Archive for the ‘Communications Development’ Category
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:
Back then, Delphi X2 was current, so it would redirect
- from http://docwiki.embarcadero.com/VCL/en/Character.TCharacter.IsLetter
- to [Wayback] http://docwiki.embarcadero.com/VCL/XE2/en/Character.TCharacter.IsLetter
- then to [Wayback] http://docwiki.embarcadero.com/VCL/XE2/en/Character.TCharacter.IsLetter
- 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:
- via [Wayback] http://docwiki.embarcadero.com/Libraries/Alexandria/en/System.Character.TCharacter.IsLetter to
- 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 »
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 »
Posted by jpluimers on 2023/12/24
Jan Wildeboer was mad for good reasons, though the open source projects didn’t yet seem to publicly have show their real madness, just bits like [Wayback/Archive] oss-security – Re: Re: New SMTP smuggling attack:
I'm a little confused by sec-consult's process here. They identify a
problem affecting various pieces of software including some very widely
deployed open source software, go to the trouble of doing a coordinated
disclosure, but only do that with...looking at their timeline... gmx,
microsoft and cisco?
“SMTP Smuggling” is bad, and big open source SMTP server projects like exim, postfix and sendmail needed to assess and fix/prevent the issue on very short notice: effectively confronting them with a zero-day less than a week between the information got released and the Holiday season.
That gives “deploy on Fridays” a totally different dimension.
How bad? Well, it already managed to reach this Newline – Wikipedia entry:
The standard Internet Message Format[26] for email states: “CR and LF MUST only occur together as CRLF; they MUST NOT appear independently in the body”. Differences between SMTP implementations in how they treat bare LF and/or bare CF characters have led to so-called SMTP smuggling attacks[27].
The crux of the problem is very well described by the “Postfix: SMTP Smuggling” link below: recommended reading, and the middle of [Wayback/Archive] SMTP Smuggling – Spoofing Emails Worldwide | Hacker News
…
TLDR: In the SMTP protocol, the end of the payload (email message) is indicated by a line consisting of a single dot. The line endings normally have to be CRLF, but some MTAs also accept just LF before and/or after the dot. This allows SMTP commands that follow an LF-delimited dot line to be “tunneled” through a first MTA (which requires CRLF and thus considers the commands to be part of the email message) to a second MTA (which accepts LF and thus processes the commands as real commands). For the second MTA, the commands appear to come from the first MTA, hence this allows sending any email that the first MTA is authorized to send. That is, emails from arbitrary senders under the domains associated with the first MTA can be spoofed.
…
Here are some links to keep you busy the next hours/days/weeks:
And the toots linking to background information:
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Posted in *nix, *nix-tools, Communications Development, Development, exim mail, Internet protocol suite, postfix, Power User, Python, Scripting, sendmail, SMTP, Software Development | Leave a Comment »
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 »
Posted by jpluimers on 2023/08/25
For my link archive: [Wayback/Archive] Email Handling and vBulletin Cloud – vBulletin Community Forum.
- Asking your end users to white list your email address and the Sendgrid IP (
167.89.58.99) can help alleviate the issues.
I didn’t know the above but bumped into an issue because I didn’t know a supplier had moved to vBulletin Cloud, my account password stopped being accepted and my account password reset messages would not arrive.
So I wrote this as part of a mail to sort this out, and it was confirmed to be correct:
Then I re-checked a few connection refusals that appeared close to the password reset tries. Not sure if this a pattern, but a few of them had this:
167.89.58.99 listed in bl.spamcop.net (127.0.0.2)
If there are no reports of ongoing objectionable email from this system it will be delisted automatically in approximately 13 hours.
Causes of listing
- System has sent mail to SpamCop spam traps in the past week (spam traps are secret, no reports or evidence are provided by SpamCop)
Express-delisting is not available
Listing History
In the past 44.4 days, it has been listed 12 times for a total of 13.3 days
Can you check if the forum software uses sendgrid?
The confirmation linked to the first post in this blog entry on how to whitelist the SendGrid outgoing IP-address.
One thing I wonder: why does SendGrid use a single outgoing IP-address? If it gets blacklisted, many of their clients have problems.
Anyway: before adding the entry to my whitelist, the problem had resolved itself, and the blacklist entries were done:
Related: [Wayback/Archive] Forum Move – Scooter Forums
We’ve moved our forums to vBulletin Cloud.
New forum URL: https://forum.scootersoftware.com/
Links to the old forum will be redirected to the new URL.
If you notice any problems after the move, please let us know.
[Wayback/Archive] Forums – Scooter Forums
–jeroen
Posted in Communications Development, Development, eMail, GMail, Google, Internet protocol suite, Power User, SMTP, SocialMedia | Leave a Comment »
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
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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 »
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 »
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:
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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 »
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 »
The Wiert Corner - irregular stream of stuff 