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Submission Details
Severity: medium
Invalid

Potential Staleness Vulnerability in `QuantAMMWeightedPool` Contract

rolando

Summary

The QuantAMMWeightedPool contract currently does not reject weight updates when the oracle data is stale. As a result, any party calling the UpdateWeightRunner can force changes to pool weights based on outdated (stale) oracle information. This gap breaks critical assumptions regarding fresh pricing or time-based weight interpolation.

By allowing stale data to drive weight updates, the protocol may face:

  1. Financial Losses: Malicious or erroneous updates could manipulate token weights, creating unexpected or abusive trading conditions.

  2. Operational Issues: The system’s logic (e.g., time-based interpolation or rebalancing) is undermined if it operates on old data.

  3. Erosion of Trust: Users relying on accurate, up-to-date pool behavior may lose confidence when stale data triggers harmful rebalances or price misalignments.

Vulnerability Details

Root Cause

In the setWeights(...) function of QuantAMMWeightedPool, there is no check enforcing a maximum age (staleness threshold) for oracle data.

The contract simply assumes that all calls from the UpdateWeightRunner are based on fresh prices or time updates.

Consequently, even if the last oracle update occurred far beyond the intended threshold, the pool will still accept the new weights.

QuantAMMWeightedPool.sol - setWeights

Impact

Direct Exploit: An attacker who can supply or manipulate outdated oracle data could push weights favoring certain tokens.

Systemic Risk: If large price swings happen in reality but the pool uses stale data, the weights can shift drastically away from safe allocations, possibly causing heavy arbitrage losses or incorrect margining.

Loss of Functionality: Even if no malicious actor is present, a misconfigured or offline oracle can lead to inaccurate weights, diminishing the protocol's reliability.

Proof of Concept

Test Demonstration of No Revert on Stale Data

Add the following test to pkg/pool-quantamm/test/foundry/QuantAMMWeightedPool2Token.t.sol:

Below is a simplified test scenario demonstrating how QuantAMMWeightedPool updates weights despite the oracle being stale:

/// @notice Demonstrates that the pool doesn’t revert despite a “stale” oracle
function test_OracleStalenessThresholdBug() public {
// 1) Print a header so we see it clearly in logs
console2.log('--- test_OracleStalenessThresholdBug START ---');
​
// 2) Create a new Pool with an oracleStalenessThreshold = 3600 (e.g., 1 hour).
// We'll reuse _createPoolParams() and just rely on the default "params._oracleStalenessThreshold" from
// the factory, or set it right after creation if needed.
​
// We'll build a minimal scenario: 2 tokens, each 0.5 weight, and we'll forcibly warp time beyond the threshold.
​
// Create a standard 2-token pool from the factory
QuantAMMWeightedPoolFactory.NewPoolParams memory params = _createPoolParams();
​
// (optionally adjust `params._oracleStalenessThreshold` if your code uses that pattern;
// for demonstration, we rely on the default 3600 in the _createPoolParams or in the pool's initialize.)
​
(address quantAMMWeightedPool, ) = quantAMMWeightedPoolFactory.create(params);
​
// 3) We'll set some initial weights (0.5, 0.5) or rely on the default from _createPoolParams
// Then set them again after warping time to prove no revert occurs with stale data.
int256[] memory newWeights = new int256[]();
newWeights[0] = 0.6e18; // weight for token0
newWeights[1] = 0.4e18; // weight for token1
newWeights[2] = 0; // blockMultiplier0
newWeights[3] = 0; // blockMultiplier1
​
// 4) Call setWeights from the runner (since the pool requires runner as msg.sender)
console2.log('Setting weights to (0.6, 0.4) initially...');
vm.prank(address(updateWeightRunner));
QuantAMMWeightedPool(quantAMMWeightedPool).setWeights(
newWeights,
quantAMMWeightedPool,
uint40(block.timestamp + 5)
);
​
// 5) Confirm the weights are updated
{
uint256[] memory initialWeights = QuantAMMWeightedPool(quantAMMWeightedPool)
.getNormalizedWeights();
console2.log('Initial w0 =', initialWeights[0]);
console2.log('Initial w1 =', initialWeights[1]);
// Typically we do: assertEq(initialWeights[0], 0.6e18) etc.
}
​
// 6) Warp time by 2 hours (7200s) => Oracle data is now stale if threshold=3600.
console2.log('Warping time by 7200 seconds => stale oracle data');
vm.warp(block.timestamp + 7200);
​
// 7) Attempt to set new weights with stale data.
int256[] memory staleWeights = new int256[]();
staleWeights[0] = 0.7e18; // new weight for token0
staleWeights[1] = 0.3e18; // new weight for token1
staleWeights[2] = 0; // blockMultiplier0
staleWeights[3] = 0; // blockMultiplier1
​
console2.log('Setting weights to (0.7, 0.3) despite stale oracle...');
// Expecting NO revert => shows the vulnerability
vm.prank(address(updateWeightRunner));
QuantAMMWeightedPool(quantAMMWeightedPool).setWeights(
staleWeights,
quantAMMWeightedPool,
uint40(block.timestamp + 100)
);
​
// 8) Check final weights => see that the pool accepts them without any staleness check
uint256[] memory finalWeights = QuantAMMWeightedPool(quantAMMWeightedPool)
.getNormalizedWeights();
console2.log('Final w0 =', finalWeights[0]);
console2.log('Final w1 =', finalWeights[1]);
​
// 9) If the pool had a proper staleness check, it would revert. Instead, we see the update succeed.
// We can add an assert to confirm it changed, proving the vulnerability:
assertEq(
finalWeights[0],
0.7e18,
'Pool accepted weight 0.7 despite stale oracle'
);
assertEq(
finalWeights[1],
0.3e18,
'Pool accepted weight 0.3 despite stale oracle'
);
​
console2.log('--- test_OracleStalenessThresholdBug FINISHED ---\n');
}

Test Result

Logs:
--- test_OracleStalenessThresholdBug START ---
Setting weights to (0.6, 0.4) initially...
Initial w0 = 600000000000000000
Initial w1 = 400000000000000000
Warping time by 7200 seconds => stale oracle data
Setting weights to (0.7, 0.3) despite stale oracle...
Final w0 = 700000000000000000
Final w1 = 300000000000000000
--- test_OracleStalenessThresholdBug FINISHED ---

Result:
This test confirms that, even if we advance time beyond the staleness threshold (7200s > 3600s), the contract does not revert. The pool updates the weights (from 0.6/0.4 to 0.7/0.3) without any freshness check, showing that stale data is accepted and highlighting the vulnerability.

Fuzz test

Add the following test to pkg/pool-quantamm/test/foundry/QuantAMMWeightedPool2Token.t.sol:

function testFuzzOracleStalenessThresholdBug(
uint256 warpSeconds,
int256 weight0,
int256 weight1
) public {
// 1) Bound warpSeconds
warpSeconds = bound(warpSeconds, 0, 100000);
​
// 2) Bound the weights to [0 .. 1e18]
weight0 = boundInt(weight0, 0, 1e18);
weight1 = boundInt(weight1, 0, 1e18);
​
// If total != 1e18, skip
if (weight0 + weight1 != 1e18) {
return;
}
​
// 3) Create & deploy pool
QuantAMMWeightedPoolFactory.NewPoolParams memory params = _createPoolParams();
(address quantAMMWeightedPool, ) = quantAMMWeightedPoolFactory.create(params);
​
// 4) Set initial weights (0.5, 0.5)
int256[] memory initialWeights = new int256[]();
initialWeights[0] = 0.5e18;
initialWeights[1] = 0.5e18;
initialWeights[2] = 0;
initialWeights[3] = 0;
​
vm.prank(address(updateWeightRunner));
QuantAMMWeightedPool(quantAMMWeightedPool).setWeights(
initialWeights,
quantAMMWeightedPool,
uint40(block.timestamp + 1000)
);
​
// 5) Warp time
vm.warp(block.timestamp + warpSeconds);
​
// 6) Attempt new weights (weight0, weight1) with no staleness check
int256[] memory newWeights = new int256[]();
newWeights[0] = weight0;
newWeights[1] = weight1;
newWeights[2] = 0;
newWeights[3] = 0;
​
vm.prank(address(updateWeightRunner));
QuantAMMWeightedPool(quantAMMWeightedPool).setWeights(
newWeights,
quantAMMWeightedPool,
uint40(block.timestamp + 1000)
);
​
// 7) Final check
uint256[] memory finalWeights = QuantAMMWeightedPool(quantAMMWeightedPool)
.getNormalizedWeights();
assertEq(
finalWeights[0],
uint256(int256(weight0)),
'Mismatch w0 (stale oracle fuzz)'
);
assertEq(
finalWeights[1],
uint256(int256(weight1)),
'Mismatch w1 (stale oracle fuzz)'
);
}
​
/**
* @dev Helper to bound int256 in [minVal .. maxVal].
* This is similar to Foundry's bound, but for signed numbers.
*/
function boundInt(
int256 x,
int256 minVal,
int256 maxVal
) internal pure returns (int256) {
require(minVal <= maxVal, 'Invalid bounds');
if (x < minVal) return minVal;
if (x > maxVal) return maxVal;
return x;
}

Test Result

[PASS] testFuzzOracleStalenessThresholdBug(uint256,int256,int256) (runs: 10003, μ: 2915236, ~: 4790)
Traces:
[4119] QuantAMMWeightedPool2TokenTest::testFuzzOracleStalenessThresholdBug(6069, 3682693511 [3.682e9], 194)
├─ [0] console::log("Bound Result", 6069) [staticcall]
│ └─ ← [Stop]
└─ ← [Stop]
​
Suite result: ok. 1 passed; 0 failed; 0 skipped; finished in 5.56s (5.50s CPU time)

Result:
The fuzz test shows that, for a wide range of warpSeconds values (up to 100,000) and weights summing to 1e18 (between 0 and 1e18), the pool does not revert due to stale data. After each time warp, weight update calls succeed. This reinforces the conclusion that no staleness validation exists and that the pool accepts updates even under “stale oracle” conditions.

Tools Used

Foundry: Used to develop and run tests to validate the vulnerability.
Manual Code Review: Confirmed the issue exists in the setWeights(...) function and related logic.

Recommendations

Mitigation

  1. Add a Staleness Check in setWeights(...):
    Implement a require(...) statement to validate the freshness of the oracle data before proceeding with weight updates:

    require(
    block.timestamp - lastOracleUpdateTime <= oracleStalenessThreshold,
    "Oracle is stale"
    );

  2. Track Oracle Updates:
    Introduce a lastOracleUpdateTime variable in the pool and ensure it is updated whenever the oracle data is refreshed. Use the UpdateWeightRunner to call a function like refreshOracleTimestamp() on the pool to update the timestamp.

Example Mitigation Code

function setWeights(
int256[] calldata _weights,
address _poolAddress,
uint40 _lastInterpolationTimePossible
) external override {
require(msg.sender == address(updateWeightRunner), "ONLYUPDW");
require(_weights.length == _totalTokens * 2, "WLDL");
​
// Ensure oracle data is fresh
require(
block.timestamp - lastOracleUpdateTime <= oracleStalenessThreshold,
"Oracle is stale"
);
​
// (rest of weight update logic remains unchanged)
...
}

Validation Through Testing

After adding the recommended mitigations to the QuantAMMWeightedPool contract, include the following test in pkg/pool-quantamm/test/foundry/QuantAMMWeightedPool2Token.t.sol:

function test_RevertsWhenOracleStale() public {
console2.log('=== test_RevertsWhenOracleStale START ===');
​
// 1) Deploy or create the pool with an oracleStalenessThreshold (e.g., 3600).
// For simplicity, we’ll rely on whatever logic your _createPoolParams() uses
// or do the minimal steps here. Then we'll finalize by calling setWeights
// after we warp time beyond that threshold.
​
// (A) Create default pool params with staleness threshold = 3600
QuantAMMWeightedPoolFactory.NewPoolParams memory params = _createPoolParams();
// e.g., if your _createPoolParams sets 'params._oracleStalenessThreshold = 3600;'
​
// (B) Deploy the pool
(address quantAMMWeightedPool, ) = quantAMMWeightedPoolFactory.create(params);
​
// 2) Confirm initial conditions or logs
console2.log('Deployed pool at:', quantAMMWeightedPool);
console2.log(
"Expecting 'Oracle is stale' revert if we warp time beyond 3600 seconds."
);
​
// 3) Warp time by more than the threshold => 7200 seconds
​
console2.log(
'Warping chain time by 7200 secs to exceed staleness threshold...'
);
vm.warp(block.timestamp + 7200);
​
// 4) Prepare a new weight update
// We'll attempt setting (0.7, 0.3) or any other arbitrary distribution,
// and the pool will revert due to the new 'require(...)' check.
​
int256[] memory staleWeights = new int256[]();
// 2 tokens => we store [weight0, weight1, blockMultiplier0, blockMultiplier1]
staleWeights[0] = 0.7e18;
staleWeights[1] = 0.3e18;
staleWeights[2] = 0;
staleWeights[3] = 0;
​
console2.log('Attempting to set weights after time warp...');
​
// 5) Expect revert with "Oracle is stale"
​
vm.expectRevert('Oracle is stale');
​
// Since the pool requires msg.sender == updateWeightRunner, we prank the runner
vm.prank(address(updateWeightRunner));
QuantAMMWeightedPool(quantAMMWeightedPool).setWeights(
staleWeights,
quantAMMWeightedPool,
uint40(block.timestamp + 100)
);
​
console2.log('TEST PASSED => Revert occurred as expected');
console2.log('=== test_RevertsWhenOracleStale FINISHED ===\n');
}

Test Result

Logs:
=== test_RevertsWhenOracleStale START ===
Deployed pool at: 0x4Bc2f75371E5d3367E5D1E02F30080222F24B327
Expecting 'Oracle is stale' revert if we warp time beyond 3600 seconds.
Warping chain time by 7200 secs to exceed staleness threshold...
Attempting to set weights after time warp...
TEST PASSED => Revert occurred as expected
=== test_RevertsWhenOracleStale FINISHED ===

Result:
This test demonstrates that, after advancing time beyond the staleness threshold (7200s > 3600s), any attempt to update the weights reverts with the message "Oracle is stale". The revert confirms that the new verification implemented in QuantAMMWeightedPool.sol (the require(...) statement) prevents stale oracle data from being accepted, thereby validating the effectiveness of the mitigation.

Conclusion

Without a robust staleness check, QuantAMMWeightedPool is vulnerable to harmful weight changes based on outdated oracle data—whether accidental or malicious. By enforcing a maximum age for data, the protocol can effectively protect liquidity providers from price manipulations, ensure consistent weight interpolation, and uphold user trust.

Updates

Lead Judging Commences

n0kto Lead Judge 7 months ago
Submission Judgement Published
Invalidated
Reason: Incorrect statement

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