SB2019090202 - Ubuntu update for Apache HTTP Server



SB2019090202 - Ubuntu update for Apache HTTP Server

Published: September 2, 2019

Security Bulletin ID SB2019090202
CSH Severity
Medium
Patch available
YES
Number of vulnerabilities 7
Exploitation vector Remote access
Highest impact Denial of service

Breakdown by Severity

Medium 71% Low 29%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 7 vulnerabilities.


1) Resource management error (CVE-ID: CVE-2019-0197)

CWE-ID: CWE-399 - Resource Management Errors

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green


The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to an error within the mod_http2 module when processing update requests from http/1.1 to http/2, if this was not the first request on a connection. A remote attacker can send specially crafted requests to the affected server and perform denial of service attack.

Successful exploitation of the vulnerability requires that HTTP/2 protocol is enabled for a "http:" host or H2Upgrade is enabled for h2 on a "https:" host.


2) Out-of-bounds write (CVE-ID: CVE-2019-10081)

CWE-ID: CWE-787 - Out-of-bounds write

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green


The vulnerability allows a remote attacker to perform denial of service attack.

The vulnerability exists due to a boundary error when processing HTTP/2 requests within the mod_http2 module, configured with "H2PushResource". A remote attacker can send specially crafted HTTP/2 requests to the affected server and perform denial of service (DoS) attack.


3) Use-after-free (CVE-ID: CVE-2019-10082)

CWE-ID: CWE-416 - Use After Free

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U/U:Green


The vulnerability allows a remote attacker to perform denial of service (DoS) attack.

The vulnerability exists due to a use-after-free error within the mod_http2 when handling connection shutdown. A remote attacker can send specially crafted requests to the affected server and make the mod_http2 to read memory that was already freed.



4) Cross-site scripting (CVE-ID: CVE-2019-10092)

CWE-ID: CWE-79 - Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:U/U:Clear


The disclosed vulnerability allows a remote attacker to perform cross-site scripting (XSS) attacks.

The vulnerability exists due to insufficient sanitization of user-supplied data on the mod_proxy error page. A remote attacker can trick the victim to follow a specially crafted link and execute arbitrary HTML and script code in user's browser in context of vulnerable website.

Successful exploitation of this vulnerability may allow a remote attacker to steal potentially sensitive information, change appearance of the web page, perform phishing and drive-by-download attacks.


5) NULL pointer dereference (CVE-ID: CVE-2019-10097)

CWE-ID: CWE-476 - NULL Pointer Dereference

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U/U:Clear


The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to a NULL pointer dereference error when processing PROXY header within the mod_remoteip. A remote attacker that controls a trusted proxy server can send a specially crafted PROXY header,  trigger stack overflow and perform a denial of service (DoS) attack.


6) Input validation error (CVE-ID: CVE-2019-10098)

CWE-ID: CWE-20 - Improper input validation

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:P/U:Green


The vulnerability allows a remote attacker to bypass certain security restrictions.

The vulnerability exists due to incorrect handling of encoded line break characters  within rewrite rules. A remote attacker can send a specially crafted HTTP request and potentially bypass security restrictions.


7) Resource management error (CVE-ID: CVE-2019-9517)

CWE-ID: CWE-399 - Resource Management Errors

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green


The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to incorrect implementation of HTTP/2 protocol. A remote attacker can  open the HTTP/2 window so the peer can send without constraint; however, they leave the TCP window closed so the peer cannot actually write (many of) the bytes on the wire. The attacker then sends a stream of requests for a large response object. Depending on how the servers queue the responses, this can consume excess memory, CPU, or both.

Remediation

Install update from vendor's website.