CVE-2025-0693Network attack vector

Username enumeration via login response timing

Published Jan 23, 2025 · Updated Oct 14, 2025

Observable timing discrepancies in AWS Sign-In before January 16, 2025 allow remote attackers to enumerate valid IAM usernames. The IAM user login flow returned authentication-failure responses with measurably different delays depending on whether the submitted username existed. No authentication is required, but repeated login attempts against a chosen AWS account are needed; the disclosed result is username validity only and does not grant access to AWS resources.

CVSS severity6.9
Medium
EPSS probability0.37%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Observable timing discrepancies in AWS Sign-In before January 16, 2025 allow remote attackers to enumerate valid IAM usernames. The IAM user login flow returned authentication-failure responses with measurably different delays depending on whether the submitted username existed. No authentication is required, but repeated login attempts against a chosen AWS account are needed; the disclosed result is username validity only and does not grant access to AWS resources.

The record

CVE
CVE-2025-0693
Published
Jan 23, 2025
Updated
Oct 14, 2025
Vendor
Amazon Web Services
Product
AWS Sign-In
Classifications
CWE-204, CWE-208, T1087.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 23, 2025CVE publishedPublication date reported by the CVE source.
  2. Oct 14, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=N/A

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Amazon Web Services · AWS Sign-Inversion=N/A

Published CVSS scores

5.3Amazon Web ServicesCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
6.9Amazon Web ServicesCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-204Observable Response Discrepancy
CWE-208Observable Timing Discrepancy
T1087.004Cloud Account

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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