Tenable.sc update for Apache HTTP Server



Published: 2021-10-19
Risk High
Patch available YES
Number of vulnerabilities 3
CVE-ID CVE-2021-33193
CVE-2021-34798
CVE-2021-40438
CWE-ID CWE-444
CWE-476
CWE-918
Exploitation vector Network
Public exploit Public exploit code for vulnerability #3 is available.
Vulnerable software
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Tenable.sc
Server applications / DLP, anti-spam, sniffers

Vendor Tenable Network Security

Security Bulletin

This security bulletin contains information about 3 vulnerabilities.

1) Inconsistent interpretation of HTTP requests

EUVDB-ID: #VU56474

Risk: Medium

CVSSv3.1: 6.3 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-33193

CWE-ID: CWE-444 - Inconsistent Interpretation of HTTP Requests ('HTTP Request Smuggling')

Exploit availability: No

Description

The vulnerability allows a remote attacker to preform HTTP/2 request smuggling attacks.

The vulnerability exists due to improper validation of HTTP/2 requests in mod_proxy in Apache HTTP Server. A remote attacker can send a specially crafted HTTP/2 request to the server and smuggle arbitrary HTTP headers.

Successful exploitation of vulnerability may allow an attacker to poison web server cache and perform phishing attacks.

Mitigation

Install update from vendor's website.

Vulnerable software versions

Tenable.sc: 5.16.0, 5.17.0, 5.18.0, 5.19.0, 5.19.1

CPE2.3 External links

http://www.tenable.com/security/tns-2021-17

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.

2) NULL pointer dereference

EUVDB-ID: #VU56681

Risk: Medium

CVSSv3.1: 6.5 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-34798

CWE-ID: CWE-476 - NULL Pointer Dereference

Exploit availability: No

Description

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

The vulnerability exists due to a NULL pointer dereference error. A remote attacker can send a specially crafted HTTP request to the affected web server and perform a denial of service (DoS) attack.

Mitigation

Install update from vendor's website.

Vulnerable software versions

Tenable.sc: 5.16.0, 5.17.0, 5.18.0, 5.19.0, 5.19.1

CPE2.3 External links

http://www.tenable.com/security/tns-2021-17

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) Server-Side Request Forgery (SSRF)

EUVDB-ID: #VU56678

Risk: High

CVSSv3.1: 8.4 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:L/A:N/E:P/RL:O/RC:C]

CVE-ID: CVE-2021-40438

CWE-ID: CWE-918 - Server-Side Request Forgery (SSRF)

Exploit availability: Yes

Description

The disclosed vulnerability allows a remote attacker to perform SSRF attacks.

The vulnerability exists due to insufficient validation of user-supplied input within the mod_proxy module in Apache HTTP Server. A remote attacker can send a specially crafted HTTP request with a chosen uri-path and trick the web server to initiate requests to arbitrary systems.

Successful exploitation of this vulnerability may allow a remote attacker gain access to sensitive data, located in the local network or send malicious requests to other servers from the vulnerable system.

Mitigation

Install update from vendor's website.

Vulnerable software versions

Tenable.sc: 5.16.0, 5.17.0, 5.18.0, 5.19.0, 5.19.1

CPE2.3 External links

http://www.tenable.com/security/tns-2021-17

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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