Donncha Ó Cearbhaill
c95e6659c6
Several MVT commands have nothing to do with the acquisition of one platform, yet they were reachable only through mvt-ios and mvt-android. Asking which version is installed or downloading the public indicators meant picking one of the two platform commands arbitrarily, and each of those tasks had to be written, documented and maintained twice. Add a third console script, mvt, hosting the commands which belong to no platform: version and download-iocs for now, with completion following in a later commit. Commands installed in the new mvt.cli_plugins entry-point group are registered on mvt, and on mvt only, so that a command package chooses the CLI each of its commands is added to: mvt.ios.cli_plugins for mvt-ios, mvt.android.cli_plugins for mvt-android and mvt.cli_plugins for mvt. A command wanted on both platform CLIs is registered in both platform groups; no group adds a command to every CLI. The MVT_CUSTOM_COMMANDS variable loads command files and folders into mvt the way the platform variables already do for mvt-ios and mvt-android. Run on its own, mvt prints the banner and its help instead of a usage error. The help text reminds that the forensic analysis of an acquisition runs through mvt-ios and mvt-android, so that the command which knows nothing about acquisitions says where they are analysed. version and download-iocs stay on mvt-ios and mvt-android for now, so that no documented invocation stops working. They are to be dropped from the platform CLIs in a later release, once mvt has been available long enough for the change to be announced. Unlike mvt-ios and mvt-android, which point at their subpackages, the console script points at mvt.cli:main and the mvt package re-exports nothing of it. Importing mvt has to stay cheap and free of side effects: it is the package plugins import from, and pulling in Click, the CLI and everything the commands import merely because something imported mvt would work against that. While here, give the version command of both platform CLIs the context settings every other command already has, so that "mvt-ios version -h" prints its help instead of failing on an unknown option.
4.5 KiB
Indicators of Compromise (IOCs)
MVT uses Structured Threat Information Expression (STIX) files to identify potential traces of compromise.
These indicators of compromise are contained in a file with a particular structure of JSON with the .stix2 or .json extensions.
You can indicate a path to a STIX2 indicators file when checking iPhone backups or filesystem dumps. For example:
mvt-ios check-backup --iocs ~/ios/malware.stix2 --output /path/to/iphone/output /path/to/backup
Or, with data from an Android backup:
mvt-android check-backup --iocs ~/iocs/malware.stix2 /path/to/android/backup/
After extracting forensics data from a device, you are also able to compare it with any STIX2 file you indicate:
mvt-ios check-iocs --iocs ~/iocs/malware.stix2 /path/to/iphone/output/
The --iocs option can be invoked multiple times to let MVT import multiple STIX2 files at once. For example:
mvt-ios check-backup --iocs ~/iocs/malware1.stix --iocs ~/iocs/malware2.stix2 /path/to/backup
It is also possible to load STIX2 files automatically from the environment variable MVT_STIX2:
export MVT_STIX2="/home/user/IOC1.stix2:/home/user/IOC2.stix2"
Network Access
When checking URL indicators, MVT follows recognized shortened URLs with an
HTTP HEAD request. URL checks are deduplicated and run concurrently, with at
most 20 requests in progress at a time. Redirects within an individual URL
chain are still followed sequentially. The following environment variables
control these requests:
MVT_NETWORK_ACCESS_ALLOWEDenables or disables network requests. It defaults totrue. Set it tofalseto prevent MVT from attempting to resolve shortened URLs.MVT_NETWORK_TIMEOUTsets the request timeout in seconds. It defaults to15.
For example, to run IOC checks without resolving shortened URLs:
MVT_NETWORK_ACCESS_ALLOWED=false mvt-ios check-iocs \
--iocs ~/iocs/malware.stix2 /path/to/iphone/output/
STIX2 Support
So far MVT implements only a subset of STIX2 specifications:
- It only supports checks for one value (such as
[domain-name:value='DOMAIN']) and not boolean expressions over multiple comparisons - It only supports the following types:
domain-name:value,process:name,email-addr:value,file:name,file:path,file:hashes.md5,file:hashes.sha1,file:hashes.sha256,app:id,configuration-profile:id,android-property:name,url:value(but each type will only be checked by a module if it is relevant to the type of data obtained)
Known repositories of STIX2 IOCs
- The Amnesty International investigations repository contains STIX-formatted IOCs for:
- This repository contains IOCs for Android stalkerware including a STIX MVT-compatible file.
- We are also maintaining a list of IOCs in STIX format from public spyware campaigns.
You can automatically download the latest public indicator files with the command mvt download-iocs. The per-platform forms mvt-ios download-iocs and mvt-android download-iocs do the same thing. These commands download the list of indicators from the mvt-indicators repository and store them in the appdir folder. They are then loaded automatically by MVT.
Please open an issue to suggest new sources of STIX-formatted IOCs.