CVE-2023-38545: curl SOCKS5 oversized hostname vulnerability.
https://curl.se/docs/CVE-2023-38545.html
Last week, Daniel Stenberg announced that he would release a new
version of the curl library and command line tool today, fixing a
significant vulnerability. Curl is the de-facto standard library to
create HTTP requests unless you still use Perl (good old LWP..). A
significant vulnerability in curl will affect pretty much anything
connecting to a web server. With everything becoming an HTTP-based API,
code using curl is probably written faster than ever, and Daniel's work
is more important than ever.
Today, we got the promised fix for CVE-2023-38545. So here is a quick overview of how severe it is:
The vulnerability is a heap-based buffer overflow, which may lead to
arbitrary code execution. Modern operating systems should make
exploitation of heap-based buffer overflows more difficult, but
exploitation is possible.
To exploit this vulnerability, the attacker has to be able to supply
an oversized hostname to curl. Host names passed to curl should be
validated, and I do not believe such an oversized hostname would pass
input validation. Sure, an attacker can run "curl" on the command line,
but if they can do so, they already have code execution capabilities. A
valid exploit would require an attacker to trigger code execution by,
for example, passing a hostname to a web app that would trigger the code
execution in curl.
Next, the exploit only exists if curl is used to connect to a SOCKS5
proxy. This is another dependency, making exploitation less likely.
October 2023 Microsoft Patch Tuesday Summary
For October, Microsoft released
patches for 105 different vulnerabilities. This count includes one
Chromium vulnerability that was patched earlier this month.
There are a total of three already exploited vulnerabilities:
CVE-2023-44487 HTTP/2 Rapid Reset Attack: This vulnerability was
disclosed by Cloudflare in a blog post earlier today [1]. Cloudflare
started to see these attacks late in August. This issue led to
unprecedented DoS attacks. An attacker will set an HTTP/2 stream and
immediately "cancel" it with a reset stream. This avoids limits on the
number of streams accepted and can lead to CPU exhaustion on the server
attempting to clean up the canceled streams. This is not a TCP RST but
an application layer (HTTP/2) feature. On the other hand, it does look a
bit like a SYN flood attack, maybe? HTTP/2 often appears to
re-implement some of the features found in TCP, so it is no surprise to
see similar vulnerabilities.
CVE-2023-36563 Wordpad Information Disclosure: Yet another problem
with linked resources that may cause the client (Wordpad in this case)
to initiate an SMB connection and in the process, automatically pass
along weakly hashed credentials. See this blog post for details: https://support.microsoft.com/
CVE-2023-41763: Skype for Business elevation of privileges. This is a
vulnerability in the Skype for Business server product. IP addresses and
port numbers may be disclosed.
Noteworthy are the nine critical vulnerabilities in the Layer 2
Tunneling protocol and the vulnerabilities in the Microsoft Message
Queue (one with a CVSS score of 9.8). These two components received
numerous patches for the last couple of months.
Overall, I would rate this patch Tuesday as "average." There are no "outrageously important" vulnerabilities to patch.
Apple fixes vulnerabilities in iOS and iPadOS
Apple 2023-10-04, released iOS/iPadOS 17.0.3. These updates fix two
vulnerabilities. A WebRTC vulnerability that could be used to execute
arbitrary code, establishing initial access to the device, and a Kernel
vulnerability used to elevate privileges. The privilege escalation
vulnerability has been exploited against older versions of iOS. See
Apple's page about these vulnerabilities: https://support.apple.com/en-
