Security Bulletin: Multiple vulnerabilities in IBM HTTP Server used by IBM WebSphere Application Server due to Expat vulnerabilities

Summary

There are multiple vulnerabilities in the Expat library affecting the IBM HTTP Server used by IBM WebSphere Application Server (CVE-2022-25313, CVE-2022-25315, CVE-2022-25235,CVE-2022-25236). This has been addressed.

Vulnerability Details

CVEID:CVE-2022-25236
**DESCRIPTION:**libexpat is vulnerable to a denial of service, caused by improper protection against insertion of namesep characters into namespace URIs in xmlparse.c. By sending a specially-crafted request, a remote attacker could exploit this vulnerability to cause a denial of service condition.
CVSS Base score: 5.3
CVSS Temporal Score: See: https://exchange.xforce.ibmcloud.com/vulnerabilities/219784 for the current score.
CVSS Vector: (CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L)

CVEID:CVE-2022-25235
**DESCRIPTION:**libexpat is vulnerable to a denial of service, caused by improper input validation in xmltok_impl.c. By persuading a victim to open a specially-crafted content with malformed encoding, a remote attacker could exploit this vulnerability to cause a denial of service condition.
CVSS Base score: 3.3
CVSS Temporal Score: See: https://exchange.xforce.ibmcloud.com/vulnerabilities/219782 for the current score.
CVSS Vector: (CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L)

CVEID:CVE-2022-25313
**DESCRIPTION:**libexpat is vulnerable to a denial of service, caused by stack exhaustion in build_model. By persuading a victim to open a specially-crafted file, a remote attacker could exploit this vulnerability using a large nesting depth in the DTD element to cause a denial of service.
CVSS Base score: 5.5
CVSS Temporal Score: See: https://exchange.xforce.ibmcloud.com/vulnerabilities/219947 for the current score.
CVSS Vector: (CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H)

CVEID:CVE-2022-25315
**DESCRIPTION:**libexpat could allow a remote attacker to execute arbitrary code on the system, caused by an integer overflow in storeRawNames. By persuading a victim to open a specially-crafted file, an attacker could overflow a buffer and execute arbitrary code on the system.
CVSS Base score: 7.8
CVSS Temporal Score: See: https://exchange.xforce.ibmcloud.com/vulnerabilities/219945 for the current score.
CVSS Vector: (CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H)

Affected Products and Versions

This vulnerability affects the following version and release of IBM HTTP Server (powered by Apache) component in all editions of IBM WebSphere Application Server and bundling products.

Remediation/Fixes

IBM strongly recommends addressing the vulnerability now by applying a currently available interim fix or fix pack that contains APAR PH44271.

For IBM HTTP Server used by IBM WebSphere Application Server:

For V9.0.0.0 through 9.0.5.11:
· Upgrade to minimal fix pack levels as required by interim fix and then apply Interim Fix PH44271
--OR–
· Apply Fix Pack 9.0.5.12 or later (targeted availability 2Q2022).

For V8.5.0.0 through 8.5.5.21:
· Upgrade to minimal fix pack levels as required by interim fix and then apply Interim Fix PH44271
--OR–
· Apply Fix Pack 8.5.5.22 or later (targeted availability 3Q2022).

For V8.0.0.0 through 8.0.0.15:
· Upgrade to 8.0.0.15 and then apply Interim Fix PH44271

For V7.0.0.0 through 7.0.0.45:
· Upgrade to 7.0.0.45 and then apply Interim Fix PH44271

Additional interim fixes may be available and linked off the interim fix download page.

_IBM HTTP Server V7.0 and V8.0 are no longer in full support; IBM recommends upgrading to a fixed, supported version/release/platform of the product. _

Important Note

IBM strongly suggests that all System z customers be subscribed to the System z Security Portal to receive the latest critical System z security and
integrity service. If you are not subscribed, see the instructions on the System z Security web site. Security and integrity APARs and associated fixes will
be posted to this portal. IBM suggests reviewing the CVSS scores and applying all security or integrity fixes as soon as possible to minimize any potential
risk.

Workarounds and Mitigations

None