cbcvebase.
CVE-2019-10097
published 2019-09-26

CVE-2019-10097: In Apache HTTP Server 2.4.32-2.4.39, when mod_remoteip was configured to use a trusted intermediary proxy server using the "PROXY" protocol, a specially…

PriorityP279high7.2CVSS 3.1
AVNACLPRHUINSUCHIHAH
ITWVulnCheck KEV
Exploited in the wild
EPSS
52.87%
98.9th percentile
In Apache HTTP Server 2.4.32-2.4.39, when mod_remoteip was configured to use a trusted intermediary proxy server using the "PROXY" protocol, a specially crafted PROXY header could trigger a stack buffer overflow or NULL pointer deference. This vulnerability could only be triggered by a trusted proxy and not by untrusted HTTP clients.

Affected

21 ranges
VendorProductVersion rangeFixed in
apachehttp_server
apachehttp_server
apachehttp_server
apachehttp_server
apachehttp_server
debianapache2< apache2 2.4.41-1 (bookworm)apache2 2.4.41-1 (bookworm)
oraclecommunications_element_manager
oraclecommunications_element_manager
oraclecommunications_element_manager
oraclecommunications_element_manager
oraclecommunications_session_report_manager
oraclecommunications_session_report_manager
oraclecommunications_session_report_manager
oraclecommunications_session_route_manager
oraclecommunications_session_route_manager
oraclecommunications_session_route_manager
oracleenterprise_manager_ops_center
oracleenterprise_manager_ops_center
oraclehttp_server
oracleinstantis_enterprisetrack17.1 – 17.3
oracleretail_xstore_point_of_service

Detection & IOCsextracted from sources · hover to see the quote

commandprintf "PROXY aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa\r\n" | nc localhost 6666
commandprintf "PROXY aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa\r\n" | nc localhost 6666
pathmodules/metadata/mod_remoteip.c
bytes
\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A\x21\x32\x08\x6f\x6f
bytes
\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A\x20\x11\x00\x00
  • Detect oversized PROXY v1 headers: alert on any PROXY protocol v1 line beginning with 'PROXY ' that exceeds 108 bytes (sizeof hdr->v1.line) before the CRLF terminator, as this triggers the strcpy stack overflow in remoteip_process_v1_handler.
  • Detect PROXY v2 LOCAL command (byte 13 = 0x20) sent to httpd listeners with mod_remoteip/RemoteIPProxyProtocol enabled; this triggers a NULL pointer dereference via HDR_DONE returned without populating client_addr.
  • Detect PROXY v2 messages with unsupported address family/protocol (default case in fam switch) sent to httpd; these also return HDR_DONE without populating client_addr, causing a NULL pointer dereference crash.
  • Scan Apache httpd configuration for RemoteIP* directives to identify hosts vulnerable to CVE-2019-10097; the flaw is only exploitable when such directives are present.
  • Monitor for httpd worker thread SIGSEGV crashes (segmentation faults) in mod_remoteip.c around line 1248 (ap_log_cerror APLOGNO 03511), which is the NULL pointer dereference site for the PROXY v2 exploit path.
  • The vulnerability affects only connections from configured trusted proxy IPs; detection should focus on PROXY protocol traffic arriving on the httpd listener port from those trusted intermediary addresses, not from arbitrary HTTP clients.
  • ·CVE-2019-10097 is only exploitable when mod_remoteip is loaded AND RemoteIPProxyProtocol is enabled in the Apache httpd configuration. Instances without these directives are not affected.
  • ·The exploit can only be delivered by a host that is configured as a trusted proxy (via RemoteIPTrustedProxy or equivalent); untrusted HTTP clients cannot trigger this vulnerability.
  • ·Both PROXY protocol version 1 (ASCII) and version 2 (binary) request paths are affected; detection rules must cover both wire formats.
  • ·Red Hat Enterprise Linux 5, 6, and 7 ship httpd versions that are not affected; only RHSCL and JBoss packages in the 2.4.32–2.4.39 range require patching.

CVSS provenance

nvdv3.17.2HIGHCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
nvdv2.06.0MEDIUMAV:N/AC:M/Au:S/C:P/I:P/A:P
osv7.2HIGH
vulncheck7.2HIGH
vendor_debian7.2HIGH
vendor_oracle7.2HIGH
vendor_redhat7.2HIGH
vendor_ubuntu4.2MEDIUM
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.