`_delete_files()` takes no parameters. CVE-2023-6559 arrives as a FIELD,
written by one method and read by another:
public function __construct( ..., array $attachments = array() )
$this->attachments = $attachments; // half one ends here
protected function _delete_files()
foreach ( $this->attachments as $file ) // half two starts here
unlink( $file );
Both halves were already in the graph. Only the join was missing, and the key
it joins on is the literal `$this->attachments`, written identically at both
ends -- so this is a second question asked with the query that already exists,
not an edge a frontend has to invent.
A read of `$this->F` is a source when some assignment to the same literal
`$this->F` in the same file is fed by an unsanitized flow from a seed. Scoped
three ways so a field name common to every class ever written cannot become a
wormhole: only fields the sink scope reads, only assignments in the same file,
and the right-hand side must itself be reachable from a source.
The receiver could then leave `parameterNodes` -- the precision fix refused
two commits ago, now sound, because the path it was standing in for is carried
by the field it actually travels through:
before after
mwwpform vulnerable 1, from `this` 1, from $this->attachments
mwwpform fixed 0 0
pmpro vulnerable 15 -- 4 named, 11 receiver 18 -- all named or field
pmpro fixed 1, receiver-sourced 1
VAmPI 4 entailed 4 entailed, unchanged
CVE-2023-23488 is still at class.memberorder.php:936 and CVE-2023-6559 at
class.mail.php:259. Every finding now names the value it followed instead of
naming the object.
Three things cost a measurement each, recorded in the task:
* A summary must carry the SANITIZATION status of the half it summarises,
not merely its reachability. Without that clause,
`$this->sqlQuery = "..." . esc_sql($x) . "..."` reads as tainted -- and
PMPro builds most of its queries that way, so the fixed side went from 1
finding to 13. That is the pair no longer separating, which is the only
number that matters.
* Two-phase `reachableBy` then `reachableByFlows` is SLOWER, not faster:
183s -> 256s. Running the analysis twice costs more than skipping path
reconstruction saves. Reverted.
* Memoizing per field rather than per file took it to 97s, about 1.6x the
pre-field cost for that class, because only fields some region reads are
worth the flow query.
`inScope` is factored out of `sinkCalls` so the field sources are scoped to
exactly the same place as the sinks, rather than a second copy of those three
branches drifting from the first.
841 tests pass; gates byte-identical; VAmPI unchanged.
Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>
Claude-Session: https://claude.ai/code/session_01T7XD7x5KonMdmGRkp63EQG
13 KiB
Pinned known-vulnerable checkouts
The pair corpus scores excerpts: a vulnerable function and its fixed twin, fifteen lines each, handed to the engine with the answer already narrowed down. That measures arbitration. It cannot measure anything about a repository — region ranking, the budget, one CPG over thousands of files, or whether a verdict that holds on an excerpt still holds when the source, the sink and the guard live in three different modules.
These recipes name real checkouts so those questions can be measured instead of assumed.
What a recipe is
One TOML file per repository, naming a url, a full 40-character commit SHA, the licence, and every known vulnerability with the file, function and line it lives at.
ousast repos # what is pinned, and whether it is checked out
ousast repos --repo vampi --fetch # materialise one (network; CI never does this)
ousast repos --json # the same, for an artifact
Nothing here is vendored. The repositories stay in their own projects under their own licences; the recipe records the licence so a measurement artifact can say what it ran against.
Three rules, and why
Offline by default. A recipe is inert until someone asks for the network — --fetch for one run, or
OPENULTRASAST_REPOS_NETWORK=1. CI sets neither, and the test suite clears both. This is the same rule the
pointer pairs follow, for the same reason: a test suite that quietly reaches the network is a test suite that
fails for reasons that have nothing to do with the code.
Pinned, not tracked. commit must be a full SHA; a branch or a tag is rejected at load. A tag gets
re-cut and a branch moves every week, and either would make the same recipe mean different code next month
while the baseline it produced still carried the old numbers.
A recipe declares what it can measure. measures is detection, envelope, or both, and every known
vulnerability states in_scope explicitly — whether it belongs to a family this engine arbitrates at all.
There is no default, because the default would silently decide the most important question about the result:
An out-of-bounds read in a C library is a fine envelope test and an impossible detection test. Recording "not found" against it as a miss is the easiest way to make a measurement lie.
Verification
ousast repos does not trust a recipe. Against a materialised checkout it checks that HEAD is the pinned
commit, that the licence file is really there, and that each declared function appears above its declared
line in its declared file. A recipe that contradicts the code exits non-zero; a recipe that simply has not
been fetched does not, or CI could never run this command.
That check earned its place immediately: the first libpng recipe named LICENSE.md, which is the filename at
HEAD today and not at the pinned commit, where it is still LICENSE.
What is pinned
| repo | language | size | measures | why |
|---|---|---|---|---|
vampi |
python | 520 lines, 11 files | detection | Small enough that a detection result is not confounded by budget or ranking. Its routes are registered through an OpenAPI operationId rather than decorators, so it exercises registration-based entry-point mapping. Excerpts of it are already in the pair corpus, so a whole-repository run says directly whether a verdict survives the move off the excerpt. |
libpng |
c | 91k lines, 101 files | envelope | Whether one CPG over a real C library is affordable at all: build time, query time, peak memory, and whether the ranker yields a sane number of regions. Its CVE is out of scope by construction. |
pmpro |
php | 117k lines, 637 files | detection, envelope | Paid Memberships Pro 2.9.7. CVE-2023-23488 is an unauthenticated SQL injection whose value reaches the sink inside the function that receives it -- the shape the PHP fact tables were built for. 2.9.8 wraps it in $wpdb->prepare, so the pair separates. |
mwwpform |
php | MW WP Form 5.0.3 | detection | CVE-2023-6559, an arbitrary file deletion. The fix adds realpath(), is_file() and a directory-confinement test, all of which the facts already carry, so this is a pair the engine can separate rather than merely flag. |
wpstatistics |
php | WP Statistics 13.1.x | detection | CVE-2022-25148, an unauthenticated SQL injection that crosses add_filter/apply_filters. Pinned because it is NOT expected to be found: a table of hits teaches nothing about where the engine stops. |
WordPress, class by class
WordPress's recurring flaw classes are narrow and well documented, which makes them a fair test: each one maps to a family this engine already has, so "not found" has to name a mechanism rather than shrug. Three plugins, each pinned at a version whose advisory was read out of the code and not out of the advisory text, and each measured against its own fixed commit.
| class | plugin, CVE | vulnerable side | fixed side | verdict |
|---|---|---|---|---|
| Unauthenticated injection, sink in the function that receives the value | pmpro, CVE-2023-23488 |
entailed at class.memberorder.php:936:getMemberOrderByCode, sourced from $code |
absent | found, and the pair separates |
| Arbitrary file operation | mwwpform, CVE-2023-6559 |
entailed at class.mail.php:259:_delete_files |
absent | found, and the pair separates |
| Unauthenticated injection, value crosses a WordPress hook | wpstatistics, CVE-2022-25148 |
not reported | not reported | missed, structurally |
| Missing capability check | — | — | — | cannot be asked: PHP has no obligation facts |
| Unescaped output | — | — | — | cannot be trusted: the sanitizer list is flat |
The two it finds
Both are entailed by the graph alone — no judge, no model call, no spend — and both disappear on the fixed
side because the fix is a call the fact tables already carry: $wpdb->prepare for one, realpath() for the
other. That is the distinction worth teaching. The engine is not recognising a bug; it is failing to find a
cleansing call on a path it resolved, and then finding one.
Every finding now names the value it followed. On PMPro's order class the vulnerable side reports 18
entailed findings and the fixed side 1, and each one is sourced either from a named parameter ($id,
$code, $token) or from a named field ($this->sqlQuery, $this->Email). None is sourced from $this.
That took two changes, and the order between them is the whole point. Excluding the receiver from parameter
sources was tried first and reverted: it cuts the file to 6 findings and makes the pair separate cleanly,
and it loses CVE-2023-6559, because _delete_files() takes no parameters at all and its
attacker-controlled path arrives as $this->attachments, assigned by another method entirely. Trading a
verified CVE for findings merely suspected of being false is the wrong trade.
With the field half of the join in place (below), that path is carried by the field it actually travels through, and the receiver no longer has to stand in for it — so it can go, and the eleven receiver-sourced findings go with it. The precision fix became available once the mechanism underneath it was right.
The one it misses, and why
WP Statistics' CVE is an unauthenticated REST hit whose current_page_id is interpolated into
$wpdb->get_row. Every piece is in scope — a modelled source, a modelled sink, and esc_sql as the fix —
and the engine still reports nothing, on both sides. The reason is checkable rather than inferred:
-
the file holding the sink contains zero superglobals;
-
it makes no call into the class holding the source;
-
the only connection between them is
add_filter('wp_statistics_current_page', array($this, 'set_current_page')); // hits.php:43 return apply_filters('wp_statistics_current_page', $current_page); // pages.php:105
Both ends name the callback with a string. No frontend can draw that edge, so no dataflow engine can cross it, and the honest description is not "we missed it" but "the graph does not contain the path". Most plugin data travels this way. It is the single largest structural gap for PHP, and it is not a fact-table problem.
It is also not a permanent one, and "structurally impossible" would be the wrong thing to leave here. Note
what is and is not missing: $_REQUEST reaching set_current_page's return is a path the graph has, and
apply_filters' return reaching $wpdb->get_row is a path the graph has. Only the join between them is
absent — and the key it joins on, 'wp_statistics_current_page', is a string literal written at both ends.
The same is true of $this->attachments in MW WP Form, where the key is a field name.
So the strategy is two-stage taint with a link table: ask the existing query for each half against a synthetic endpoint, build the table by reading literals rather than inferring anything, and join. The rung carries the join's uncertainty — one registered callback and a literal key entails, several callbacks or a computed hook name corroborates. Task 5.11 states it, with both pinned pairs as its observable.
The field half is implemented and measured. $this->attachments is tainted at the assignment that fills
it, joined to the read by the literal field code, so CVE-2023-6559 is found as
class.mail.php:259:_delete_files ← $this->attachments and is absent on the fixed side. One thing it needed
that is easy to get wrong: the summary has to carry the sanitization status of the half it summarises,
not merely its reachability. Asking only "does a source reach this assignment" marks
$this->sqlQuery = "..." . esc_sql($x) . "..." tainted, and PMPro builds most of its queries that way — the
fixed side went from 1 finding to 13 before that clause existed, which is the pair no longer separating at
all. It costs about 1.6× on the taint query for that class (62s → 97s), memoised per field.
The hook half is the same machinery against a different key, and is not written yet.
What the engine reports on that plugin instead is two other sites — getTop:406 and TotalCount:443 — the
same weakness class at the wrong lines, identical on both sides, so the pair does not separate. They are not
noise: upstream now annotates both with // phpcs:ignore WordPress.DB.PreparedSQL..., and later rewrote
one of them with $wpdb->prepare. Right class, wrong sites, no discrimination.
The two it cannot ask
dominance_specs(language="php") returns an empty mapping. There are no PHP obligation facts, so the
missing-capability class — current_user_can, check_admin_referer — is never asked, on any plugin, and
would report nothing however many were added. That is not a miss; nothing was measured. Recorded as 5.9.
output_encoding for PHP has sinks (echo, print, printf) and shares the one flat sanitizer list
with every other family. That list contains esc_sql, intval, realpath and escapeshellarg, none of
which escape HTML, and excludes esc_html and esc_attr, which are the only ones that do. So it is wrong in
both directions at once: it would accept echo esc_sql($x) as safe and report
echo esc_attr(sanitize_text_field($_REQUEST['login'])) — the pattern WordPress documents as correct, and
which appears verbatim at pmpro/includes/login.php:684 — as a finding. Until a sanitizer can say which
weakness class it cleanses, no XSS verdict from this engine means anything. Recorded as 5.6.
What nearly invalidated all of it
The first PMPro measurement in this series reported 64 regions examined, zero findings and zero degradations. The graph it examined had no methods in it.
php2cpg 4.0.623 reads its PHP parser's stdout and stderr as one merged stream, and the parser writes a
progress banner to stderr the moment it starts the next file — while the previous file's multi-megabyte JSON
is still draining from a block-buffered stdout. The banner lands inside the JSON, the file is dropped, and
joern-parse propagates none of it: thirteen lines of output, exit status 0, "Successfully wrote graph".
One oversized file empties the entire graph, so this was never the scale limit it looked like.
It is also a race, not a threshold. Five builds of the same two-file input: three produced a graph, two came back empty. Before the batched query started carrying a census of the graph, two of every five scans of that plugin would have reported a clean bill of health.
That is the argument for why a corpus of benchmarks is not enough on its own, made concretely. Every gate stayed byte-identical through all of it. A corpus tells you a verdict is right; it cannot tell you the verdict was reached by looking at anything.
Baselines
Task 6.1 turns a scan of a pinned checkout into a committed baseline, so a change to the fact tables or the queries can be read as findings gained, findings lost and rung movements (Req 10.1–10.4). Until then these recipes exist to be measured against by hand, and the first such measurement is task 2.2.