Vulnerability Name:

CVE-2021-42717 (CCN-214484)

Assigned:2021-12-03
Published:2021-12-03
Updated:2022-09-03
Summary:ModSecurity 3.x through 3.0.5 mishandles excessively nested JSON objects. Crafted JSON objects with nesting tens-of-thousands deep could result in the web server being unable to service legitimate requests. Even a moderately large (e.g., 300KB) HTTP request can occupy one of the limited NGINX worker processes for minutes and consume almost all of the available CPU on the machine. Modsecurity 2 is similarly vulnerable: the affected versions include 2.8.0 through 2.9.4.
CVSS v3 Severity:7.5 High (CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)
6.5 Medium (Temporal CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C)
Exploitability Metrics:Attack Vector (AV): Network
Attack Complexity (AC): Low
Privileges Required (PR): None
User Interaction (UI): None
Scope:Scope (S): Unchanged
Impact Metrics:Confidentiality (C): None
Integrity (I): None
Availibility (A): High
5.3 Medium (CCN CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L)
4.6 Medium (CCN Temporal CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L/E:U/RL:O/RC:C)
Exploitability Metrics:Attack Vector (AV): Network
Attack Complexity (AC): Low
Privileges Required (PR): None
User Interaction (UI): None
Scope:Scope (S): Unchanged
Impact Metrics:Confidentiality (C): None
Integrity (I): None
Availibility (A): Low
CVSS v2 Severity:5.0 Medium (CVSS v2 Vector: AV:N/AC:L/Au:N/C:N/I:N/A:P)
Exploitability Metrics:Access Vector (AV): Network
Access Complexity (AC): Low
Authentication (Au): None
Impact Metrics:Confidentiality (C): None
Integrity (I): None
Availibility (A): Partial
5.0 Medium (CCN CVSS v2 Vector: AV:N/AC:L/Au:N/C:N/I:N/A:P)
Exploitability Metrics:Access Vector (AV): Network
Access Complexity (AC): Low
Athentication (Au): None
Impact Metrics:Confidentiality (C): None
Integrity (I): None
Availibility (A): Partial
Vulnerability Type:CWE-674
Vulnerability Consequences:Denial of Service
References:Source: MITRE
Type: CNA
CVE-2021-42717

Source: XF
Type: UNKNOWN
f5-cve202142717-dos(214484)

Source: MLIST
Type: Mailing List, Third Party Advisory
[debian-lts-announce] 20220528 [SECURITY] [DLA 3031-1] modsecurity-apache security update

Source: CCN
Type: F5 Security Advisory K50839343
NGINX ModSecurity WAF vulnerability CVE-2021-42717

Source: DEBIAN
Type: Third Party Advisory
DSA-5023

Source: MISC
Type: Patch, Third Party Advisory
https://www.oracle.com/security-alerts/cpuapr2022.html

Source: MISC
Type: Exploit, Mitigation, Vendor Advisory
https://www.trustwave.com/en-us/resources/blogs/spiderlabs-blog/modsecurity-dos-vulnerability-in-json-parsing-cve-2021-42717/

Vulnerable Configuration:Configuration 1:
  • cpe:/a:trustwave:modsecurity:*:*:*:*:*:*:*:* (Version >= 2.0.0 and < 2.9.5)
  • OR cpe:/a:trustwave:modsecurity:*:*:*:*:*:*:*:* (Version >= 3.0.0 and < 3.0.6)

  • Configuration 2:
  • cpe:/a:f5:nginx_modsecurity_waf:r25:*:*:*:*:*:*:*
  • OR cpe:/a:f5:nginx_modsecurity_waf:r24:*:*:*:*:*:*:*

  • Configuration 3:
  • cpe:/o:debian:debian_linux:9.0:*:*:*:*:*:*:*
  • OR cpe:/o:debian:debian_linux:10.0:*:*:*:*:*:*:*
  • OR cpe:/o:debian:debian_linux:11.0:*:*:*:*:*:*:*

  • Configuration 4:
  • cpe:/a:oracle:http_server:12.2.1.3.0:*:*:*:*:*:*:*
  • OR cpe:/a:oracle:http_server:12.2.1.4.0:*:*:*:*:*:*:*
  • OR cpe:/a:oracle:zfs_storage_appliance_kit:8.8:*:*:*:*:*:*:*

  • * Denotes that component is vulnerable
    BACK
    trustwave modsecurity *
    trustwave modsecurity *
    f5 nginx modsecurity waf r25
    f5 nginx modsecurity waf r24
    debian debian linux 9.0
    debian debian linux 10.0
    debian debian linux 11.0
    oracle http server 12.2.1.3.0
    oracle http server 12.2.1.4.0
    oracle zfs storage appliance kit 8.8