The Wiert Corner – irregular stream of stuff

Jeroen W. Pluimers on .NET, C#, Delphi, databases, and personal interests

  • My badges

    Mastodon

  • Twitter Updates

  • My Flickr Stream

    20140508-Delphi-2007--Project-Options--Cannot-Edit-Application-Title-HelpFile-Icon-Theming20140430-Fiddler-Filter-Actions-Button-Run-Filterset-now20140424-VMware-Fusion-6.0.3.-no-reclaimable
    More Photos

  • Pages

  • All categories

  • Enter your email address to subscribe to this blog and receive notifications of new posts by email.

    Join 1,861 other subscribers

Archive for the ‘TCP’ Category

« Previous Entries
Next Entries »

Reminder to self: re-check the Dotpe API Security Breach — bool.dev

Posted by jpluimers on 2025/03/04

Still public merchant information

Still public merchant information

It looks like some store and merchang APIs were not protected back when [Wayback/Archive] Dotpe API Security Breach — bool.dev was published.

Reminder to self: check their status now as I can’t believe their “human error” got fixed properly.

History (reverse chronological order):

  1. [Wayback/Archive] How DotPe’s ‘Human Error’ Exposed Confidential Customer API Data
  2. [Wayback/Archive] Deedy on X: “Today, Google-backed DotPe locked down their APIs by rate-limiting by IP on /external/merchant and blocking others. They sent a legal notice to the author before fixing it and haven’t publicly acknowledged the issue at all. Companies must be held accountable for poor security.…”

    [Wayback/Archive] Tweet JSON: [Wayback/Archive] GYSlTthakAEoojp.png:orig (2346×1838)

  3. Now protected private API

    Now protected private API

    [Wayback/Archive] Deedy on X: “6 hours later, the API is still very much public! …”

    [Wayback/Archive] Tweet JSON: [Wayback/Archive] GYK38dXbkAEEEs_.jpg:orig (1358×1798)

Read the rest of this entry »

Posted in Communications Development, Development, HTTP, Infosec (Information Security), Internet protocol suite, REST, Software Development, TCP, Web Development | Leave a Comment »

crt.sh allows you to search for the history of TLS certificates for domains (example: *.wiert.me)

Posted by jpluimers on 2024/11/19

I while ago, I bumped into [Wayback/Archive] crt.sh | Certificate Search that allows searching for (the history of) TLS certificates.

One example of what it returns is [Wayback/Archive] crt.sh | wiert.me (for my blog domain and subdomains).

The basic mechanism of crt.sh is to query various Certificate Transparency logs and Certificate revocation list, terms I vaguely knew, but never fully realised the vast usefulness of (including questions like [Wayback/Archive] How does crt.sh becomes aware of certificates that are in no CT logs?).

The cool thing is that most (everything?) of it is open source in the various repositories at [Wayback/Archive] Github: crt.sh.

There is also an advanced search page [Wayback/Archive] crt.sh | Certificate Search (a=1) with many more options (including linting) I really want to try later plus a bunch of background links (including the support forum at) of which some *.crt.sh returned a http 502 while writing this blog post. Will try later to see if they have started working again:

Read the rest of this entry »

Posted in Communications Development, Development, Encryption, HTTPS/TLS security, Internet protocol suite, Power User, Security, TCP, TLS | Leave a Comment »

string – Check if MyString[1] is an alphabetical character? – Stack Overflow (and how Embarcadero broke one of the product version neutral redirects)

Posted by jpluimers on 2024/09/24

Quite a while ago [Wayback/Archive] string – Check if MyString[1] is an alphabetical character? – Stack Overflow asked by [Wayback/Archive] User Jeff was answered by [Wayback/Archive] Andreas Rejbrand:

The simplest approach is

function GetAlphaSubstr(const Str: string): string;
const
  ALPHA_CHARS = ['a'..'z', 'A'..'Z'];
var
  ActualLength: integer;
  i: Integer;
begin
  SetLength(result, length(Str));
  ActualLength := 0;
  for i := 1 to length(Str) do
    if Str[i] in ALPHA_CHARS then
    begin
      inc(ActualLength);
      result[ActualLength] := Str[i];
    end;
  SetLength(Result, ActualLength);
end;

but this will only consider English letters as “alphabetical characters”. It will not even consider the extremely important Swedish letters Å, Ä, and Ö as “alphabetical characters”!

Slightly more sophisticated is

function GetAlphaSubstr2(const Str: string): string;
var
  ActualLength: integer;
  i: Integer;
begin
  SetLength(result, length(Str));
  ActualLength := 0;
  for i := 1 to length(Str) do
    if Character.IsLetter(Str[i]) then
    begin
      inc(ActualLength);
      result[ActualLength] := Str[i];
    end;
  SetLength(Result, ActualLength);
end;

Back in 2011 I added a comment that for more than a decade would redirect to the most current documentation on the IsLetter method:

+1 for using IsLetter which checks the Unicode definition for being a letter or not [Wayback] docwiki.embarcadero.com/VCL/en/Character.TCharacter.IsLetter

Back then, Delphi X2 was current, so it would redirect

  1. from [Wayback] http://docwiki.embarcadero.com/VCL/en/Character.TCharacter.IsLetter
  2. to [Wayback] http://docwiki.embarcadero.com/VCL/XE2/en/Character.TCharacter.IsLetter
  3. then to [Wayback] http://docwiki.embarcadero.com/VCL/XE2/en/Character.TCharacter.IsLetter
  4. ending at [Wayback] http://docwiki.embarcadero.com/Libraries/XE2/en/System.Character.TCharacter.IsLetter

After a long outage in 2022 (see The Delphi documentation site docwiki.embarcadero.com has been down/up oscillating for 4 days is now down for almost a day.) only the Alexandria help was restored.

This killed the above redirect.

Luckily [Wayback/Archive] George Birbilis noticed that and commented this:

@JeroenWiertPluimers the correct link now is: docwiki.embarcadero.com/Libraries/Alexandria/en/…

In order to refer to the most recent Delphi version, now you have to use [Wayback] http://docwiki.embarcadero.com/Libraries/en/System.Character.TCharacter.IsLetter.

This redirects:

  1. via [Wayback] http://docwiki.embarcadero.com/Libraries/Alexandria/en/System.Character.TCharacter.IsLetter to
  2. to [Wayback] https://docwiki.embarcadero.com/Libraries/Alexandria/en/System.Character.TCharacter.IsLetter

The above breaks the help integration from older Delphi products which is bad. It is also bad because it makes it harder to port legacy Delphi code to more modern Delphi versions.

Hopefully the above gives you a bit insight how the docwiki help system was designed and what is left of that design.

–jeroen

Posted in Communications Development, Conference Topics, Conferences, Delphi, Development, Encryption, Event, HTML, HTTP, https, HTTPS/TLS security, Internet protocol suite, Power User, Security, Software Development, TCP, TLS, Web Development | Leave a Comment »

Guess the maximum DNS Response Size… (by Jan Schaumann)

Posted by jpluimers on 2023/12/26

Every once in a while Jan Schaumann writes a long Twitter thread and saves it in a blog post. Always good ways to learn. This time it was no different: [Wayback/Archive] DNS Response Size started with

Read the rest of this entry »

Posted in Communications Development, Development, DNS, Internet, Internet protocol suite, IPv4, IPv6, Power User, TCP, tcpdump, UDP, Wireshark | Leave a Comment »

Some threadreaderapp URLs

Posted by jpluimers on 2023/09/14

For my link archive so I can better automate archiving Tweet threads using bookmarklets written in JavaScript:

The base will likely be this:

javascript:void(open(`https://archive.is/?run=1&url=${encodeURIComponent(document.location)}`))

which for now I have modified into this:

javascript:void(open(`https://threadreaderapp.com/search?q=${document.location}`))

It works perfectly fine without URL encoding and demonstrates the JavaScript backtick feature for template literals for which you can find documentation at [WayBack/Archive] Template literals – JavaScript | MDN.

Read the rest of this entry »

Posted in *nix, *nix-tools, bash, bash, Bookmarklet, Communications Development, cURL, Development, HTTP, https, Internet protocol suite, Power User, Scripting, Security, Software Development, TCP, Web Browsers | Leave a Comment »

5 days after the exploit publication of snowcra5h/CVE-2023-38408: Remote Code Execution in OpenSSH’s forwarded ssh-agent

Posted by jpluimers on 2023/07/26

TL;DR is at the bottom (;

5 days ago this exploit development got published: [Wayback/Archive] snowcra5h/CVE-2023-38408: CVE-2023-38408 Remote Code Execution in OpenSSH’s forwarded ssh-agent.

It is about [Wayback/Archive] NVD – CVE-2023-38408 which there at NIST isn’t rated (yet?), neither at [Wayback/Archive] CVE-2023-38408 : The PKCS#11 feature in ssh-agent in OpenSSH before 9.3p2 has an insufficiently trustworthy search path, leading to remot.

However at [Wayback/Archive] CVE-2023-38408- Red Hat Customer Portal it scores 7.3 and [Wayback/Archive] CVE-2023-38408 | SUSE it did get a rating of 7.5, so since I mainly use OpenSuSE I wondered what to do as the CVE is formulated densely at [Wayback/Archive] www.qualys.com/2023/07/19/cve-2023-38408/rce-openssh-forwarded-ssh-agent.txt: it mentions Alice, but no Bob or Mallory (see Alice and Bob – Wikipedia).

Luckily, others readly already did the fine reading and emphasised the important bits, especially at [Wayback/Archive] RCE Vulnerability in OpenSSH’s SSH-Agent Forwarding: CVE-2023-38408 (note that instead of Alex, they actually mean Alice)

“A system administrator (Alice) runs SSH-agent on her local workstation, connects to a remote server with ssh, and enables SSH-agent forwarding with the -A or ForwardAgent option, thus making her SSH-agent (which is running on her local workstation) reachable from the remote server.”

According to researchers from Qualys, a remote attacker who has control of the host, which Alex has connected to, can load (dlopen()) and immediately unload (dlclose()) any shared library in /usr/lib* on Alice’s workstation (via her forwarded SSH-agent if it is compiled with ENABLE_PKCS11, which is the default).

The vulnerability lies in how SSH-agent handles forwarded shared libraries. When SSH-agent is compiled with ENABLE_PKCS11 (the default configuration), it forwards shared libraries from the user’s local workstation to the remote server. These libraries are loaded (dlopen()) and immediately unloaded (dlclose()) on the user’s workstation. The problem arises because certain shared libraries have side effects when loaded and unloaded, which can be exploited by an attacker who gains access to the remote server where SSH-agent is forwarded to.

Mitigations for the SSH-Agent Forwarding RCE Vulnerability

Read the rest of this entry »

Posted in *nix, *nix-tools, bash, bash, Communications Development, Development, Internet protocol suite, OpenSSH, Power User, PowerShell, Scripting, Security, Software Development, SSH | Leave a Comment »

Looking for maintainer(s) for fritzcap (Python project that captures calls from a Fritz!Box)

Posted by jpluimers on 2023/07/12

Given my health uncertainty, I am looking for maintainers for the fritzcap project (it captures calls from a Fritz!Box modem/router and is written in Python).

History

The fritzcap project was originally started in2007 by [Wayback/Archive] spongebob | IP Phone Forum, first as a binary fritzcap.exe Windows executable (see his first post at [Wayback/Archive] FritzBox: Tool für Etherreal Trace und Audiodaten-Extraktion | IP Phone Forum). In 2010 it became an open source Python project at [Wayback/Archive] Google Code Archive – Long-term storage for Google Code Project Hosting.

Read the rest of this entry »

Posted in About, Audio, Cloud, Communications Development, Containers, Development, Docker, ffmpeg, Fritz!, Fritz!Box, fritzcap, Hardware, HTTP, Infrastructure, Internet protocol suite, Media, Network-and-equipment, Personal, Power User, Python, Scripting, Software Development, TCP | Leave a Comment »

Different ways for installing Windows features on the command line – Peter Hahndorf

Posted by jpluimers on 2023/06/02

If course you can configure Windows Optional Features using the GUI as for instance explained at [Wayback/Archive] How to manage Windows 10’s many ‘optional features | Windows Central.

However, I prefer command-line management.

About the only post doing the comparison of command-line mangement options I could find about is [Wayback/Archive] Different ways for installing Windows features on the command line – Peter Hahndorf and hopefully will be further updated in the future. It is dated 2015, but has been updated until at least Windows Server Nano.

I added one, and then rewrote the tool-set availability table in the post into this:

Read the rest of this entry »

Posted in Communications Development, Development, Internet protocol suite, Microsoft Store, OpenSSH, Power User, SSH, TCP, Windows, Windows 10, Windows 11, Windows 7, Windows 8, Windows 8.1, Windows Server 2008, Windows Server 2008 R2, Windows Server 2012, Windows Server 2012 R2, Windows Server 2016, Windows Vista | Leave a Comment »

Some resources on CORS proxies

Posted by jpluimers on 2023/04/19

Having my background before the web-development era, and having lived mostly in back-ends or client-server front-ends, I sometimes need to really dig into things in order to understand them better.

CORS is such a thing, so below are some links to get started. My main interest is CORS proxies as they will force me do go deep and really get what is going on below the surface.

Defunct CORS proxy sites:

Used searches:

–jeroen

Posted in Communications Development, Development, HTTP, Internet protocol suite, REST, Software Development, TCP, Web Development | Leave a Comment »

Installing Windows OpenSSH from the command-line on Windows 10 and 11

Posted by jpluimers on 2023/03/28

While writing On my reading list: Windows Console and PTY, I found out that OpenSSH had become available as an optional Windows feature.

It was in [Wayback/Archive.is] Windows Command-Line: Introducing the Windows Pseudo Console (ConPTY) | Windows Command Line:

Thankfully, OpenSSH was recently ported to Windows and added as a Windows 10 optional feature. PowerShell Core has also adopted ssh as one of its supported PowerShell Core Remoting protocols.

Here are a few links:

Read the rest of this entry »

Posted in *nix, *nix-tools, Communications Development, ConPTY, Console (command prompt window), Development, Internet protocol suite, OpenSSH, Power User, SSH, ssh/sshd, TCP, Windows, Windows 10, Windows 11 | Leave a Comment »

« Previous Entries
Next Entries »