CVE-2019-12520
squid: Improper input validation in request allows for proxy manipulation
Severity Score
Exploit Likelihood
Affected Versions
Public Exploits
0Exploited in Wild
-Decision
Descriptions
An issue was discovered in Squid through 4.7 and 5. When receiving a request, Squid checks its cache to see if it can serve up a response. It does this by making a MD5 hash of the absolute URL of the request. If found, it servers the request. The absolute URL can include the decoded UserInfo (username and password) for certain protocols. This decoded info is prepended to the domain. This allows an attacker to provide a username that has special characters to delimit the domain, and treat the rest of the URL as a path or query string. An attacker could first make a request to their domain using an encoded username, then when a request for the target domain comes in that decodes to the exact URL, it will serve the attacker's HTML instead of the real HTML. On Squid servers that also act as reverse proxies, this allows an attacker to gain access to features that only reverse proxies can use, such as ESI.
Se descubrió un problema en Squid versiones hasta 4.7 y 5. Cuando se recibe una petición, Squid comprueba su memoria caché para visualizar si puede servir una respuesta. Lo hace al realizar un hash MD5 de la URL absoluta de la petición. Si se encuentra, sirve la petición. La URL absoluta puede incluir la UserInfo decodificada (nombre de usuario y contraseña) para determinados protocolos. Esta información decodificada se antepone al dominio. Esto permite a un atacante proporcionar un nombre de usuario que tenga caracteres especiales para delimitar el dominio y tratar el resto de la URL como una ruta o cadena de consulta. Un atacante podría primero hacer una petición a su dominio usando un nombre de usuario codificado, luego, cuando llega una petición para el dominio objetivo que decodifica a la URL exacta, servirá el HTML del atacante en lugar del HTML real. En los servidores de Squid que también actúan como proxies inversos, esto permite a un atacante conseguir acceso a funcionalidades que solo los proxies inversos pueden utilizar, tal y como ESI.
A flaw was found in squid. The absolute URL of a request can include the decoded UserInfo (username and password) for certain protocols. This decoded info may contain special characters to delimit the domain, and treat the rest of the URL as a path or query string. An attacker could first make a request to their domain using an encoded username, then when a request for the target domain comes in that decodes to the exact URL, it will serve the attacker's HTML instead of the real HTML. On Squid servers that also act as reverse proxies, this allows an attacker to gain access to features that only reverse proxies can use, such as ESI.
CVSS Scores
SSVC
- Decision:-
Timeline
- 2019-06-02 CVE Reserved
- 2020-04-15 CVE Published
- 2024-08-04 CVE Updated
- 2024-08-09 EPSS Updated
- ---------- Exploited in Wild
- ---------- KEV Due Date
- ---------- First Exploit
CWE
- CWE-20: Improper Input Validation
CAPEC
References (10)
URL | Tag | Source |
---|---|---|
https://gitlab.com/jeriko.one/security/-/blob/master/squid/CVEs/CVE-2019-12520.txt | Third Party Advisory | |
https://lists.debian.org/debian-lts-announce/2020/07/msg00009.html | Mailing List | |
https://security.netapp.com/advisory/ntap-20210205-0006 | Third Party Advisory |
URL | Date | SRC |
---|
URL | Date | SRC |
---|---|---|
https://github.com/squid-cache/squid/commits/v4 | 2021-02-11 |
URL | Date | SRC |
---|---|---|
http://www.squid-cache.org/Versions/v4 | 2021-02-11 | |
http://www.squid-cache.org/Versions/v4/changesets | 2021-02-11 | |
https://usn.ubuntu.com/4446-1 | 2021-02-11 | |
https://www.debian.org/security/2020/dsa-4682 | 2021-02-11 | |
https://access.redhat.com/security/cve/CVE-2019-12520 | 2020-11-04 | |
https://bugzilla.redhat.com/show_bug.cgi?id=1827558 | 2020-11-04 |
Affected Vendors, Products, and Versions
Vendor | Product | Version | Other | Status | ||||||
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Vendor | Product | Version | Other | Status | <-- --> | Vendor | Product | Version | Other | Status |
Squid-cache Search vendor "Squid-cache" | Squid Search vendor "Squid-cache" for product "Squid" | <= 4.7 Search vendor "Squid-cache" for product "Squid" and version " <= 4.7" | - |
Affected
| ||||||
Canonical Search vendor "Canonical" | Ubuntu Linux Search vendor "Canonical" for product "Ubuntu Linux" | 16.04 Search vendor "Canonical" for product "Ubuntu Linux" and version "16.04" | lts |
Affected
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Canonical Search vendor "Canonical" | Ubuntu Linux Search vendor "Canonical" for product "Ubuntu Linux" | 18.04 Search vendor "Canonical" for product "Ubuntu Linux" and version "18.04" | lts |
Affected
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Debian Search vendor "Debian" | Debian Linux Search vendor "Debian" for product "Debian Linux" | 9.0 Search vendor "Debian" for product "Debian Linux" and version "9.0" | - |
Affected
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Debian Search vendor "Debian" | Debian Linux Search vendor "Debian" for product "Debian Linux" | 10.0 Search vendor "Debian" for product "Debian Linux" and version "10.0" | - |
Affected
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