Broken Rate Limiting Bypasses Second Factor Authentication

The miniOrange 2FA WordPress plugin before 6.3.1, miniOrange 2FA WordPress plugin before 19.3 does not scope its second-factor attempt limit to the account being attacked, keying it instead to an identifier the client supplies and can change at will, allowing an attacker who already knows a victim's password to make unlimited one-time-passcode guesses and defeat the second factor. A second validation endpoint applies no attempt limit at all.

Casky was already ahead

This CVE exploits attack patterns that Casky's 283matched skills already investigate — long before this vulnerability was disclosed. Claude's reasoning model maps these techniques to MITRE ATT&CK, so practitioners who ran these skills have already seen the threat behaviour in their findings.

Analysis

CVE-2026-77771 exploits a critical flaw in the miniOrange 2FA WordPress plugin where rate limiting on one-time-passcode (OTP) attempts is keyed to a client-controlled identifier rather than the targeted account. This means an attacker who has already compromised a user's password can bypass the second factor entirely by making unlimited OTP guesses—essentially reducing multi-factor authentication to single-factor security. A secondary validation endpoint compounds the risk by applying no attempt limits whatsoever. This vulnerability affects WordPress sites relying on miniOrange 2FA for account protection, undermining the trust model that 2FA is supposed to provide. For any organization using affected versions (before 6.3.1 or 19.3), accounts with known or guessed passwords are vulnerable to immediate takeover.

Casky's 283 matching skills detect the attack patterns underlying this vulnerability by analyzing behaviors associated with MITRE ATT&CK techniques TA0004 (Privilege Escalation) and TA0006 (Credential Access). Practitioners using Casky would identify suspicious patterns including: repeated failed authentication attempts originating from a single source but with varying or spoofed client identifiers; abnormally high volumes of OTP validation requests against a single account; and successful authentication following clusters of failed second-factor attempts. Claude's extended reasoning capability helps practitioners correlate these signals to recognize that an attacker is systematically enumerating OTP codes rather than conducting typical brute-force attacks. The skill set also surfaces the architectural weakness—that rate limits tied to client-supplied values are inherently bypassable—allowing teams to audit similar authentication flows in their infrastructure before exploitation occurs.

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Casky Risk Score

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EPSS Probability

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Shodan Exposure

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GreyNoise Signal

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Composite risk scoring from EPSS, CISA KEV, Shodan, and GreyNoise — 21 security APIs correlated into a single Casky Risk Score. Coming in Casky Pro. Join early access →

283 Casky skills cover this attack pattern

These skills use Claude AI's reasoning model to surface findings in the same attack categories as CVE-2026-77771.

abusing-dpapi-for-credential-access

red teaming · high

Run

abusing-shadow-credentials-for-privesc

red teaming · high

Run

Access with Stolen Session Cookie

identity access management · low

Run

MITRE ATT&CK Techniques

TA0004 TA0006

Investigate the attack patterns behind CVE-2026-77771

Casky has 283 skills that investigate the attack patterns behind CVE-2026-77771. Run one and get CVSS-scored findings in 3 minutes.

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