SightingDB is a database designed for Sightings, a technique to count items. This is helpful for Threat Intelligence as Sightings allow to enrich indicators or attributes with Observations, rather than Reputation.

Simply speaking, by pushing data to SightingDB, you will get the first time it was observed, the last time, its count.

However, it will also provide the following features:

• Keep track of how many times something was searched
• Keep track of the hourly statistics per item
• Get the consensus for each item (how many namespaces contain the same value)
• Expire data with a per-value TTL
• Answer lookups over DNS, using the DNSBL conventions security tooling already speaks
• Ingest from a MISP ZeroMQ feed, and import STIX 2.1 bundles
• Browse namespaces and values in a browser, with a histogram of when each value was seen

SightingDB is designed to scale writing and reading. There is no global lock: namespaces are locked independently, and within a namespace each value has its own lock, so concurrent writes to different values never contend.

The database is held in memory and snapshotted to disk (see dbdir below). Set no dbdir to run purely in memory.

Building

1. Make sure you have Rust and Cargo installed. The toolchain is pinned in rust-toolchain.toml; rustup will fetch it automatically.
2. Run make (or cargo build).

You will need OpenSSL development headers to build (libssl-dev on Debian/Ubuntu, openssl from Homebrew on macOS).

Running

To run from the source directory:

1. Generate a certificate: ./target/debug/sightingdb -c etc/sightingdb.toml --install-selfsigned-keys
2. Start the daemon: ./target/debug/sightingdb -c etc/sightingdb.toml

--install-selfsigned-keys writes a self-signed certificate and a 0600 key at the configured ssl_cert and ssl_key paths and exits. It never overwrites an existing file, so pointing those settings at a real certificate is safe. The generated certificate names localhost, 127.0.0.1 and ::1, lasts a year, and is for getting started — clients have to skip verification (curl -k).

Set ssl = false in [daemon] to serve plain HTTP instead.

Without -c, the configuration is looked up in /etc/sightingdb/sightingdb.toml and then ~/.sightingdb/sightingdb.toml.

Running as a service

The recommended way to run SightingDB in the background is under a service manager, which handles restarts, log capture and startup ordering for you. A hardened systemd unit is provided:

sudo install -m 0644 etc/sightingdb.service /etc/systemd/system/
sudo systemctl daemon-reload
sudo systemctl enable --now sightingdb

Keep daemonize = false for that, and point log4rs at a console appender so the logs land in the journal (journalctl -u sightingdb).

Setting daemonize = true instead makes SightingDB detach on its own: it re-executes itself with stdin on /dev/null, stdout and stderr on the log_out and log_err files, and its own process group, then the launcher exits. A pid file is written to the first writable location out of /var/run/sightingdb.pid, ~/.sightingdb/sightingdb.pid or ./sightingdb.pid, and removed again on a clean shutdown.

Detaching by re-executing rather than by forking is deliberate. fork carries over only the calling thread, so a forked daemon silently loses anything already running in the background — including log4rs' own configuration reloader. The child here starts from a clean exec, so refresh_rate keeps working. Nothing changes directory either, so relative paths in the configuration keep resolving.

Send SIGTERM to stop: in-flight requests are drained, the database is written out, and the pid file is removed.

Options

-c, --config <FILE>          Configuration file (default: see above)
    --install-selfsigned-keys Write a self-signed cert and key, then exit
    --import-stix <PATH>     Import STIX 2.1 bundles, then exit
-l, --logging-config <FILE>  log4rs configuration file (default: etc/log4rs.yml)
-k, --apikey <APIKEY>        Set the default API key, replacing the built-in 'changeme'
-v, --verbose...             Increase verbosity

Client Demo

Writing

$ curl -k https://localhost:9999/w/my/namespace/?val=127.0.0.1
{"message":"ok","count":1}
$ curl -k https://localhost:9999/w/another/namespace/?val=127.0.0.1
{"message":"ok","count":1}
$ curl -k https://localhost:9999/w/another/namespace/?val=127.0.0.1
{"message":"ok","count":2}

Pass timestamp=<unix seconds> to record a sighting at a specific time; without it the sighting is recorded now.

Pass ttl=<seconds> to expire the value that long after it was last seen. Writing the value again pushes the deadline out; writing without ttl= leaves the existing one alone, and ttl=0 clears it. Expired values read as 404 immediately and are reclaimed by the next sweep, which also gives back the consensus they were holding.

Reading

$ curl -k https://localhost:9999/r/my/namespace/?val=127.0.0.1
{"value":"127.0.0.1","first_seen":1566624658,"last_seen":1566624658,"count":1,"tags":"","ttl":0,"consensus":2}

$ curl -k https://localhost:9999/r/another/namespace/?val=127.0.0.1
{"value":"127.0.0.1","first_seen":1566624686,"last_seen":1566624689,"count":2,"tags":"","ttl":0,"consensus":2}

$ curl -k https://localhost:9999/rs/my/namespace/?val=127.0.0.1
{"value":"127.0.0.1","first_seen":1593719022,"last_seen":1593721509,"count":10,"tags":"","ttl":0,"consensus":1,"stats":{"1593716400":2,"1593720000":8}}

Omit val= to list every value in a namespace:

$ curl -k https://localhost:9999/r/my/namespace/
{"attributes":[{"value":"127.0.0.1","first_seen":1566624658,"last_seen":1566624658,"count":1,"tags":"","ttl":0,"consensus":2}]}

Reading is recorded as a "shadow sighting" under _shadow/<namespace>, so you can see how often a value was searched for. Add noshadow to the query string to suppress that.

Bulk

$ curl -k -X POST https://localhost:9999/wb -H 'Content-Type: application/json' \
    -d '{"items":[{"namespace":"my/namespace","value":"127.0.0.1"}]}'
{"message":"ok","written":1}

timestamp, ttl and noshadow are optional on each item.

Authentication

$ curl -H 'Authorization: changeme' -k https://localhost:9999/w/my/namespace/?val=127.0.0.1
{"message":"ok","count":1}

Authentication is on unless authenticate=false is set in the configuration. Keys and their permissions are declared in the [acl] section; see below.

REST Endpoints

/w: write (GET)
/wb: write in bulk mode (POST)
/r: read (GET)
/rs: read with statistics (GET)
/rb: read in bulk mode (POST)
/rbs: read with statistics in bulk mode (POST)
/d: delete (GET)
/c: configure (GET, not implemented)
/i: info (GET)

Status codes

Every endpoint answers with JSON and a meaningful status code:

200 OK         the request succeeded
400 Bad Request malformed query string, JSON body, or a missing val=
401 Unauthorized no Authorization header was sent
403 Forbidden   unknown API key, or an attempt to reach the _config tree
404 Not Found   no such namespace, or no such value inside it
501 Not Implemented  /c

Configuration

Either listener can be turned off, so one instance can serve HTTP, DNS, or both. enabled = false under [daemon] runs DNS only; enabled = false under [dns] (or simply omitting the section) runs HTTP only. Disabling both is a startup error rather than a process that listens on nothing.

Beyond the listen address and TLS settings, [daemon] accepts:

enabled           Serve the HTTP API (default true).

dbdir             Directory for snapshots. Unset or blank runs in memory only.
snapshot_interval Seconds between snapshots (default 300). 0 saves only on shutdown.
sweep_interval    Seconds between eviction sweeps (default 60). 0 disables the sweeper.
stats_retention   Hourly statistics buckets kept per value (default 0 = unlimited).
shadow_ttl        Seconds a shadow sighting is kept (default 0 = forever).

The retention settings default to keeping everything, so upgrading an existing install never starts discarding data on its own. The configuration shipped in etc/sightingdb.toml sets 30-day windows for both, which is what bounds memory growth — without them, statistics accumulate one bucket per hour per value and _shadow/* grows for every distinct search, forever.

DNS lookups

SightingDB can answer over DNS as well as HTTP, following the DNSBL/RBL conventions, so anything that can already consult a blocklist — Postfix, rspamd, Suricata, a shell script with dig — can query it unmodified.

$ dig +short 4.3.2.1.malware.sdb.example.com
127.0.0.1

$ dig +short 9.9.9.9.malware.sdb.example.com
127.0.0.3

$ dig +short TXT 9.9.9.9.malware.sdb.example.com
"count=15 first_seen=1786774648 last_seen=1786774648 consensus=1 ttl=86400 tags=\"\""

The TXT record carries every field the HTTP API reports. tags is quoted because it is free-form, and a record too long for one DNS character-string is split across several, which clients join back together.

A value that was never seen answers NXDOMAIN, which is both the DNSBL idiom and what lets resolvers cache the negative. A value that was seen answers with a 127.0.0.x address whose last octet gives the order of magnitude: 1 is once, 2 is single digits, 3 is tens, and so on up to 9. A client that only checks "did I get an address at all" works unchanged.

Three ways of spelling a value in the query name are supported, chosen per namespace in the configuration:

ip      4.3.2.1.malware.sdb.example.com    ->  1.2.3.4
        (reversed octets, as RBLs do; IPv6 uses the ip6.arpa nibble form)
domain  evil.com.domains.sdb.example.com   ->  evil.com
base32  <base32 of the value>.hashes.sdb.example.com

TCP is supported, and a reply too large for a datagram comes back truncated so the client retries over it.

Before you enable it

DNS has no authentication. The [acl] section does not apply, so anything reachable over DNS is readable by anyone who can send a packet. Accordingly:

• Only namespaces named under [dns.namespaces] answer at all; everything else in the database is NXDOMAIN, indistinguishable from a value that was never seen. Namespaces beginning with _ are refused at startup.
• The listener binds to 127.0.0.1 unless you say otherwise.
• Names outside the configured zone are REFUSED rather than answered, so this can never act as an open resolver.
• rate_limit caps queries per second per source address, dropping rather than refusing once a source is over budget — an error reply is still an amplified packet. Responses are capped at 1232 bytes even if a client advertises more.
• Shadow sightings are off by default, since over DNS they would be an unauthenticated write path.

Management interface

Point a browser at /_management/ and sign in with an API key holding the admin grant — changeme on a fresh install:

[acl]
changeme   = "rw, admin"
feeds-only = "admin, r:feeds"

It lists namespaces, browses the values inside one namespace (paged and filterable, since a namespace can hold a great many), and draws a histogram of when a value was seen from the hourly statistics the database already keeps. /_management/feeds/ips/ is a direct link to that namespace, so views are bookmarkable.

Access is two-layered. The admin grant is what reaches the interface at all; ordinary read grants then decide which namespaces are visible inside it. In the example above, feeds-only signs in but sees only feeds/* — everything else answers 404, the same as a namespace that does not exist, so browsing cannot be used to enumerate what is out of reach.

An admin key is required even when authenticate = false. Turning authentication off is a decision about the sighting API; it should not hand the management interface to anyone who can reach the port.

The configuration view is read-only: settings are read from the file at startup, so changing them means editing the file and restarting. The interface reports what the server is actually doing rather than pretending to edit it.

Charts use Apache ECharts, vendored into the binary rather than loaded from a CDN so the interface works on a host with no internet access. See assets/README.md.

Importing

ZeroMQ

SightingDB can subscribe to a ZeroMQ publisher and record what it hears. The usual source is MISP, whose publisher sends <topic> <json> frames:

[zmq]
endpoint = "tcp://misp.example.com:50000"
topics = ["misp_json_attribute", "misp_json"]
format = "misp"
require_to_ids = true

[zmq.types]
ip-src = "misp/ips"
domain = "misp/domains"
md5 = "misp/hashes"

Attributes are read from misp_json_attribute, and from whole events on misp_json including attributes nested inside objects. Only mapped types are ingested unless default_namespace is set, MISP's own timestamps are preserved, and require_to_ids=true limits ingest to attributes MISP flagged as actionable. A publisher that goes away is retried rather than being fatal.

format=native instead reads {"items":[{"namespace":..,"value":..}]}, for publishers that speak SightingDB directly. Note that in this mode the publisher chooses its own namespaces, so only subscribe to a source you trust — the _config tree is refused, but nothing else is.

This uses a native Rust ZeroMQ implementation, so the release binaries stay self-contained; it interoperates with libzmq publishers like MISP's.

STIX 2.1

$ sightingdb -c /etc/sightingdb/sightingdb.toml --import-stix bundles/

Reads one file or every .json in a directory, then exits. Three kinds of object are understood:

• observed-data — number_observed observations between first_observed and last_observed, following object_refs (and the deprecated embedded objects).
• sighting — its count and first_seen/last_seen, resolving sighting_of_ref and observed_data_refs.
• indicator — the literal values in its STIX pattern.

Counts and windows survive the import: an observed-data seen 12 times between two instants becomes a value with count=12 whose first_seen and last_seen bracket that window. A file object yields one sighting per hash. A bundle that fails to parse is reported and skipped so the rest of the import continues.

Access control

API keys and what each may reach are declared in an [acl] section:

[acl]
admin     = "rw, admin"
analyst   = "r"
feed-misp = "rw:feeds/misp"
mixed     = "r, w:staging"

Each entry is <apikey> = <grant>[, <grant>...]. A grant is r, w or rw, optionally scoped with :<namespace prefix>; without a prefix it covers every namespace. A key's grants are unioned, and anything not granted is denied.

Prefixes match whole path segments, so rw:feeds/misp covers feeds/misp and feeds/misp/ips but not feeds/misp-internal or feeds.

A refusal is always 403 with the same body whether the key is unknown or merely out of scope, so that probing cannot tell valid keys from invalid ones.

-k <key> still overrides everything with a single full-access key, replacing the built-in changeme.

Keys are stored in the configuration in the clear. Keep that file readable only by the user the daemon runs as, and serve over TLS.

Upgrading

Older versions kept API keys in the database and gave every key full access to everything. If the configuration has no [acl] section, keys restored from a snapshot keep exactly that access, so upgrading does not lock out a running deployment — the daemon logs a warning telling you to scope them. Adding an [acl] section makes it authoritative, and the keys in the snapshot are then ignored.

Persistence

The database is written to <dbdir>/sightingdb.json every snapshot_interval seconds and once more on a clean shutdown. Snapshots are written to a temporary file and renamed into place, so a crash mid-write leaves the previous snapshot intact rather than a truncated one; at most snapshot_interval seconds of writes are at risk.

A snapshot that exists but cannot be parsed is a fatal startup error rather than a silent fresh start, since starting empty would look like total data loss and the next save would make it real.

API keys are not in the snapshot: they come from the configuration, so permissions are reviewable and can live in version control.

Tests

cargo test

tests/ also holds Python scripts that exercise a running server; they require the SightingDB Python client library.