1. The Quarantine Room Mac Os Pro
2. The Quarantine Room Mac Os 13

I recently drew attention to the fact that, without a quarantine flag set on a download, it’s all too easy for malware to gain entry to a Mac, particularly if it’s running Mojave or earlier. This article looks in more detail at how setting the quarantine flag is controlled by apps and macOS, and explains how Apple mitigates this issue.

Apr 15, 2020 Prepare for your Mac to be out-of-action for at least a day while you do it. Follow these steps to erase your Mac and reinstall macOS: Create a new backup of your Mac using Time Machine. Hold Command+R while your Mac powers on to boot into Recovery Mode. From the macOS Utilities window, open Disk Utility. Xattr -p com.apple.quarantine /Users/user/dnscrypt-osxclient-1.0.12.dmg quarantine.attr xattr -w com.apple.quarantine '`cat quarantine.attr`' test.command This will apply the data gathered from the.dmg to the.command file - including download date and download app of the original dmg file.

Although apps and other software can set and remove quarantine flags using explicit code, this is most usually left to a setting in the Info.plist property list which every app is required to contain. The entry there which controls flag behaviour is named LSFileQuarantineEnabled, and you can inspect this in each app to check what should happen when that app creates a new file, for example when downloading something from the Internet. When this is set to true, every new file created by that app should have the quarantine flag set; when false, they won’t unless macOS overrides that behaviour. If an unsandboxed app’s Info.plist doesn’t set LSFileQuarantineEnabled explicitly, then the default is not to set the quarantine flag.

You can of course edit an app’s Info.plist, but in doing so will break its signature. You may be able to get away with this for the time being, particularly on older versions of macOS, but it generally isn’t a wise choice.

macOS also provides a set of overrides to what appears in the Info.plist of many apps. These are listed in the Additions item in /System/Library/CoreServices/CoreTypes.bundle/Contents/Resources/Exceptions.plist.

The Exceptions.plist property list contains five dictionaries:

• Additions, which assigns a lot of app categories, sets Java version requirements, and determines default settings for quarantine on documents created by apps.
• AppNapOverrides, which sets App Nap behaviours.
• HighResolutionOverrides, which overrides High Res options for apps.
• LaunchOverrides, which can disable specific version ranges of apps from being launched; these prevent many older apps from being run.
• MergeDocumentTypes, which merges some document types such as doc and docx for specific apps.
• Overrides, which can override other settings.

For example, the entry in the Additions dictionary for the popular BitTorrent client Transmission reads:
<key>org.m0k.transmission</key>
<dict>
<key>LSApplicationCategoryType</key>
<string>public-category.internet</string>
<key>LSFileQuarantineEnabled</key>
<true/>
</dict>

Referring to the app by its ID of org.m0k.transmission, that first assigns the app to an app category of public-category.internet, and then sets the app to set the quarantine flag on all documents that it creates, including everything that it downloads.

Among the existing overrides in Catalina, for example, are org.pythonmac.unspecified.BitTorrent and org.xlife.Xtorrent, which ensures that Transmission, Xtorrent and PythonMac BitTorrent clients should write quarantine flags to all their downloaded files. Although this Exceptions property list doesn’t cover every client, it should ensure that most do protect their downloads with quarantine flags.

There are two snags to this otherwise protective system: first, the file containing these overrides is protected, in Catalina being on the System volume, so the user is effectively prevented from changing it. Unlike app preferences, which can be managed by the user at the command line, there’s no way for the user to add their own overrides. If you download items using an app which doesn’t itself require the quarantine flag to be set, and Apple doesn’t provide an override for it to do so, there doesn’t appear to be any good way to add that yourself.

It’s also unclear whether this system works with command tools, which are single file executables. They can have their Info.plist embedded in the executable, but this is rare unless they need to be notarized. For many users, it might be helpful, for example, if the standard tool curl were to set quarantine flags, as it’s often used to bypass quarantine and thus presents a significant vulnerability.

Finally, for some users at least, an app setting the quarantine flag isn’t of much use, as that user routinely strips the flag from downloads. If you do that, you’re steering into as much as danger as you would using an app which never sets them in the first place.

I’m enormously grateful to @rosyna who pointed me in the right direction, again.

Display and manipulate extended attributes

Display, modify or remove the extended attributes of files, directories or symbolic links.
These are indicated by ls with an @, for example:Extended attributes are arbitrary metadata stored separately from the basic filesystem attributes (such as modification time or file size).

value is often a null-terminated UTF-8 string, but can be arbitrary binary data.

The Quarantine Room Mac Os Pro

Exit status

HOWEVER, no message is displayed and then return code is 0 if the file does not exist!

For system call errors, both the error code and error string are output

No such file: file with a return status of 1 is reported for symbolic links if -s is not supplied!

[Errno 32] Broken pipe might be reported if xattr is piped to head

The Quarantine Room Mac Os 13

Some attribute data may have a fixed length that is enforced by the system. For example,

Warning:

• Some extended attribute values can be VERY large (like 3,649,818 bytes producing a hex&char display of several megabytes).
• Displaying this to a terminal may not be a good idea.

EXAMPLES

000 CD B4 BF D6 65 3E 83 91 82 4E 6B D3 00 1E 6B 60  ....e>...Nk...k` 010 B4 26 CE 16  .&.. 014