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curl: fopen race condition: CVE-2023-32001
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From: Daniel Stenberg via curl-users <curl-users_at_lists.haxx.se>
Date: Wed, 19 Jul 2023 08:30:54 +0200 (CEST)
fopen race condition
====================
Project curl Security Advisory, July 19 2023 -
[Permalink](https://curl.se/docs/CVE-2023-32001.html)
VULNERABILITY
-------------
libcurl can be told to save cookie, HSTS and/or alt-svc data to files. When
doing this, it called `stat()` followed by `fopen()` in a way that made it
vulnerable to a TOCTOU race condition problem.
By exploiting this flaw, an attacker could trick the victim to create or
overwrite protected files holding this data in ways it was not intended to.
INFO
Date: Wed, 19 Jul 2023 08:30:54 +0200 (CEST)
fopen race condition
====================
Project curl Security Advisory, July 19 2023 -
[Permalink](https://curl.se/docs/CVE-2023-32001.html)
VULNERABILITY
-------------
libcurl can be told to save cookie, HSTS and/or alt-svc data to files. When
doing this, it called `stat()` followed by `fopen()` in a way that made it
vulnerable to a TOCTOU race condition problem.
By exploiting this flaw, an attacker could trick the victim to create or
overwrite protected files holding this data in ways it was not intended to.
INFO
---- The attacker needs permissions and rights enough to be able to create or rename directory entries in the directory the victim saves their files. This race condition modifies the behavior of symbolic link files in affected components, they might be followed instead of being overwritten when the condition is met leading to undesired and potentially destructive behavior. The Common Vulnerabilities and Exposures (CVE) project has assigned the name CVE-2023-32001 to this issue. CWE-367: Time-of-check Time-of-use (TOCTOU) Race Condition Severity: Medium AFFECTED VERSIONS ----------------- - Affected versions: libcurl 7.84.0 to and including 8.1.2 - Not affected versions: libcurl < 7.84.0 and >= 8.2.0 - Introduced-in: https://github.com/curl/curl/commit/20f9dd6bae50b722 libcurl is used by many applications, but not always advertised as such! SOLUTION ------------ - Fixed-in: https://github.com/curl/curl/commit/0c667188e0c6cda615a0 RECOMMENDATIONS -------------- A - Upgrade curl to version 8.2.0 B - Apply the patch to your local version C - Do not save cookie, HSTS or alt-svc data TIMELINE -------- This issue was reported to the curl project on June 27, 2023. We contacted distros_at_openwall on July 12, 2023. libcurl 8.2.0 was released on July 2023, coordinated with the publication of this advisory. CREDITS ------- - Reported-by: selmelc on hackerone - Patched-by: selmelc on hackerone Thanks a lot! -- / daniel.haxx.se | Commercial curl support up to 24x7 is available! | Private help, bug fixes, support, ports, new features | https://curl.se/support.html -- Unsubscribe: https://lists.haxx.se/mailman/listinfo/curl-users Etiquette: https://curl.se/mail/etiquette.htmlReceived on 2023-07-19