Amazon Linux AMI update for expat



Published: 2021-01-14 | Updated: 2022-01-17
Risk Medium
Patch available YES
Number of vulnerabilities 2
CVE-ID CVE-2018-20843
CVE-2019-15903
CWE-ID CWE-611
CWE-125
Exploitation vector Network
Public exploit Public exploit code for vulnerability #1 is available.
Public exploit code for vulnerability #2 is available.
Vulnerable software
Subscribe 		Amazon Linux AMI
Operating systems & Components / Operating system

Vendor Amazon Web Services

Security Bulletin

This security bulletin contains information about 2 vulnerabilities.

1) XML External Entity injection

EUVDB-ID: #VU18923

Risk: Medium

CVSSv3.1: 6.7 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N/E:P/RL:O/RC:C]

CVE-ID: CVE-2018-20843

CWE-ID: CWE-611 - Improper Restriction of XML External Entity Reference ('XXE')

Exploit availability: Yes

Description

The vulnerability allows a remote attacker to gain access to sensitive information.

The vulnerability exists due to insufficient validation of user-supplied XML input including XML names that contain a large number of colons. A remote attacker can pass a specially crafted XML code to the affected application and view contents of arbitrary files on the system or initiate requests to external systems.

Successful exploitation of the vulnerability may allow an attacker to view contents of arbitrary file on the server or perform network scanning of internal and external infrastructure.

Mitigation

Update the affected packages:

i686:
    expat-2.1.0-12.24.amzn1.i686
    expat-debuginfo-2.1.0-12.24.amzn1.i686
    expat-devel-2.1.0-12.24.amzn1.i686

src:
    expat-2.1.0-12.24.amzn1.src

x86_64:
    expat-debuginfo-2.1.0-12.24.amzn1.x86_64
    expat-devel-2.1.0-12.24.amzn1.x86_64
    expat-2.1.0-12.24.amzn1.x86_64

Vulnerable software versions

Amazon Linux AMI: All versions

External links

http://alas.aws.amazon.com/ALAS-2021-1459.html


Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability. However, proof of concept for this vulnerability is available.

2) Out-of-bounds read

EUVDB-ID: #VU21091

Risk: Medium

CVSSv3.1: 4.9 [CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:L/E:P/RL:O/RC:C]

CVE-ID: CVE-2019-15903

CWE-ID: CWE-125 - Out-of-bounds read

Exploit availability: Yes

Description

The vulnerability allows a remote attacker to gain access to potentially sensitive information or perform denial of service (DoS) attack.

The vulnerability exists due to a boundary error when processing XML documents within the expat library. A remote attacker can create a specially crafted XML file, pass it to the affected application, trigger out-of-bounds read error and read contents of memory on the system or crash the affected application.

Mitigation

Update the affected packages:

i686:
    expat-2.1.0-12.24.amzn1.i686
    expat-debuginfo-2.1.0-12.24.amzn1.i686
    expat-devel-2.1.0-12.24.amzn1.i686

src:
    expat-2.1.0-12.24.amzn1.src

x86_64:
    expat-debuginfo-2.1.0-12.24.amzn1.x86_64
    expat-devel-2.1.0-12.24.amzn1.x86_64
    expat-2.1.0-12.24.amzn1.x86_64

Vulnerable software versions

Amazon Linux AMI: All versions

External links

http://alas.aws.amazon.com/ALAS-2021-1459.html


Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability. However, proof of concept for this vulnerability is available.



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