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CVE-2022-49264

Vulnérabilité élevée dans Linux (Linux)

CVSS 7.8 · Élevée
EPSS 0.3%
Linux•Linux•Versions : 5.15.33, <=5.17.*, 2.6.12, 5.18, 0, 4.19.246, <2.6.12, 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, <a8054d3fa5deb84b215d6be1b910a978f3cb840d, <dcd46d897adb70d63e025f175a00a89797d31a43, <27a6f495b63a1804cc71be45911065db7757a98c, <=4.9.*, <=5.10.*, <=4.14.*, <98e0c7c702894987732776736c99b85ade6fba45, 4.9.317, <=5.4.*, <=4.19.*, 5.16.19, <1290eb4412aa0f0e9f3434b406dc8e255da85f9e, <=5.16.*, <1fe82bfd9e4ce93399d815ca458b58505191c3e8, 5.10.110, 5.17.2, <b50fb8dbc8b81aaa126387de428f4c42a7c72a73, <41f6ea5b9aaa28b740d47ffe995a5013211fdbb0, <cfbfff8ce5e3d674947581f1eb9af0a1b1807950, <=5.15.*, <=*, 5.4.197, 4.14.282

Description

In the Linux kernel, the following vulnerability has been resolved: exec: Force single empty string when argv is empty Quoting[1] Ariadne Conill: "In several other operating systems, it is a hard requirement that the second argument to execve(2) be the name of a program, thus prohibiting a scenario where argc < 1. POSIX 2017 also recommends this behaviour, but it is not an explicit requirement[2]: The argument arg0 should point to a filename string that is associated with the process being started by one of the exec functions. ... Interestingly, Michael Kerrisk opened an issue about this in 2008[3], but there was no consensus to support fixing this issue then. Hopefully now that CVE-2021-4034 shows practical exploitative use[4] of this bug in a shellcode, we can reconsider. This issue is being tracked in the KSPP issue tracker[5]." While the initial code searches[6][7] turned up what appeared to be mostly corner case tests, trying to that just reject argv == NULL (or an immediately terminated pointer list) quickly started tripping[8] existing userspace programs. The next best approach is forcing a single empty string into argv and adjusting argc to match. The number of programs depending on argc == 0 seems a smaller set than those calling execve with a NULL argv. Account for the additional stack space in bprm_stack_limits(). Inject an empty string when argc == 0 (and set argc = 1). Warn about the case so userspace has some notice about the change: process './argc0' launched './argc0' with NULL argv: empty string added Additionally WARN() and reject NULL argv usage for kernel threads. [1] https://lore.kernel.org/lkml/20220127000724.15106-1-ariadne@dereferenced.org/ [2] https://pubs.opengroup.org/onlinepubs/9699919799/functions/exec.html [3] https://bugzilla.kernel.org/show_bug.cgi?id=8408 [4] https://www.qualys.com/2022/01/25/cve-2021-4034/pwnkit.txt [5] https://github.com/KSPP/linux/issues/176 [6] https://codesearch.debian.net/search?q=execve%5C+*%5C%28%5B%5E%2C%5D%2B%2C+*NULL&literal=0 [7] https://codesearch.debian.net/search?q=execlp%3F%5Cs*%5C%28%5B%5E%2C%5D%2B%2C%5Cs*NULL&literal=0 [8] https://lore.kernel.org/lkml/20220131144352.GE16385@xsang-OptiPlex-9020/

Gravité et risque d'exploitation

CVE-2022-49264 obtient un score CVSS de 7.8/10, soit une gravité élevée. Selon le modèle EPSS, la probabilité qu'elle soit exploitée dans les 30 prochains jours est de 0.30 %, ce qui la place devant 21.9 % des CVE référencées.

Que faire ?

  • Vérifiez si Linux (versions 5.15.33, <=5.17.*, 2.6.12, 5.18, 0, 4.19.246, <2.6.12, 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, <a8054d3fa5deb84b215d6be1b910a978f3cb840d, <dcd46d897adb70d63e025f175a00a89797d31a43, <27a6f495b63a1804cc71be45911065db7757a98c, <=4.9.*, <=5.10.*, <=4.14.*, <98e0c7c702894987732776736c99b85ade6fba45, 4.9.317, <=5.4.*, <=4.19.*, 5.16.19, <1290eb4412aa0f0e9f3434b406dc8e255da85f9e, <=5.16.*, <1fe82bfd9e4ce93399d815ca458b58505191c3e8, 5.10.110, 5.17.2, <b50fb8dbc8b81aaa126387de428f4c42a7c72a73, <41f6ea5b9aaa28b740d47ffe995a5013211fdbb0, <cfbfff8ce5e3d674947581f1eb9af0a1b1807950, <=5.15.*, <=*, 5.4.197, 4.14.282) est présent sur votre parc.
  • Appliquez le correctif ou la version corrigée indiqués dans les références de l'éditeur.
  • À défaut de correctif, limitez l'exposition (filtrage réseau, désactivation du composant).
  • Automatisez la détection : les agents CVE Heimdall (gratuits, open source) corrèlent l'inventaire de vos serveurs avec la base CVE.

Références

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