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vyper performs incorrect topic logging in raw_log

Moderate severity GitHub Reviewed Published Apr 25, 2024 in vyperlang/vyper • Updated Jun 18, 2024

Package

pip vyper (pip)

Affected versions

< 0.4.0

Patched versions

0.4.0

Description

Summary

Incorrect values can be logged when raw_log builtin is called with memory or storage arguments to be used as topics.

A contract search was performed and no vulnerable contracts were found in production. In particular, no uses of raw_log() were found at all in production; it is apparently not a well-known function.

Details

The build_IR function of the RawLog class fails to properly unwrap the variables provided as topics. Consequently, incorrect values are logged as topics.

PoC

x: bytes32

@external
def f():
    self.x = 0x1234567890123456789012345678901234567890123456789012345678901234
    raw_log([self.x], b"") # LOG1(offset:0x60, size:0x00, topic1:0x00)

    y: bytes32 = 0x1234567890123456789012345678901234567890123456789012345678901234
    raw_log([y], b"") # LOG1(offset:0x80, size:0x00, topic1:0x40)

Patches

Fixed in vyperlang/vyper#3977.

Impact

Incorrect values can be logged which may result in unexpected behavior in client-side applications relying on these logs.

References

@charles-cooper charles-cooper published to vyperlang/vyper Apr 25, 2024
Published by the National Vulnerability Database Apr 25, 2024
Published to the GitHub Advisory Database Apr 25, 2024
Reviewed Apr 25, 2024
Last updated Jun 18, 2024

Severity

Moderate

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
Low
Availability
None

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

EPSS score

0.043%
(10th percentile)

Weaknesses

CVE ID

CVE-2024-32645

GHSA ID

GHSA-xchq-w5r3-4wg3

Source code

Credits

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