Discussion:
[Aide] Checksum Aide Alerts
Malcolm Dsouza
2017-05-03 18:56:44 UTC
Permalink
Hi,
We are presently using Aide for our Linux based Devices. As part of the
Aide alerts I observe that the checksum of certain files in /usr/lib,
/usr/bin and /lib show a Checksum alert as follows

*Changed files:*

f =... ..C: /usr/bin/myapp

f =... ..C: /usr/lib/libssl.so


However after in later aide reports (a week later or so) some of the above
alerts do not show up and the later aide reports show only


f =... ..C: /usr/bin/myapp

There are many instances of Checksum alerts (sha1) for various other
devices for different libraries and executables.

The root file system of the device cannot be accessed using login/remote
shell and hence I have come to conclude that this alert like a few other
ones shown for other devices are false positives.

We are using an ARM platform and a JFFS2 file system.

We have pre linking disabled and as I have read from many posts that pre
linking tends to result in false positives. Aide flags are set for
p+i+s+n+b+u+sha1

aide -v
Aide 0.15.1

Compiled with the following options:

WITH_MMAP
WITH_LSTAT64
WITH_READDIR64
WITH_ZLIB
WITH_GCRYPT
CONFIG_FILE = "/etc/aide.conf"


Could this be a problem in the GCRYPT library?

Could someone guide me as to how I can investigate the root cause of this
issue (what things can I try) and know for certain if this was indeed a
false positive?

Regards,
Max
Hannes von Haugwitz
2017-05-03 19:25:58 UTC
Permalink
Hi,
Post by Malcolm Dsouza
aide -v
Aide 0.15.1
Can you please try out the current stable version of AIDE (v0.16)?
Post by Malcolm Dsouza
Could this be a problem in the GCRYPT library?
Maybe... can you compile AIDE with libmhash and try if that makes a
difference?
Post by Malcolm Dsouza
Could someone guide me as to how I can investigate the root cause of this
issue (what things can I try) and know for certain if this was indeed a
false positive?
Please use verbose level 6 and provide the detailed changes for the
entries (files) in question (preferably with AIDE v0.16).

Additionally ensure that the AIDE database was not changed between the
AIDE runs (with AIDE 0.16 the checksums of the AIDE database(s) are
added to the end of the final report).

Best regards

Hannes

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