Amazon Linux AMI update for bash



Risk High
Patch available YES
Number of vulnerabilities 3
CVE-ID CVE-2016-0634
CVE-2016-7543
CVE-2016-9401
CWE-ID CWE-20
CWE-77
CWE-416
Exploitation vector Network
Public exploit N/A
Vulnerable software
 Amazon Linux AMI
Operating systems & Components / Operating system

Vendor Amazon Web Services

Security Bulletin

This security bulletin contains information about 3 vulnerabilities.

1) Improper input validation

EUVDB-ID: #VU13103

Risk: High

CVSSv4.0: 6.3 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber]

CVE-ID: CVE-2016-0634

CWE-ID: CWE-20 - Improper input validation

Exploit availability: No

Description

The vulnerability allows a remote authenticated attacker to execute arbitrary code on the target system.

The vulnerability exists in the expansion of 'h' in the prompt string due to insufficient validation of user-supplied input. A remote attacker can place shell metacharacters in 'hostname' of a machine and execute arbitrary code with elevated privileges.

Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.

Mitigation

Update the affected packages:

i686:
    bash-doc-4.2.46-28.37.amzn1.i686
    bash-4.2.46-28.37.amzn1.i686
    bash-debuginfo-4.2.46-28.37.amzn1.i686

src:
    bash-4.2.46-28.37.amzn1.src

x86_64:
    bash-debuginfo-4.2.46-28.37.amzn1.x86_64
    bash-4.2.46-28.37.amzn1.x86_64
    bash-doc-4.2.46-28.37.amzn1.x86_64

Vulnerable software versions

Amazon Linux AMI: All versions

CPE2.3 External links

https://alas.aws.amazon.com/ALAS-2017-878.html


Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated user via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.

2) Command injection

EUVDB-ID: #VU13104

Risk: Low

CVSSv4.0: 5.9 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2016-7543

CWE-ID: CWE-77 - Command injection

Exploit availability: No

Description

The vulnerability allows a local attacker to execute arbitrary commands on the target system.

The weakness exists due to insufficient validation of user-supplied input. A local attacker can supply specially crafted SHELLOPTS and PS4 environment variables, inject and execute arbitrary commands with root privileges.

Mitigation

Update the affected packages:

i686:
    bash-doc-4.2.46-28.37.amzn1.i686
    bash-4.2.46-28.37.amzn1.i686
    bash-debuginfo-4.2.46-28.37.amzn1.i686

src:
    bash-4.2.46-28.37.amzn1.src

x86_64:
    bash-debuginfo-4.2.46-28.37.amzn1.x86_64
    bash-4.2.46-28.37.amzn1.x86_64
    bash-doc-4.2.46-28.37.amzn1.x86_64

Vulnerable software versions

Amazon Linux AMI: All versions

CPE2.3 External links

https://alas.aws.amazon.com/ALAS-2017-878.html


Q & A

Can this vulnerability be exploited remotely?

No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.

3) Use-after-free

EUVDB-ID: #VU33511

Risk: Low

CVSSv4.0: 4.3 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2016-9401

CWE-ID: CWE-416 - Use After Free

Exploit availability: No

Description

The vulnerability allows a local authenticated user to perform a denial of service (DoS) attack.

popd in bash might allow local users to bypass the restricted shell and cause a use-after-free via a crafted address.

Mitigation

Update the affected packages:

i686:
    bash-doc-4.2.46-28.37.amzn1.i686
    bash-4.2.46-28.37.amzn1.i686
    bash-debuginfo-4.2.46-28.37.amzn1.i686

src:
    bash-4.2.46-28.37.amzn1.src

x86_64:
    bash-debuginfo-4.2.46-28.37.amzn1.x86_64
    bash-4.2.46-28.37.amzn1.x86_64
    bash-doc-4.2.46-28.37.amzn1.x86_64

Vulnerable software versions

Amazon Linux AMI: All versions

CPE2.3 External links

https://alas.aws.amazon.com/ALAS-2017-878.html


Q & A

Can this vulnerability be exploited remotely?

No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.



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