# CVE-2018-17071: Business logic in n/a

> Attackers can predict lottery outcomes and buy tickets cheaply due to flawed randomness and pricing logic in the Lucky9io smart contract.

- **Severity:** High 7.5 (`CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 18 Sep 2018
- **Updated:** 5 Aug 2024
- **Also known as:** GHSA-f52j-f76h-vc62

## What is CVE-2018-17071?

CVE-2018-17071 is a high-severity vulnerability in n/a, published on 18 Sep 2018. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

The fallback function of a simple lottery smart contract implementation for Lucky9io, an Ethereum gambling game, generates a random value with the publicly readable variable entry_number. This variable is private, yet it is readable by eth.getStorageAt function. Also, attackers can purchase a ticket at a low price by directly calling the fallback function with small msg.value, because the developer set the currency unit incorrectly. Therefore, it allows attackers to always win and get rewards.

Weakness: CWE-338 (Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG))

## Which versions are affected by CVE-2018-17071?

It affects 1 product.


Products: Lucky9 Lucky9io.

## How do I fix CVE-2018-17071?

No fix has been published for CVE-2018-17071 yet. Limit exposure of the affected software until one is available.

## Is CVE-2018-17071 being exploited?

There is no known exploitation of CVE-2018-17071 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2018-17071 and fix it if it is affected.

What it is: CVE-2018-17071 is a high-severity vulnerability in n/a, published on 18 Sep 2018. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2018-17071 in the wild and no public exploit code.

Affected product: n/a. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2018-17071/ (Markdown: https://insights.sbomify.com/CVE-2018-17071/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-17071
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-17071
- OSV: https://osv.dev/vulnerability/CVE-2018-17071

---
From sbomify Insights: https://insights.sbomify.com/CVE-2018-17071/
Summaries are generated and may contain mistakes; the official description above is the record.