# CVE-2018-17877: Business logic in n/a

> Attackers can predict random values in the Greedy 599 gambling contract to always win rewards, bypassing anti-contract checks.

- **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:** 23 Oct 2018
- **Updated:** 5 Aug 2024
- **Also known as:** GHSA-qp5m-38pc-fmj4

## What is CVE-2018-17877?

CVE-2018-17877 is a high-severity vulnerability in n/a, published on 23 Oct 2018. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A lottery smart contract implementation for Greedy 599, an Ethereum gambling game, generates a random value that is predictable via an external contract call. The developer used the extcodesize() function to prevent a malicious contract from being called, but the attacker can bypass it by writing the core code in the constructor of their exploit code. 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-2018-17877?

It affects 1 product.


Products: Greedy599 Greedy 599.

## How do I fix CVE-2018-17877?

No fix has been published for CVE-2018-17877 yet. Limit exposure of the affected software until one is available.

## Is CVE-2018-17877 being exploited?

There is no known exploitation of CVE-2018-17877 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2018-17877 and fix it if it is affected.

What it is: CVE-2018-17877 is a high-severity vulnerability in n/a, published on 23 Oct 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-2018-17877 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-2018-17877/ (Markdown: https://insights.sbomify.com/CVE-2018-17877/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-17877
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-17877
- OSV: https://osv.dev/vulnerability/CVE-2018-17877

---
From sbomify Insights: https://insights.sbomify.com/CVE-2018-17877/
Summaries are generated and may contain mistakes; the official description above is the record.