Red Hat update for Apache HTTP Server

Published: 2017-06-07 | Updated: 2022-10-06

Risk	Medium
Patch available	YES
Number of vulnerabilities	7
CVE-ID	CVE-2016-0736 CVE-2016-2161 CVE-2016-6304 CVE-2016-7056 CVE-2016-8610 CVE-2016-8740 CVE-2016-8743
CWE-ID	CWE-696 CWE-20 CWE-400 CWE-310 CWE-388 CWE-401
Exploitation vector	Network
Public exploit	Public exploit code for vulnerability #1 is available. Public exploit code for vulnerability #6 is available.
Vulnerable software	Red Hat Enterprise Linux for x86_64 Operating systems & Components / Operating system
Vendor	Red Hat Inc.

Security Bulletin

This security bulletin contains information about 7 vulnerabilities.

1) Padding oracle attack

EUVDB-ID: #VU1800

Risk: Low

CVSSv4.0: 2.1 [CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:P/U:Clear]

CVE-ID: CVE-2016-0736

CWE-ID: CWE-696 - Incorrect Behavior Order

Exploit availability: Yes

Description

The vulnerability allows a remote attacker to obtain potentially sensitive information.

The vulnerability exists due to an error in Apache mod_session_crypto implementation. A remote attacker with ability to intercept traffic can decipher potentially sensitive information or tamper with data.

Successful exploitation may allow an attacker to perform padding oracle attack against vulnerable web server and obtain potentially sensitive information.

Mitigation

Install update from vendor's website.

Vulnerable software versions

Red Hat Enterprise Linux for x86_64: 6

CPE2.3

cpe:2.3:o:red_hat:red_hat_enterprise_linux:6:*:*:*:*:*:*:*

External links

https://access.redhat.com/errata/RHSA-2017:1414

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the local network (LAN).

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) Improper input validation

EUVDB-ID: #VU1886

Risk: Medium

CVSSv4.0: 6.6 [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]

CVE-ID: CVE-2016-2161

CWE-ID: CWE-20 - Improper input validation

Exploit availability: No

Description

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

The vulnerability exists due to input validation error in mod_auth_digest module when parsing malicious HTTP requests. A remote attacker can send a specially crafted HTTP request to affected server and cause server crash.

Successful exploitation of the vulnerability will result in crash of each server instance.

Mitigation

Install update from vendor's website.

Vulnerable software versions

Red Hat Enterprise Linux for x86_64: 6

CPE2.3

cpe:2.3:o:red_hat:red_hat_enterprise_linux:6:*:*:*:*:*:*:*

External links

https://access.redhat.com/errata/RHSA-2017:1414

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.

3) Resource exhaustion

EUVDB-ID: #VU646

Risk: Medium

CVSSv4.0: 6.6 [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]

CVE-ID: CVE-2016-6304

CWE-ID: CWE-400 - Resource exhaustion

Exploit availability: No

Description

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

The vulnerability exists due to improper resource management in OCSP stapling implementation in OpenSSL. A remote attacker can multiple requests with a large OCSP Status Request extension and consume all available memory on the system.

Mitigation

Install update from vendor's website.

Vulnerable software versions

Red Hat Enterprise Linux for x86_64: 6

CPE2.3

cpe:2.3:o:red_hat:red_hat_enterprise_linux:6:*:*:*:*:*:*:*

External links

https://access.redhat.com/errata/RHSA-2017:1414

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.

4) Information disclosure

EUVDB-ID: #VU4133

Risk: Low

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

CVE-ID: CVE-2016-7056

CWE-ID: CWE-310 - Cryptographic Issues

Exploit availability: No

Description

The vulnerability allows a local user obtain potentially sensitive information.

The vulnerability exists due the OpenSSL does not properly set the BN_FLG_CONSTTIME for nonces when signing with the P-256 elliptic curve in ecdsa_sign_setup() function in crypto/ec/ecdsa_ossl.c. A local attacker can conduct a cache-timing attack and recover ECDSA P-256 private keys

Successful exploitation of this vulnerability may allow an attacker to obtain potentially sensitive information.

The vulnerability is discovered in OpenSSL 1.0.1u. Other versions may also be affected.

Mitigation

Install update from vendor's website.

Vulnerable software versions

Red Hat Enterprise Linux for x86_64: 6

CPE2.3

cpe:2.3:o:red_hat:red_hat_enterprise_linux:6:*:*:*:*:*:*:*

External links

https://access.redhat.com/errata/RHSA-2017:1414

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.

5) Denial of service

EUVDB-ID: #VU1083

Risk: Low

CVSSv4.0: 6.6 [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:Clear]

CVE-ID: CVE-2016-8610

CWE-ID: CWE-388 - Error Handling

Exploit availability: No

Description

The vulnerability allows a remote unauthenticated user to exhaust memory on the target system.
The weakness is due to improper handling of certain packets by the ssl3_read_bytes() function in 'ssl/s3_pkt.c.
By sending a flood of SSL3_AL_WARNING alerts during the SSL handshake, a remote attacker can consume excessive CPU resources that may lead to OpenSSL library being unavailable.
Successful exploitation of the vulnerability results in denial of service on the vulnerable system.

Mitigation

Install update from vendor's website.

Vulnerable software versions

Red Hat Enterprise Linux for x86_64: 6

CPE2.3

cpe:2.3:o:red_hat:red_hat_enterprise_linux:6:*:*:*:*:*:*:*

External links

https://access.redhat.com/errata/RHSA-2017:1414

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.

6) Memory leak

EUVDB-ID: #VU1209

Risk: Low

CVSSv4.0: 7.7 [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:P/U:Clear]

CVE-ID: CVE-2016-8740

CWE-ID: CWE-401 - Missing release of memory after effective lifetime

Exploit availability: Yes

Description

The vulnerability allows a remote attacker to cause denial of service.

The vulnerability exists due to improper handling of HTTP/2 headers, when the Protocols configuration includes h2 or h2c. A remote attacker can send a specially crafted HTTP/2 request, containign CONTINUATION frames to vulnerable instance and consume all available memory resources.

Successful exploitation of the vulnerability will result in denial of service (DoS) of affected web server.

Mitigation

Install update from vendor's website.

Vulnerable software versions

Red Hat Enterprise Linux for x86_64: 6

CPE2.3

cpe:2.3:o:red_hat:red_hat_enterprise_linux:6:*:*:*:*:*:*:*

External links

https://access.redhat.com/errata/RHSA-2017:1414

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.

7) Spoofing attack

EUVDB-ID: #VU1961

Risk: Medium

CVSSv4.0: 2.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2016-8743

CWE-ID: CWE-20 - Improper input validation

Exploit availability: No

Description

The vulnerability allows a remote attacker to perform spoofing attack.

The vulnerability exists due to insufficient sanitization of HTTP request, which contain whitespace characters. A remote attacker can send a specially crafted HTTP request, containing CR, FF, VTAB characters followed by CRLF sequence and inject arbitrary data in server response.

Successful exploitation of this vulnerability may result in content spoofing, web cache poisoning and XSS attacks.

Mitigation

Install update from vendor's website.

Vulnerable software versions

Red Hat Enterprise Linux for x86_64: 6

CPE2.3

cpe:2.3:o:red_hat:red_hat_enterprise_linux:6:*:*:*:*:*:*:*

External links

https://access.redhat.com/errata/RHSA-2017:1414

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.