.db.
database_out (type: URL, default: see --version output)
The url to which the new database is written to. There can only be one of these
lines. If there are multiple database_out lines then the first is used.
database_new (type: URL, default: <none>)
The url from which the other database for --compare is read.
database_attrs (type: attribute expression, default: H, added in AIDE v0.16)
The attributes of the (uncompressed) database files which are to be added to the
reports in report level >= database_attributes . Only checksum attributes are
supported. To disable set database_attrs to 'E'.
database_add_metadata (type: bool, default: true, added in AIDE v0.16)
Whether to add the AIDE version and the time of database generation as comments to
the database file or not. This option may be set to false by default in a future
release.
log_level (type: log level, default: warning, added in AIDE v0.17)
The log level to use. Log messages are written to stderr. If there are multiple
log_level lines then the first one is used. The --log-level or -L command line
option overwrites this option.
The following log levels are available:
error: show unrecoverable issues that have to be handled by the user. Errors
are fatal to the AIDE process.
warning: additionally show recoverable issues that most likely lead to
unexpected behaviour and should be handled by the user
notice: additionally show recoverable issues that sometimes lead to
unexpected behaviour and might be handled by the user.
info: additionally show informational messages
rule: additionally show messages to help to debug the path rule matching
compare: additionally show messages to help to debug file comparison and
(special) attribute handling
config: additionally show messages to help to debug config and rule parsing
debug: additionally show messages that are useful to debug the application
(very verbose)
thread: additionally show messages about thread processing (e.g. broadcast
events)
trace: detailed information about the flow of the application (e.g. in-loop
logging) (even more verbose)
verbose (type: number, range: 0 - 255, default: 5, REMOVED in AIDE v0.17)
Removed, use log_level and report_level options instead.
gzip_dbout (type: bool, default: false)
Whether the output to the database is gzipped or not. This option is available only
if zlib support is compiled in.
root_prefix (type: path, default: <empty>, added in AIDE v0.16)
The prefix to strip from each file name in the file system before applying the
rules and writing to database. AIDE removes a trailing slash from the prefix. If
there are multiple root_prefix lines then the first one is used. This option has no
effect in compare mode.
acl_no_symlink_follow (type: bool, default: false)
Whether to check ACLs for symlinks or not. This option is available only if acl
support is compiled in.
warn_dead_symlinks (type: path, default: false)
Whether to warn about dead symlinks or not.
config_version (type: string, default: <empty>)
The value of config_version is printed in the report and also printed to the
database. This is for informational purposes only. It has no other functionality.
config_check_warn_unrestricted_rules (type: bool, default: false, added in AIDE v0.18)
Whether to warn on unrestricted rules during config check. To explicitly define
unrestricted rules use 0 (zero) as restriction character.
num_workers (type: number|percentage, default: 1, added in AIDE v0.18)
Specifies the number of simultaneous workers (threads) for file attribute
processing (i.a. hashsum calculation).
The number of workers can be a positive integer (e.g. '4') or the percentage of the
available processors (e.g. '60%'). The resulting number of workers is rounded up to
the next integer (e.g. '60%' of 8 processors results in 5 workers).
If there are multiple num_workers lines then the first one is used.
Use 0 (zero) to disable multi-threading.
The default value 1 (single worker thread) may be changed in a future release.
REPORT OPTIONS
report_url (type: URL, default: stdout)
The URL that the output is written to.
Multiple instances of the report_url option are supported.
Examples:
report_url=file:/var/log/aide.log
Write report to /var/log/aide.log.
report_url=stdout
Write report to stdout.
report_url=syslog:<LOG_FACILITY>
Write report to syslog using LOG_FACILITY.
The following report options are available (to take effect they have to be set before
report_url):
report_level (type: report level, default: changed_attributes, added in AIDE v0.17)
The report level to use. The available report levels are as follows:
minimal: print single line whether AIDE found differences to the database
summary: additionally print number of added, removed and changed files
database_attributes: additionally print database checksums
list_entries: additionally print lists of added, removed and changed entries
changed_attributes: additionally print details about changed entries
Example:
File: /var/lib/apt/extended_states
Perm : -rw-r--r-- | -rw-------
Uid : 0 | 106
The left column shows the old value (e.g. from the database_in database) and
the right column shows the new value (e.g. from the file system).
added_removed_attributes: additionally print details about added and removed
attributes
added_removed_entries: additionally print details about added and removed entries
report_format (type: report format, default: plain, added in AIDE v0.18)
The report format to use. The available report formats are as follows:
plain: Print report in plain human-readable format.
json: Print report in json machine-readable format.
report_base16 (type: bool, default: false, added in AIDE v0.17)
Base16 encode the checksums in the report. The default is to report checksums in
base64 encoding.
report_detailed_init (type: bool, default: false, added in AIDE v0.16)
Report added files (report level >= list_entries) and their details (report level
>= added_removed_entries) in initialization mode.
report_quiet (type: bool, default: false, added in AIDE v0.16)
Suppress report output if no differences to the database have been found.
report_append (type: bool, default: false, added in AIDE v0.17)
Append to the report URL.
report_grouped (type: bool, default: true, added in AIDE v0.17)
grouped (DEPRECATED since AIDE v0.17, will be removed in AIDE v0.19)
Group the files in the report by added, removed and changed files.
report_summarize_changes (type: bool, default: true, added in AIDE v0.17)
summarize_changes (DEPRECATED since AIDE v0.17, will be removed in AIDE v0.19)
Summarize changes in the added, removed and changed files sections of the report.
The general format is like the string YlZbpugamcinHAXSEC, where Y is replaced by
the file-type ('f' for a regular file, 'd' for a directory, 'l' for a symbolic
link, 'c' for a character device, 'b' for a block device, 'p' for a FIFO, 's' for a
unix socket, 'D' for a Solaris door, 'P' for a Solaris event port, '!' if file type
has changed and '?' otherwise).
The Z is replaced as follows: A '=' means that the size has not changed, a '<'
reports a shrinked size and a '>' reports a grown size. The other letters in the
string are the actual letters that will be output if the associated attribute for
the item has been changed or a '.' for no change.
Otherwise a '+' is shown if the attribute has been added, a '-' if it has been
removed, a ':' if the attribute is ignored (but not forced) or a ' ' if the
attribute has not been checked.
The exceptions to this are: (1) a newly created file replaces each letter with a
'+', and (2) a removed file replaces each letter with a '-'.
The attribute that is associated with each letter is as follows:
o A l means that the link name has changed.
o A b means that the block count has changed.
o A p means that the permissions have changed.
o An u means that the uid has changed.
o A g means that the gid has changed.
o An a means that the access time has changed.
o A m means that the modification time has changed.
o A c means that the change time has changed.
o An i means that the inode has changed.
o A n means that the link count has changed.
o A H means that one or more message digests have changed.
The following letters are only available when explicitly enabled using configure:
o A A means that the access control list has changed.
o A X means that the extended attributes have changed.
o A S means that the SELinux attributes have changed.
o A E means that the file attributes on a second extended file system have
changed.
o A C means that the file capabilities have changed.
report_ignore_added_attrs (type: attribute expression, default: empty, added in AIDE
v0.16)
Attributes whose addition is to be ignored in the report.
report_ignore_removed_attrs (type: attribute expression, default: empty, added in AIDE
v0.16)
Attributes whose removal is to be ignored in the report.
report_ignore_changed_attrs (type: attribute expression, default: empty, added in AIDE
v0.16)
ignore_list (REMOVED in AIDE v0.17)
Attributes whose change is to be ignored in the report.
report_force_attrs (type: attribute expression, default: empty, added in AIDE v0.16)
report_attributes (REMOVED in AIDE v0.17)
Attributes which are always printed in the report for changed files. If an
attribute is both ignored and forced the attribute is not considered for file
change but printed in the final report as long as the file has been otherwise
changed.
report_ignore_e2fsattrs (type: string, default: 0, added in AIDE v0.16)
List (no delimiter) of ext2 file attributes which are to be ignored in the report.
See chattr(1) for the available attributes. Use 0 (zero) to not ignore any
attribute. Ignored attributes are represented by a ':' in the report.
By default AIDE also reports changes of the read-only attributes mentioned in
chattr(1) (see example below how to ignore those changes).
Example:
Ignore changes of the read-only ext2 file attributes verify (V), inline data
(N), indexed directory (I) and encrypted (E):
report_ignore_e2fsattrs=VNIE
GROUPS
Groups are aggregations of attributes.
Group definitions have the format <group name> = <attribute expression>.
Group names are limited to alphanumeric characters (A-Za-z0-9).
See ATTRIBUTES for a description of all available attributes.
Default groups
R p+ftype+i+l+n+u+g+s+m+c+md5+X
L p+ftype+i+l+n+u+g+X
> Growing file p+ftype+l+u+g+i+n+s+growing+X
H all compiled in hashsums (added in AIDE v0.17)
X acl+selinux+xattrs+e2fsattrs+caps (if attributes are compiled in, added in AIDE
v0.16)
E Empty group
Use 'aide --version' to list the default compound groups.
RULES
AIDE supports three types of rules:
Regular rule:
<regex> <attribute expression>
Files and directories matching the regular expression are added to the database.
Negative rule:
!<regex>
Files and directories matching the regular expression are ignored and not added to
the database. The children of matching directories are also ignored.
Equals rule:
=<regex> <attribute expression>
Files and directories matching the regular expression are added to the database.
The children of directories are only added if the regular expression ends with a
"/". The children of sub-directories are not added at all.
Every regular expression has to start with an explicit "/". An implicit ^ is added in
front of each regular expression. In other words, the regular expressions are matched at
the first position against the complete path. Special characters can be escaped using
two-digit URL encoding (for example, %20 to represent a space).
AIDE uses a deepest-match algorithm to find the tree node to search, but a first-match
algorithm inside the node. (see also rule log level).
See EXAMPLES for examples.
More in-depth discussion of the selection algorithm can be found in the AIDE manual.
RESTRICTED RULES
Restricted rules are like normal rules but can be restricted to file types (added in AIDE
v0.16). The following file types are supported:
f restrict rule to regular files
d restrict rule to directories
l restrict rule to symbolic links
c restrict rule to character devices
b restrict rule to block devices
p restrict rule to FIFO files
s restrict rule to UNIX sockets
D restrict rule to Solaris doors
P restrict rule to Solaris event ports
0 empty restriction, i.e. don't restrict rule (added in AIDE v0.18)
Multiple restrictions can be given as a comma-separated list.
The syntax of restricted rules is as follows:
Restricted regular rule
<regex> <file types> <attribute expression>
Restricted negative rule
!<regex> <file types>
Restricted equals rule
=<regex> <file types> <attribute expression>
MACRO LINES
@@define VAR val
Define variable VAR to value val.
@@undef VAR
Undefine variable VAR.
@@if boolean_expression (added in AIDE v0.18)
@@else
@@endif
@@if begins an if statement. It must be terminated with an @@endif statement. The
lines between @@if and @@endif are used if the boolean_expression evaluates to
true. If there is an @@else statement then the part between @@if and @@else is
used if boolean_expression evaluates to true otherwise the part between @@else and
@@endif is used.
Available operators and functions in boolean expressions:
not boolean_expression
Evaluates to true if the boolean_expression is false, and false if the
boolean_expression is true.
defined VARIABLE
Evaluates to true if VARIABLE is defined.
hostname HOSTNAME
Evaluates to true if HOSTNAME equals the hostname of the machine that AIDE is
running on. hostname is the name of the host without the domainname (ie
'hostname', not 'hostname.example.com').
exists PATH
Evaluates to true if PATH exists.
@@ifdef VARIABLE (DEPRECATED since AIDE v0.18, will be removed in AIDE v0.20)
same as @@if defined VARIABLE
@@ifndef VARIABLE (DEPRECATED since AIDE v0.18, will be removed in AIDE v0.20)
same as @@if not defined VARIABLE
@@ifhost HOSTNAME (DEPRECATED since AIDE v0.18, will be removed in AIDE v0.20)
same as @@if hostname HOSTNAME
@@ifnhost HOSTNAME (DEPRECATED since AIDE v0.18, will be removed in AIDE v0.20)
same as @@if not hostname HOSTNAME
@@{VAR}
@@{VAR} is replaced with the value of the variable VAR. If variable VAR is not
defined an empty string is used.
Variables are supported in strings and in regular expressions of selection lines.
Pre-defined marco variables:
@@{HOSTNAME}: hostname of the current system
@@include FILE
Include FILE.
The content of the file is used as if it were inserted in this part of the config
file.
The maximum depth of nested includes is 16.
@@include DIRECTORY REGEX [RULE_PREFIX] (added in AIDE v0.17)
Include all (regular) files found in DIRECTORY matching regular expression REGEX
(sub-directories are ignored). The file are included in lexical sort order.
If RULE_PREFIX is set, all rules included by the statement are prefixed with given
RULE_PREFIX (added in AIDE v0.18). Prefixes from nested include statements are
concatenated.
The content of the files is used as if it were inserted in this part of the config
file.
@@x_include FILE (added in AIDE v0.17)
@@x_include DIRECTORY REGEX [RULE_PREFIX] (added in AIDE v0.17)
@x_include is identical to @@include, except that if a config file is executable is
is run and the output is used as config.
If the executable file exits with status greater than zero or writes to stderr aide
stops with an error.
For security reasons DIRECTORY and each executable config file must be owned by the
current user or root. They must not be group- or world-writable.
@@x_include_setenv VAR VALUE (added in AIDE v0.17)
Adds the variable VAR with the value VALUE to the environment used for config file
execution.
Environment variable names are limited to alphanumeric characters (A-Za-z0-9) and
the underscore '_' and must not begin with a digit.
TYPES
bool
Valid values are yes, true, no or false.
attribute expression
An attribute expression is of the following form:
<attribute/group>
| <expr> + <attribute/group>
| <expr> - <attribute/group>
URLS
Urls can be one of the following. Input urls cannot be used as outputs and vice versa.
stdout
stderr Output is sent to stdout, stderr respectively.
stdin Input is read from stdin.
file:/path
Input is read from path or output is written to path.
fd:number
Input is read from filedescriptor number or output is written to number.
syslog:LOG_FACILITY
Output is written to syslog using LOG_FACILITY.
ATTRIBUTES
File attributes
ftype file type (added in AIDE v0.15)
p permissions
i inode
l link name
n number of links
u user
g group
s size
b block count
m mtime
a atime
c ctime
acl access control list (requires libacl)
selinux
selinux attributes (requires libselinux)
xattrs extended attributes (requires libattr)
e2fsattrs
file attributes on a second extended file system, see also report_ignore_e2fsattrs
option (requires libext2fs, added in AIDE v0.15)
caps file capabilities (requires libcap2, added in AIDE v0.17)
Use 'aide --version' to show which compiled-in attributes are available.
Special attributes
S check for growing size (DEPRECATED since AIDE v0.18, will be removed in AIDE v0.20)
Use growing+s attributes instead
I ignore changed filename
When I is used, the inode of the old file is used to search for a moved file in the
new database.
Source and target file have to be located in the same directory and must share the
same attributes (except for special attributes ANF, ARF, I, growing, and
compressed).
For moved entries a change of the ctime attribute is ignored.
growing
ignore growing file (added in AIDE v0.18)
When growing is used, changes of the following attributes are ignored:
size: if new size is greater than old size
bcount: if new bcount is greater than old bcount
atime: if new atime is greater than old atime
mtime: if new mtime is greater than old mtime
ctime: if new ctime is greater than old ctime
hashsums: if the hashsum of the new file restricted to the old size equals the
hashsums of the old file
For hashsum attributes the growing attribute is ignored in compare mode.
compressed
ignore compressed file (added in AIDE v0.18)
When compressed is used, the uncompressed hashsums of the new compressed file
(supported compressions: gzip) are used to search for the uncompressed file in the
old database.
The old uncompressed and the new compressed file have to be located in the same
directory and must share the same attributes (except for special attributes ANF,
ARF, I, growing, and compressed) including at least one hashsum.
Changes of the inode, size, bcount and ctime attributes are ignored.
The growing attribute (i.e. the old file size) is not considered for compressed
files during the calculation of the uncompressed hashsums.
The compressed attribute is ignored in compare mode.
ANF allow new files
When 'ANF' is used, new files are added to the new database, but are ignored in the
report.
ARF allow removed files
When 'ARF' is used, files missing on disk are omitted from the new database, but
are ignored in the report.
Hashsums attributes
md5 MD5 checksum (not in libgcrypt FIPS mode)
sha1 SHA-1 checksum
sha256 SHA-256 checksum
sha512 SHA-512 checksum
rmd160 RIPEMD-160 checksum
tiger tiger checksum
haval haval256 checksum (libmhash only)
crc32 crc32 checksum
crc32b crc32 checksum (libmhash only)
gost GOST R 34.11-94 checksum
whirlpool
whirlpool checksum
stribog256
GOST R 34.11-2012, 256 bit checksum (libgcrypt only, added in AIDE v0.17)
stribog512
GOST R 34.11-2012, 512 bit checksum (libgcrypt only, added in AIDE v0.17)
Use 'aide --version' to show which hashsums are available.
EXAMPLES
/ R This adds all files on your machine to the database. This one line is a fully
qualified configuration file.
!/dev$ This ignores the /dev directory structure.
=/foo R
Only /foo and /foobar are taken into the database. None of their children are
added.
=/foo/ R
Only /foo and its children (e.g. /foo/file and /foo/directory) are taken into the
database. The children of sub-directories (e.g. /foo/directory/bar) are not added.
/ d,f R
Only add directories and files to the database
!/run d
/run R Add all but directory entries to the database
/run d R-m-c-i
/run R Use specific rule for directories
Suggested Groups
OwnerMode = p+u+g+ftype
Check permissions, owner, group and file type
Size = s+b
Check size and block count
InodeData = OwnerMode+n+i+Size+l+X
StaticFile = m+c+Checksums
Files that stay static
Full = InodeData+StaticFile
Full = ftype+p+l+u+g+s+m+c+a+i+b+n+H+X
/ 0 Full
This line defines group Full. It has all attributes, all compiled in hashsums (H)
and all compiled in extra file attributes (X). See '--version' output for the
compiled in hashsums and extra groups. The example rule is the typical catch-all
rule at the end of the rule list.
VarTime = InodeData+Checksums
/etc/ssl/certs/ca-certificates\\.crt$ VarTime
Files that change their mtimes or ctimes but not their contents.
VarInode = VarTime-i
/var/lib/nfs/etab$ f VarInode
Files that are recreated regularly but do not change their contents
VarFile = OwnerMode+n+l+X
/etc/resolv\\.conf$ f VarFile
Files that change their contents during system operation
VarDir = OwnerMode+n+i+X
/var/lib/snmp$ d VarDir
Directories that change their contents during system operation
RecreatedDir = OwnerMode+n+X
/run/samba$ d RecreatedDir
Directories that are recreated regularly and change their contents
Log Handling
Logs pose a number of special challenges to AIDE. An active log is nearly constantly
being written to. The process of log rotation changes file names for files that are
supposed to have unaltered contents. To save space, Logs are compressed in the process of
their rotation, and finally, they get deleted. AIDE is supposed to handle all those cases
without generating reports, and it is still expected to flag the cases when an attacker
tampers with logs.
The following examples suggest a way to handle the common case of log rotation with the
logrotate(8) program, with its options compress, delaycompress and nocopytruncate set.
The vast majority of logs are rotated this way on most Linux systems.
ActLog=Full+growing+ANF+I
/var/log/foo\\.log$ f ActLog
An Active Log is typically named foo.log. It is constanty being written to. The
file does neither change its mode nor its inode number. The size only increases,
and what is written to the file is not supposed to change (growing). During log
rotation, foo.log is typically renamed to foo.log.1 (or foo.log.0) and the process
is instructed to write to a new foo.log. Log content is written to a new file
(ANF) and will eventually be renamed to foo.log.1 (I). The growing attribute
suppresses reports for files that just had content appended when compared to the
database. A change of the old content is still reported!
RotLog=Full
/var/log/foo\\.log\\.1$ f RogLog
foo.log.0 or foo.log.1 is called the Rotated Log, the previously active log renamed
to the first name of the Log Series that is formed by the rotation mechanism.
Right after rotation, the file might still being written to by the daemon. To
aide, this looks like the Active Log's size decreases and its inode and timestamps
change. The Rotated Log is not supposed to change its attributes once the process
has stopped writing to it. Reports might be generated if aide runs while the
process still writes to the Rotated Log, but this is quite unlikely to happen.
Some log rotation mechanisms rename foo.log to foo.log.0 to foo.log.1.gz, others
rename foo.log to foo.log.1 to foo.2.log.gz.
CompSerLog=Full+I+compressed
/var/log/foo\\.log\\.2\\.gz$ f CompSerLog
In the next rotation step, foo.log.1 gets compressed to foo.log.2.gz, becoming the
Compressed Log in the Log Series. With this rule, AIDE does not report this step
because it uncompresses the contents of the file and takes the checksum of the
uncompressed content. The contents strictly doesn't change, but some attribute
changes are ignored (compressed).
MidlSerLog=Full+I
/var/log/foo\\.log\\.[345]\\.gz$ f MidlSerLog
In the next log rotation, all foo.log.{x} get renamed to foo.log.{x+1}. The other
attributes are not supposed to change.
LastSerLog=Full+ARF
/var/log/foo\\.log\\.6\\.gz$ f LastSerLog
The configuration of the log rotation process specifies a number of log generations
to keep. The last log in the series is therefore removed from the disk (ARF).
aide 0.18 does not yet support the following cases of log rotation:
empty files
It might be the case that a log is actually created, but never written to. This
commonly happens on rarely used web servers that use the log rotation as a method
to cater for data protection regulation. In result, all files in a series are
identical, breaking the heuristics that aide uses to detect log rotation. A
possible workaround is to begin a newly rotated log with a timestamp. With
logrotate, this can be done in a postrotate scriptlet.
nodelaycompress
With logrotate's nodelaycompress option, a log is immediately compressed after
renaming it from the Active Log name. For the time being, it is recommended to
always use the delaycompress option to avoid this behavior.
copytruncate
With logrotate's copytruncate option, the Active Log is not renamed and newly
created but copied to the new file name. After the copy operation, the old file is
truncated to zero size, allowing the daemon to continuously write to the already
open file handle. aide uses the Inode number to detect the rotation process. That
doesn't work with copytruncate because the Inode stays with the Active Log. For
the time being, it is recommended to avoid the copytruncate option to avoid this
behavior.
HINTS
In the following, the first is not allowed in AIDE. Use the latter instead.
/foo epug
/foo e+p+u+g
SEE ALSO
aide(1)
DISCLAIMER
All trademarks are the property of their respective owners. No animals were harmed while
making this webpage or this piece of software.