# CVE-2015-8542: Auth bypass in n/a

> Attackers can bypass authentication to download other users' PGP private keys by exploiting predictable IDs and weak password hashing in Open-Xchange Guard.

- **Severity:** High 8.8 (`CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 15 Dec 2016
- **Updated:** 6 Aug 2024
- **Also known as:** GHSA-c9h2-cw5f-g747

## What is CVE-2015-8542?

CVE-2015-8542 is a high-severity authentication bypass vulnerability in n/a, published on 15 Dec 2016. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

An issue was discovered in Open-Xchange Guard before 2.2.0-rev8. The "getprivkeybyid" API call is used to download a PGP Private Key for a specific user after providing authentication credentials. Clients provide the "id" and "cid" parameter to specify the current user by its user- and context-ID. The "auth" parameter contains a hashed password string which gets created by the client by asking the user to enter his or her OX Guard password. This parameter is used as single point of authentication when accessing PGP Private Keys. In case a user has set the same password as another user, it is possible to download another user's PGP Private Key by iterating the "id" and "cid" parameters. This kind of attack would also be able by brute-forcing login credentials, but since the "id" and "cid" parameters are sequential they are much easier to predict than a user's login name. At the same time, there are some obvious insecure standard passwords that are widely used. A attacker could send the hashed representation of typically weak passwords and randomly fetch Private Key of matching accounts. The attack can be executed by both internal users and "guests" which use the external mail reader.

Weakness: CWE-320

## Which versions are affected by CVE-2015-8542?

It affects 1 product.


Products: Open-Xchange Ox Guard.

## How do I fix CVE-2015-8542?

No fix has been published for CVE-2015-8542 yet. Limit exposure of the affected software until one is available.

## Is CVE-2015-8542 being exploited?

There is no known exploitation of CVE-2015-8542 in the wild and no public exploit code.

## Other vulnerabilities in n/a

- [CVE-2018-10986](https://insights.sbomify.com/CVE-2018-10986/): OX Guard 2.8.0 has CSRF. (high 8.8)
- [CVE-2020-28944](https://insights.sbomify.com/CVE-2020-28944/): Denial of service in n/a (high 7.5)
- [CVE-2016-4028](https://insights.sbomify.com/CVE-2016-4028/): Weak cryptography in n/a (high 7.5)
- [CVE-2020-9426](https://insights.sbomify.com/CVE-2020-9426/): OX Guard 2.10.3 and earlier allows XSS. (medium 6.1)
- [CVE-2016-6851](https://insights.sbomify.com/CVE-2016-6851/): Cross-site scripting in n/a (medium 6.1)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2015-8542 and fix it if it is affected.

What it is: CVE-2015-8542 is a high-severity authentication bypass vulnerability in n/a, published on 15 Dec 2016. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2015-8542 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-2015-8542/ (Markdown: https://insights.sbomify.com/CVE-2015-8542/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2015-8542
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2015-8542
- OSV: https://osv.dev/vulnerability/CVE-2015-8542

---
From sbomify Insights: https://insights.sbomify.com/CVE-2015-8542/
Summaries are generated and may contain mistakes; the official description above is the record.