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Unable to generate the correct character set

Critical
fundon published GHSA-9hc7-6w9r-wj94 Jun 4, 2024

Package

cargo nano-id (Rust)

Affected versions

< 0.4.0

Patched versions

0.4.0

Description

Reduced entropy due to inadequate character set usage

Description

Affected versions of the nano-id crate incorrectly generated IDs using a reduced character set in the nano_id::base62 and nano_id::base58 functions. Specifically, the base62 function used a character set of 32 symbols instead of the intended 62 symbols, and the base58 function used a character set of 16 symbols instead of the intended 58 symbols. Additionally, the nano_id::gen macro is also affected when a custom character set that is not a power of 2 in size is specified.

It should be noted that nano_id::base64 is not affected by this vulnerability.

Impact

This can result in a significant reduction in entropy, making the generated IDs predictable and vulnerable to brute-force attacks when the IDs are used in security-sensitive contexts such as session tokens or unique identifiers.

Patches

The flaws were corrected in commit a9022772b2f1ce38929b5b81eccc670ac9d3ab23 by updating the the nano_id::gen macro to use all specified characters correctly.

PoC

use std::collections::BTreeSet;

fn main() {
    test_base58();
    test_base62();
}

fn test_base58() {
    let mut produced_symbols = BTreeSet::new();

    for _ in 0..100_000 {
        let id = nano_id::base58::<10>();
        for c in id.chars() {
            produced_symbols.insert(c);
        }
    }

    println!(
        "{} symbols generated from nano_id::base58",
        produced_symbols.len()
    );
}

fn test_base62() {
    let mut produced_symbols = BTreeSet::new();

    for _ in 0..100_000 {
        let id = nano_id::base62::<10>();
        for c in id.chars() {
            produced_symbols.insert(c);
        }
    }

    println!(
        "{} symbols generated from nano_id::base62",
        produced_symbols.len()
    );
}

Severity

Critical

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
Low

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L

CVE ID

CVE-2024-36400

Weaknesses

Credits