Vulnerabilities

RUSTSEC-2023-0071

Marvin Attack: potential key recovery through timing sidechannels

Impact

Due to a non-constant-time implementation, information about the private key is leaked through timing information which is observable over the network. An attacker may be able to use that information to recover the key.

Patches

No patch is yet available, however work is underway to migrate to a fully constant-time implementation.

Workarounds

The only currently available workaround is to avoid using the rsa crate in settings where attackers are able to observe timing information, e.g. local use on a non-compromised computer is fine.

References

This vulnerability was discovered as part of the "Marvin Attack", which revealed several implementations of RSA including OpenSSL had not properly mitigated timing sidechannel attacks.

RUSTSEC-2024-0363

Binary Protocol Misinterpretation caused by Truncating or Overflowing Casts

The following presentation at this year's DEF CON was brought to our attention on the SQLx Discord:

> SQL Injection isn't Dead: Smuggling Queries at the Protocol Level
> <http://web.archive.org/web/20240812130923/https://media.defcon.org/DEF%20CON%2032/DEF%20CON%2032%20presentations/DEF%20CON%2032%20-%20Paul%20Gerste%20-%20SQL%20Injection%20Isn&#39;t%20Dead%20Smuggling%20Queries%20at%20the%20Protocol%20Level.pdf>
> (Archive link for posterity.)

Essentially, encoding a value larger than 4GiB can cause the length prefix in the protocol to overflow,
causing the server to interpret the rest of the string as binary protocol commands or other data.

It appears SQLx does perform truncating casts in a way that could be problematic,
for example: <https://github.com/launchbadge/sqlx/blob/6f2905695b9606b5f51b40ce10af63ac9e696bb8/sqlx-postgres/src/arguments.rs#L163>

This code has existed essentially since the beginning,
so it is reasonable to assume that all published versions <= 0.8.0 are affected.

Mitigation

As always, you should make sure your application is validating untrustworthy user input.
Reject any input over 4 GiB, or any input that could encode to a string longer than 4 GiB.
Dynamically built queries are also potentially problematic if it pushes the message size over this 4 GiB bound.

Encode::size_hint()
can be used for sanity checks, but do not assume that the size returned is accurate.
For example, the Json<T> and Text<T> adapters have no reasonable way to predict or estimate the final encoded size,
so they just return size_of::<T>() instead.

For web application backends, consider adding some middleware that limits the size of request bodies by default.

Resolution

sqlx 0.8.1 has been released with the fix: <https://github.com/launchbadge/sqlx/blob/main/CHANGELOG.md#081---2024-08-23>

Postgres users are advised to upgrade ASAP as a possible exploit has been demonstrated:
<launchbadge/sqlx#3440 (comment)>

MySQL and SQLite do not appear to be exploitable, but upgrading is recommended nonetheless.

Warnings

RUSTSEC-2024-0370

proc-macro-error is unmaintained

proc-macro-error's maintainer seems to be unreachable, with no commits for 2 years, no releases pushed for 4 years, and no activity on the GitLab repo or response to email.

proc-macro-error also depends on syn 1.x, which may be bringing duplicate dependencies into dependant build trees.

Possible Alternative(s)

• proc-macro-error2