Cyber Resilience

CVE-2021-34548

HighPublic PoC

Published: 29 June 2021

Published
29 June 2021
Modified
21 November 2024
KEV Added
Patch
CVSS Score v3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS Score 0.0016 36.6th percentile
Risk Priority 15 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2021-34548 is a high-severity Authentication Bypass by Spoofing (CWE-290) vulnerability in Torproject Tor. Its CVSS base score is 7.5 (High).

Operationally, ranked at the 36.6th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

EU & UK References

Vulnerability details

An issue was discovered in Tor before 0.4.6.5, aka TROVE-2021-003. An attacker can forge RELAY_END or RELAY_RESOLVED to bypass the intended access control for ending a stream.

CWE(s)

Related Threats

No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.

Affected Assets

torproject
tor
≤ 0.3.5.15 · 0.4.0.0 — 0.4.4.9 · 0.4.5.0 — 0.4.5.9

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-290

Reveals spoofed logon attempts through unexpected previous logon timestamps upon legitimate login.

addresses: CWE-290

Training specifically addresses recognizing spoofed communications and phishing that enable authentication bypass.

addresses: CWE-290

Requiring verifiable identity evidence at appropriate assurance levels makes it substantially harder for attackers to successfully spoof or impersonate users to obtain accounts.

addresses: CWE-290

Unique device authentication makes successful spoofing of device identity substantially more difficult to achieve.

addresses: CWE-290

Unique identification of non-organizational users reduces the feasibility of authentication bypass by spoofing.

addresses: CWE-290

Unique identification and authentication of services before communications makes spoofing of service identities substantially harder.

addresses: CWE-290

Isolated trusted path ensures the user interacts only with genuine system components, preventing spoofing of authentication interfaces or prompts.

addresses: CWE-290

Directly counters DNS response spoofing by requiring cryptographic origin authentication artifacts from the authoritative source.

References