Add mix tasks to detect spoofed posts and users

At least as far as we can
This commit is contained in:
Oneric 2024-03-17 20:07:16 -01:00
parent d441101200
commit 0648d9ebaa
2 changed files with 145 additions and 0 deletions

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@ -30,3 +30,27 @@ Attachments wil be scanned anyway in case local uploader was used in the past.
```sh
mix pleroma.security spoof-uploaded
```
### Search for counterfeit posts in database
Scans all notes in the database for signs of being spoofed.
!!! note
Spoofs targeting local accounts can be detected rather reliably
(with some restrictions documented in the tasks logs).
Counterfeit posts from remote users cannot. A best-effort attempt is made, but
a thorough attacker can avoid this and it may yield a small amount of false positives.
Should you find counterfeit posts of local users, let other admins know so they can delete the too.
=== "OTP"
```sh
./bin/pleroma_ctl security spoof-inserted
```
=== "From Source"
```sh
mix pleroma.security spoof-inserted
```

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@ -4,6 +4,7 @@
defmodule Mix.Tasks.Pleroma.Security do
use Mix.Task
import Ecto.Query
import Mix.Pleroma
alias Pleroma.Config
@ -49,6 +50,23 @@ defmodule Mix.Tasks.Pleroma.Security do
do_spoof_uploaded()
end
# Fuzzy search for potentially counterfeit activities in the database resulting from the same exploit
def run(["spoof-inserted"]) do
Logger.put_process_level(self(), :notice)
start_pleroma()
IO.puts("""
+----------------------+
| SPOOF SEARCH NOTES |
+----------------------+
Starting fuzzy search for counterfeit activities.
NOTE this can not guarantee detecting all counterfeits
and may yield a small percentage of false positives.
""")
do_spoof_inserted()
end
# +-----------------------------+
# | S P O O F - U P L O A D E D |
# +-----------------------------+
@ -162,6 +180,109 @@ defmodule Mix.Tasks.Pleroma.Security do
|> Enum.filter(fn {_, url} -> !(url in not_orphaned_urls) end)
end
# +-----------------------------+
# | S P O O F - I N S E R T E D |
# +-----------------------------+
defp do_spoof_inserted() do
IO.puts("""
Searching for local posts whose Create activity has no ActivityPub id...
This is a pretty good indicator, but only for spoofs of local actors
and only if the spoofing happened after around late 2021.
""")
idless_create =
search_local_notes_without_create_id()
|> Enum.sort()
IO.puts("Done.\n")
IO.puts("""
Now trying to weed out other poorly hidden spoofs.
This can't detect all and may have some false positives.
""")
likely_spoofed_posts_set = MapSet.new(idless_create)
sus_pattern_posts =
search_sus_notes_by_id_patterns()
|> Enum.filter(fn r -> !(r in likely_spoofed_posts_set) end)
IO.puts("Done.\n")
IO.puts("""
Finally, searching for spoofed, local user accounts.
(It's impossible to detect spoofed remote users)
""")
spoofed_users = search_bogus_local_users()
pretty_print_list_with_title(sus_pattern_posts, "Maybe Spoofed Posts")
pretty_print_list_with_title(idless_create, "Likely Spoofed Posts")
pretty_print_list_with_title(spoofed_users, "Spoofed local user accounts")
IO.puts("""
In total found:
#{length(spoofed_users)} bogus users
#{length(idless_create)} likely spoofed posts
#{length(sus_pattern_posts)} maybe spoofed posts
""")
end
defp search_local_notes_without_create_id() do
Pleroma.Object
|> where([o], fragment("?->>'id' LIKE ?", o.data, ^local_id_pattern()))
|> join(:inner, [o], a in Pleroma.Activity,
on: fragment("?->>'object' = ?->>'id'", a.data, o.data)
)
|> where([o, a], fragment("NOT (? \\? 'id') OR ?->>'id' IS NULL", a.data, a.data))
|> select([o, a], {a.id, fragment("?->>'id'", o.data)})
|> order_by([o, a], a.id)
|> Pleroma.Repo.all()
end
defp search_sus_notes_by_id_patterns() do
[ep1, ep2, ep3, ep4] = activity_ext_url_patterns()
Pleroma.Object
|> where(
[o],
# for local objects we know exactly how a genuine id looks like
# (though a thorough attacker can emulate this)
# for remote posts, use some best-effort patterns
fragment(
"""
(?->>'id' LIKE ? AND ?->>'id' NOT SIMILAR TO
? || 'objects/[a-f0-9]{8}-[a-f0-9]{4}-[a-f0-9]{4}-[a-f0-9]{4}-[a-f0-9]{12}')
""",
o.data,
^local_id_pattern(),
o.data,
^local_id_prefix()
) or
fragment("?->>'id' LIKE ?", o.data, "%/emoji/%") or
fragment("?->>'id' LIKE ?", o.data, "%/media/%") or
fragment("?->>'id' LIKE ?", o.data, "%/proxy/%") or
fragment("?->>'id' LIKE ?", o.data, ^ep1) or
fragment("?->>'id' LIKE ?", o.data, ^ep2) or
fragment("?->>'id' LIKE ?", o.data, ^ep3) or
fragment("?->>'id' LIKE ?", o.data, ^ep4)
)
|> join(:inner, [o], a in Pleroma.Activity,
on: fragment("?->>'object' = ?->>'id'", a.data, o.data)
)
|> select([o, a], {a.id, fragment("?->>'id'", o.data)})
|> order_by([o, a], a.id)
|> Pleroma.Repo.all()
end
defp search_bogus_local_users() do
Pleroma.User.Query.build(%{})
|> where([u], u.local == false and like(u.ap_id, ^local_id_pattern()))
|> order_by([u], u.ap_id)
|> select([u], u.ap_id)
|> Pleroma.Repo.all()
end
# +-----------------------------------+
# | module-specific utility functions |
# +-----------------------------------+