# CVE-2022-25218: Weak cryptography in Phicomm Routers

> Unauthenticated attackers can exploit weak RSA padding in telnetd to achieve root shell access on Phicomm routers via crafted UDP packets.

- **Severity:** High 8.1 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 7 Mar 2022
- **Updated:** 3 Aug 2024
- **Also known as:** GHSA-j9f3-j4r5-j83v

## What is CVE-2022-25218?

CVE-2022-25218 is a high-severity vulnerability in Phicomm Routers, published on 7 Mar 2022. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

The use of the RSA algorithm without OAEP, or any other padding scheme, in telnetd_startup, allows an unauthenticated attacker on the local area network to achieve a significant degree of control over the "plaintext" to which an arbitrary blob of ciphertext will be decrypted by OpenSSL's RSA_public_decrypt() function. This weakness allows the attacker to manipulate the various iterations of the telnetd startup state machine and eventually obtain a root shell on the device, by means of an exchange of crafted UDP packets. In all versions but K2 22.5.9.163 and K3C 32.1.15.93 a successful attack also requires the exploitation of a null-byte interaction error (CVE-2022-25219).

Weakness: CWE-327 (Use of a Broken or Risky Cryptographic Algorithm)

## Which versions are affected by CVE-2022-25218?

It affects 5 products.


Products: Phicomm K2 Firmware, Phicomm K2g Firmware, Phicomm K2p Firmware, Phicomm K3 Firmware, Phicomm K3c Firmware.

## How do I fix CVE-2022-25218?

No fix has been published for CVE-2022-25218 yet. Limit exposure of the affected software until one is available.

## Is CVE-2022-25218 being exploited?

There is no known exploitation of CVE-2022-25218 in the wild and no public exploit code.

## Other vulnerabilities in Phicomm Routers

- [CVE-2022-25219](https://insights.sbomify.com/CVE-2022-25219/): Weak cryptography in Phicomm Routers (high 8.4)
- [CVE-2023-40796](https://insights.sbomify.com/CVE-2023-40796/): Command injection in n/a (high 7.8)
- [CVE-2022-48070](https://insights.sbomify.com/CVE-2022-48070/): Command injection in n/a (high 7.8)
- [CVE-2022-48072](https://insights.sbomify.com/CVE-2022-48072/): Command injection in n/a (high 7.8)
- [CVE-2022-25217](https://insights.sbomify.com/CVE-2022-25217/): Hardcoded credentials in Phicomm Routers (high 7.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2022-25218 and fix it if it is affected.

What it is: CVE-2022-25218 is a high-severity vulnerability in Phicomm Routers, published on 7 Mar 2022. 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-2022-25218 in the wild and no public exploit code.

Affected product: Phicomm Routers. 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-2022-25218/ (Markdown: https://insights.sbomify.com/CVE-2022-25218/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2022-25218
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2022-25218
- OSV: https://osv.dev/vulnerability/CVE-2022-25218

---
From sbomify Insights: https://insights.sbomify.com/CVE-2022-25218/
Summaries are generated and may contain mistakes; the official description above is the record.