CVE-2021-21373 — Nimble falls back to insecure http url when fetching packages

Nimble is a package manager for the Nim programming language. In Nim release versions before versions 1.2.10 and 1.4.4, "nimble refresh" fetches a list of Nimble packages over HTTPS by default. In case of error it falls back to a non-TLS URL http://irclogs.nim-lang.org/packages.json. An attacker able to perform MitM can deliver a modified package list containing malicious software packages. If the packages are installed and used the attack escalates to untrusted code execution.

Published Mar 26, 2021Updated Aug 3, 2024Sources: cvelistV5, GitHub_M

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the scoring sources call it.

Exploitation

Unreported

no source claims exploitation

EPSS

chance of exploitation in 30 days

Affects

nim lang

security

CVSS base

7.5

HIGH

Affected scope

The catalog records vendors and products as separate lists, not pairs, so which product belongs to which vendor is not something this page can say.

Vendors (1)

nim lang

Products (1)

security

Every base score collected

Sources score independently and disagree; each row says who scored it and under which version.

Score	Version	Severity	Expl.	Impact	Source
7.5	CVSS 3.1	HIGH	—	—	cvelistV5

Weakness & attack patterns

CWE-348

Attack patterns reported against this CVE. The ATT&CK techniques below are inferred from its weakness class.

T1557.002Adversary-in-the-Middle: ARP Cache Poisoning
T1584.002Compromise Infrastructure: DNS Server

Detection

Read off the CVSS vector and the weakness class. Starting points, not rules we have tested.

Search application, proxy, and WAF logs for requests touching //irclogs.nim-lang.org/packages.json.

References

3 on the record

consensys.net/diligence/vulnerabilities/nim-insecure-ssl-tls-defaults-remote-code-execution/
x_refsource_MISC
github.com/nim-lang/nimble/blob/master/changelog.markdown#0130
x_refsource_MISC
github.com/nim-lang/security/security/advisories/GHSA-8w52-r35x-rgp8
x_refsource_CONFIRM

Elsewhere on this site

nim langevery CVE for this vendor
CWE-348other pages naming this weakness

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.