Covered by FixVibehigh

ZXCVVAKATAWASEWASEGI0. ZXCVVIBETOKEN0ZXCV Veitaqomaki: Na ririko ni tokeni sega ni vakadeitaki kei na yali ni veivakadeitaki ni kerekere ZXCVVAKATAWASEWASEI ZXCVVAKATAWASEWASE1 Na kena vakayacori na JWT sega ni dodonu, me vaka na kena ciqomi na 'sega ni' algorithm se sega ni vakadeitaka na 'exp' kei na 'aud' na veibeitaki, e rawa ni vakavuna na bypass ni veivakadeitaki. ZXCVVAKATAWASEWASEI ZXCVVAKATAWASEWASE2. JSON itukutuku ni ivakatakilakila (JWTs) e vakarautaka e dua na ivakatagedegede ni kena vakadewataki na kerekere, ia na veitaqomaki e vakararavi ena veivakadeitaki kaukauwa. Na sega ni vakadeitaki ni saini, gauna ni vakaoti gauna, se na vakarorogo e nanumi e rawa kina vei ira na dauvakacaca me ra bypass na veivakadeitaki se replay na tokeni. ZXCVVAKATAWASEWASEI ZXCVVAKATAWASEWASE3. ## Na veivakacacani ni veivakacacani ZXCVVAKATAWASEWASEI ZXCVVAKATAWASEWASE4. Na vakadeitaki cala ni ZXCVFIXVIBETOKEN4ZXCV e rawa kina vei ira na dauvakacaca me ra vakawalena na iwalewale ni veivakadeitaki ena nodra vakacala na veibeitaki se vakayagataka tale na ivakatakilakila sa oti na kena gauna. Kevaka e dua na dauveiqaravi e ciqoma na ivakatakilakila ka sega na kena saini dodonu, e dua na dauvakacaca e rawa ni veisautaka na payload me vakalevutaka na dodonu se vakatotomuria e dua na vakayagataki ZXCVFIXVIBETOKEN2ZXCV. Kuria, sega ni vakayacora na kena vakaoti (JWT) kerekere e vakatara e dua na dauvakacaca me vakayagataka e dua na ivakatakilakila vakacacani tawamudu ZXCVFIXVIBETOKEN3ZXCV. ZXCVVAKATAWASEWASEI ZXCVVAKATAWASEGA5. ## Vuna ZXCVVAKATAWASEWASEI ZXCVVAKAVUVULI6. Na ivakatakilakila ni itukutuku ni JSON (ZXCVFIXVIBETOKEN1ZXCV) e dua na ituvatuva yavutaki ena JSON e vakayagataki me matataka na veibeitaki e sainitaki vakadijitali se taqomaki na yalodina JWT. Na leqa ni veitaqomaki e dau vu mai na rua na gaps ni kena vakayacori taumada: ZXCVVAKATAWASEWASEI ZXCVVAKATAWASEWASE77. 1. Ciqomi ni JWTs sega ni vakadeitaki : Kevaka e dua na veiqaravi e sega ni vakabibitaka vakabibi na veivakadeitaki ni saini, e rawa ni vakayacora na "JWTs sega ni vakadeitaki" ena vanua e sega ni tiko kina na saini ka sa vakarautaki na algorithm ki na "sega ni dua" JWT. Ena ituvaki oqo, na dauveiqaravi e vakabauta na veibeitaki ena payload ka sega ni vakadeitaka na nodra yalodina ZXCVFIXVIBETOKEN1ZXCV. ZXCVVAKATAWASEWASEI ZXCVVAKATAWASEWASEG8. 2. Vakadeitaki ni kerekere e yali: Na kerekere ni JWT (gauna ni oti) e vakaraitaka na gauna ena se ni oti na kena sega ni dodonu me ciqomi na ZXCVFIXVIBETOKEN5ZXCV me baleta na kena vakayacori na ZXCVFIXVIBETOKEN2ZXCV. Na ZXCVFIXVIBETOKEN1ZXCV (vakarorogo) kerekere e vakatakilakilataka na vakasamataki ni ciqomi ni ivakatakilakila ZXCVFIXVIBETOKEN3ZXCV. Kevaka era sega ni vakadeitaki oqo, na dauveiqaravi e rawa ni ciqoma na tokeni sa oti na kena gauna se a vakarautaki me baleta e dua na kerekere duidui ZXCVFIXVIBETOKEN4ZXCV. ZXCVVAKATAWASEWASEI ZXCVVAKATAWASEWASE9. ## Vakavinakataki ni simede ZXCVVAKATAWASEWASEI ZXCVVAKATAWASEWASEI10 1. Vakaukauwataka na saini ni Cryptographic: Vakarautaka na kerekere me cakitaka e dua na JWT e sega ni vakayagataka e dua na vakadonui taumada, kaukauwa ni saini ni algorithm (me vaka na RS256). ZXCVVAKATAWASEWASEI ZXCVVAKATAWASEWASEI11 2. Vakadeitaka na Expiration: Vakayacora e dua na jeke vakalawa me vakadeitaka na siga kei na gauna ni gauna oqo e ni bera na gauna e vakaraitaki ena JWT kerekere ZXCVFIXVIBETOKEN1ZXCV. ZXCVVAKATAWASEWASEI ZXCVVAKATAWASEWASEI12 3. Vakadeitaka na vakarorogo: Vakadeitaka na kerekere ni JWT e tiko kina e dua na isau e vakatakilakilataka na veiqaravi ni vanua; kevaka e sega ni vakatakilai na veiqaravi ena kerekere ni ZXCVFIXVIBETOKEN1ZXCV, na ivakatakilakila e dodonu me vakasukai ZXCVFIXVIBETOKEN2ZXCV. ZXCVVAKATAWASEWASEI ZXCVVAKATAWASEWASEI13 4. Tarova na vakatagitaki tale : Vakayagataka na JWT (ZXCVFIXVIBETOKEN2ZXCV ID) kerekere me lesi e dua na ivakatakilakila duatani ki na ivakatakilakila yadua, ka vakatara na dauveiqaravi me vakamuria ka cakitaka na ivakatakilakila vakayagataki tale ZXCVFIXVIBETOKEN1ZXCV. ZXCVVAKATAWASEWASEI ZXCVVAKATAWASEWASEI14 ## Na iwalewale ni kena kunei ZXCVVAKATAWASEWASEI ZXCVVAKATAWASEWASEI15 Na malumalumu ena JWT qaravi e rawa ni kilai ena kena vakadikevi na ituvatuva ni ivakatakilakila kei na itovo ni isau ni dauveiqaravi: ZXCVVAKATAWASEWASEI ZXCVVAKATAWASEWASEI16 * Vakadikevi ni ulutaga: Vakadikeva na ulutaga ni JWT (algorithm) me vakadeitaka ni sa sega ni vakarautaki ki na "sega ni dua" ka vakayagataka na ivakatagedegede ni cryptographic namaki ZXCVFIXVIBETOKEN1ZXCV. ZXCVVAKATAWASEWASEI ZXCVVAKATAWASEWASEI17 * Vakadeitaki ni kerekere: Vakadeitaka na kena tiko kei na kena dina na JWT (oti) kei na ZXCVFIXVIBETOKEN1ZXCV (vakarorogo) kerekere ena loma ni JSON payload ZXCVFIXVIBETOKEN2ZXCV. ZXCVVAKATAWASEWASEI ZXCVVAKATAWASEWASEI18 * Vakatovotovo ni veivakadeitaki: Vakatovolei kevaka e vakadodonutaka na dauveiqaravi na tokeni sa oti na kena gauna me vaka na JWT kerekere se sa vakarautaki me baleta e dua na vakarorogo duidui me vaka e vakamacalataki ena ZXCVFIXVIBETOKEN2XCV kerekere.

JSON Web Tokens (JWTs) provide a standard for transferring claims, but security relies on rigorous validation. Failure to verify signatures, expiration times, or intended audiences allows attackers to bypass authentication or replay tokens.

CWE-347CWE-287CWE-613

Attacker Impact

Improper JWT validation allows attackers to bypass authentication mechanisms by forging claims or reusing expired tokens [S1]. If a server accepts tokens without a valid signature, an attacker can modify the payload to escalate privileges or impersonate any user [S1]. Furthermore, failing to enforce the expiration (exp) claim allows an attacker to use a compromised token indefinitely [S1].

Root Cause

A JSON Web Token (JWT) is a JSON-based structure used to represent claims that are digitally signed or integrity protected [S1]. Security failures typically stem from two primary implementation gaps:

Acceptance of Unsecured JWTs: If a service does not strictly enforce signature verification, it may process "Unsecured JWTs" where the signature is absent and the algorithm is set to "none" [S1]. In this scenario, the server trusts the claims in the payload without verifying their integrity [S1].
Missing Claim Validation: The exp (expiration time) claim identifies the time on or after which the JWT must not be accepted for processing [S1]. The aud (audience) claim identifies the intended recipients of the token [S1]. If these are not checked, the server may accept tokens that are expired or were intended for a different application [S1].

Concrete Fixes

Enforce Cryptographic Signatures: Configure the application to reject any JWT that does not use a pre-approved, strong signing algorithm (such as RS256).
Validate Expiration: Implement a mandatory check to ensure the current date and time are before the time specified in the exp claim [S1].
Verify Audience: Ensure the aud claim contains a value identifying the local service; if the service is not identified in the aud claim, the token must be rejected [S1].
Prevent Replay: Use the jti (JWT ID) claim to assign a unique identifier to each token, allowing the server to track and reject reused tokens [S1].

Detection Strategy

Vulnerabilities in JWT handling can be identified by analyzing the token structure and server response behavior:

Header Inspection: Checking the alg (algorithm) header to ensure it is not set to "none" and uses expected cryptographic standards [S1].
Claim Verification: Confirming the presence and validity of the exp (expiration) and aud (audience) claims within the JSON payload [S1].
Validation Testing: Testing if the server correctly rejects tokens that have expired according to the exp claim or are intended for a different audience as defined by the aud claim [S1].