Rapid Reset Attack via HTTP/2 in Microsoft IIS

1) Resource exhaustion

EUVDB-ID: #VU81728

Risk: High

CVSSv4.0: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:A/U:Amber]

CVE-ID: CVE-2023-44487

CWE-ID: CWE-400 - Resource exhaustion

Exploit availability: Yes

Description

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

The vulnerability exists due to improperly control of consumption for internal resources when handling HTTP/2 requests with compressed HEADERS frames. A remote attacker can send a sequence of compressed HEADERS frames followed by RST_STREAM frames and perform a denial of service (DoS) attack, a.k.a. "Rapid Reset".

Note, the vulnerability is being actively exploited in the wild.

Mitigation

Install updates from Microsoft website.

Vulnerable software versions

Windows: 10 - 11 22H2 10.0.22621.521

Windows Server: 2016 10.0.14393.10 - 2022 20H2

Microsoft IIS: 10.0

CPE2.3

• cpe:2.3:o:microsoft:windows:*:*:*:*:*:*:*:*
• cpe:2.3:o:microsoft:windows:10:Mobile:*:*:*:*:*:*
• cpe:2.3:o:microsoft:windows:10_20H2:10.0.19042.572:*:*:*:*:*:*
• cpe:2.3:o:microsoft:windows:10_21H1:10.0.19043.985:*:*:*:*:*:*
• cpe:2.3:o:microsoft:windows:10_21H2:10.0.19044.1288:*:*:*:*:*:*
• cpe:2.3:o:microsoft:windows:10_22H2:10.0.19045.2130:*:*:*:*:*:*
• cpe:2.3:o:microsoft:windows:10_1507:10.0.10240.16405:*:*:*:*:*:*
• cpe:2.3:o:microsoft:windows:10_1703:10.0.15063.138:*:*:*:*:*:*
• cpe:2.3:o:microsoft:windows_server:2016:10.0.14393.10:*:*:*:*:*:*
• cpe:2.3:a:microsoft:microsoft_iis:10.0:*:*:*:*:*:*:*

External links

https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2023-44487

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?

Yes. This vulnerability is being exploited in the wild.