CVE-2023-40591: Vulnerability disclosure | go-ethereum

In the software world, it is expected for security vulnerabilities to be immediately announced, thus giving operators an opportunity to take protective measure against attackers.

Vulnerabilities typically take two forms:

1. Vulnerabilities that, if exploited, would harm the software operator. In the case of Geth, examples would be:

   • A bug that would allow remote reading or writing of OS files, or
   • Remote command execution, or
   • Bugs that would leak cryptographic keys

2. Vulnerabilities that, if exploited, would harm the Ethereum mainnet. In the case of Geth, examples would be:

   • Consensus vulnerabilities, which would cause a chain split,
   • Denial-of-service during block processing, whereby a malicious transaction could cause the geth-portion of the network to crash.
   • Denial-of-service via p2p networking, whereby portions of the network could be made inaccessible due to crashes or resource consumption.

In most cases so far, vulnerabilities in Geth have been of the second type, where the health of the network is a concern, rather than individual node operators. For such issues, Geth reserves the right to silently patch and ship fixes in new releases.

Why silent patches

In the case of Ethereum, it takes a lot of time (weeks, months) to get node operators to update even to a scheduled hard fork. If we were to highlight that a release contains important consensus or DoS fixes, there is always a risk of someone trying to beat node operators to the punch, and exploit the vulnerability. Delaying a potential attack sufficiently to make the majority of node operators immune may be worth the temporary loss of transparency.

The primary goal for the Geth team is the health of the Ethereum network as a whole, and the decision whether or not to publish details about a serious vulnerability boils down to minimizing the risk and/or impact of discovery and exploitation.

At certain times, it’s better to remain silent. This practice is also followed by other projects such as Monero, ZCash and Bitcoin.

Public transparency

As of November 2020, our policy going forward is:

• If we silently fix a vulnerability and include the fix in release X, then,
• After 4-8 weeks, we will disclose that X contained a security-fix.
• After an additional 4-8 weeks, we will publish the details about the vulnerability.

We hope that this provides sufficient balance between transparency versus the need for secrecy, and aids node operators and downstream projects in keeping up to date with what versions to run on their infrastructure.

In keeping with this policy, we have taken inspiration from Solidity bug disclosure - see below.

Disclosed vulnerabilities

There is a JSON-formatted list (vulnerabilities.json) of some of the known security-relevant vulnerabilities concerning Geth.

As of version 1.9.25, Geth has a built-in command to check whether it is affected by any publicly disclosed vulnerability, using the command geth version-check. This command will fetch the latest json file (and the accompanying signature-file, and cross-check the data against its own version number.

The list of vulnerabilities was started in November 2020, and covers mainly v1.9.7 and forward.

The JSON file of known vulnerabilities below is a list of objects, one for each vulnerability, with the following keys:

• name

  • Unique name given to the vulnerability.

• uid

  • Unique identifier of the vulnerability. Format GETH-<year>-<sequential id>

• summary

  • Short description of the vulnerability.

• description

  • Detailed description of the vulnerability.

• links

  • List of relevant URLs with more detailed information (optional).

• introduced

  • The first published Geth version that contained the vulnerability (optional).

• fixed

  • The first published Geth version that did not contain the vulnerability anymore.

• published

  • The date at which the vulnerability became known publicly (optional).

• severity

  • Severity of the vulnerability: low, medium, high, critical.
  • Takes into account the severity of impact and likelihood of exploitation.

• check

  • This field contains a regular expression, which can be used against the reported web3_clientVersion of a node. If the check matches, the node is with a high likelihood affected by the vulnerability.

• CVE

  • The assigned CVE identifier, if available (optional)

What about GitHub security advisories

We prefer to not rely on GitHub as the only/primary publishing protocol for security advisories, but we plan to use the GitHub-advisory process as a second channel for disseminating vulnerability-information.

Advisories published via GitHub can be accessed here.

Bug Bounties

The Ethereum Foundation run a bug bounty program to reward responsible disclosures of bugs in client software and specs. The details are provided on ethereum.org.