cbcvebase.
CVE-2017-7668
published 2017-06-20

CVE-2017-7668: The HTTP strict parsing changes added in Apache httpd 2.2.32 and 2.4.24 introduced a bug in token list parsing, which allows ap_find_token() to search past the…

PriorityP274high7.5CVSS 3.1
AVNACLPRNUINSUCNINAH
ITWVulnCheck KEV
Exploited in the wild
EPSS
57.47%
99.0th percentile
The HTTP strict parsing changes added in Apache httpd 2.2.32 and 2.4.24 introduced a bug in token list parsing, which allows ap_find_token() to search past the end of its input string. By maliciously crafting a sequence of request headers, an attacker may be able to cause a segmentation fault, or to force ap_find_token() to return an incorrect value.

Affected

34 ranges· showing 25
VendorProductVersion rangeFixed in
apachehttp_server
apachehttp_server
apachehttp_server
apache_software_foundationapache_http_server
apache_software_foundationapache_http_server
applemac_os_x< 10.13.110.13.1
applemac_os_x
applemac_os_x
applemac_os_x>= 10.11.0 < 10.11.610.11.6
applemac_os_x>= 10.12.0 < 10.12.610.12.6
applemacos_high_sierra_10.13.1_security_update_2017-001_sierra_and_security_update_20
debianapache2< apache2 2.4.25-4 (bookworm)apache2 2.4.25-4 (bookworm)
debiandebian_linux
debiandebian_linux
oraclesecure_global_desktop
redhatenterprise_linux_desktop
redhatenterprise_linux_eus
redhatenterprise_linux_eus
redhatenterprise_linux_eus
redhatenterprise_linux_eus
redhatenterprise_linux_eus
redhatenterprise_linux_eus
redhatenterprise_linux_server
redhatenterprise_linux_server_aus
redhatenterprise_linux_server_aus

Detection & IOCsextracted from sources · hover to see the quote

  • Trigger condition: maliciously crafted sequence of request headers causes ap_find_token() to read past end of input string, potentially resulting in a segmentation fault in the httpd child process
  • Vulnerable function is ap_find_token() in Apache httpd; monitor for abnormal httpd child process crashes (segfaults) triggered by HTTP request header sequences
  • Upstream fix commits can be used to diff and derive detection logic: 2.4 fix at apache/httpd commit a585e36e06a53170be6d2d462ceb5b30b8382988; 2.2 fix at commit ad581ced12363ce82ffcb16133f236b2e31563e1
  • ·Only Apache httpd versions 2.2.32 and 2.4.25 are affected; versions prior to the strict HTTP parsing changes (introduced in 2.2.32 / 2.4.24) are NOT vulnerable
  • ·Red Hat Enterprise Linux 5, 6, and associated JBoss products are listed as Not Affected, meaning the strict parsing backport was already corrected in those product lines
  • ·The vulnerability was introduced by the strict HTTP parsing fix for CVE-2016-8743; environments that backported that fix without the subsequent CVE-2017-7668 patch may also be vulnerable regardless of httpd version string
  • ·A vendor-supplied patch for 2.2.32 is available separately; 2.4.25 users must upgrade to 2.4.26

CVSS provenance

nvdv3.17.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
nvdv2.05.0MEDIUMAV:N/AC:L/Au:N/C:N/I:N/A:P
osv9.8CRITICAL
vulncheck7.5HIGH
vendor_ubuntu9.8CRITICAL
vendor_debian7.5HIGH
vendor_redhat7.5HIGH
CVEs like this are exactly what “Exploited This Week” covers.

Every Monday: what got weaponized or added to CISA KEV in the last seven days — each CVE cross-linked to its PoC, Nuclei template, and detection rule. Free, one email a week, unsubscribe in one click.