# GHSA-g753-jx37-7xwh: ECDSA signature vulnerability of Minerva timing attack in jsrsasign

> An attacker can recover ECDSA private keys by analyzing timing variations during signature generation in the jsrsasign library.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 30 Jun 2020

## What is GHSA-g753-jx37-7xwh?

GHSA-g753-jx37-7xwh is a vulnerability in jsrsasign, published on 30 Jun 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

### Impact
ECDSA side-channel attack named [Minerava](https://minerva.crocs.fi.muni.cz/) have been found and it was found that it affects to jsrsasign.

Execution time of thousands signature generation have been observed then EC private key which is scalar value may be recovered since point and scalar multiplication time depends on bits of scalar. In jsrsasign 8.0.13 or later, execution time of EC point and scalar multiplication is almost constant and fixed for the issue.

- Minerva is one of timing attack or side channel attack for EC.
- If you don't use ECDSA class, you are not affected the vulnerability.
- The vulnerability is that attacker may guess private key by checking processing time of EC key generation or ECDSA signing.
- The cause issue is that point multiplication processing time in ECDSA signing is depends on private key value.
- After 8.0.13, processing time of point multiplication in ECDSA signing have become constant for key value in theory.

### Patches
Users using ECDSA signature generation should upgrade to 8.0.13 or later.

### Workarounds
There is no workarounds in jsrsasign. Update jsrsasign or use other ECDSA library.

### ACKNOWLEDGEMENT
Thanks to Jan Jancar @J08nY, Petr Svenda and Vladimir Sedlacek of Masaryk University in Czech Republic to find and report this vulnerability.

### References
https://minerva.crocs.fi.muni.cz/
https://www.npmjs.com/advisories/1505
https://github.com/kjur/jsrsasign/issues/411

## Which versions are affected by GHSA-g753-jx37-7xwh?

2 open source packages ship an affected version, including jsrsasign.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `jsrsasign` | npm | From 4.0.0 | 8.0.13 |
| `jsrsasign` | npm | From 4.0.0 | 8.0.13 |

## How do I fix GHSA-g753-jx37-7xwh?

Upgrade jsrsasign to 8.0.13 or later.

## Is GHSA-g753-jx37-7xwh being exploited?

There is no known exploitation of GHSA-g753-jx37-7xwh in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for GHSA-g753-jx37-7xwh and fix it if it is affected.

What it is: GHSA-g753-jx37-7xwh is a vulnerability in jsrsasign, published on 30 Jun 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of GHSA-g753-jx37-7xwh in the wild and no public exploit code.

Affected packages and fixed versions:
- jsrsasign (npm): affected from 4.0.0; fixed in 8.0.13
- jsrsasign (npm): affected from 4.0.0; fixed in 8.0.13

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/GHSA-g753-jx37-7xwh/ (Markdown: https://insights.sbomify.com/GHSA-g753-jx37-7xwh/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/GHSA-g753-jx37-7xwh

---
From sbomify Insights: https://insights.sbomify.com/GHSA-g753-jx37-7xwh/
Summaries are generated and may contain mistakes; the official description above is the record.