Ask HN: Scam from `service@paypal.com` email, How?
I asked GPT4 & dig on mx2.phx.paypal.com matches 66.211.170.88.

Sender IP and SPF: The SPF record indicates that the email was sent from IP 66.211.170.88 and that this IP is a designated sender for paypal.com. This is a good sign, as SPF is a method for domain owners to specify which IPs are allowed to send emails on their behalf. Still, this can be faked in phishing emails, so it isn't an absolute proof.

DKIM Signature: DKIM provides an encryption-based method to validate the authenticity and integrity of a message. The DKIM-Signature indicates that the email is signed and suggests it genuinely came from paypal.com with the signature being verified. This is another positive sign.

DMARC: The DMARC record shows a pass for the email. DMARC builds on SPF and DKIM to give receivers a way to improve and monitor the protection of the domain from fraudulent email. This is another good indication that the email is genuine.

Helo Record: The email identifies itself as coming from mx2.phx.paypal.com. Cross-referencing this with the IP 66.211.170.88 can give more information. Ideally, a DNS lookup on this domain should resolve to this IP, or vice versa.
Authentication-Results: spf=pass (sender IP is 66.211.170.88)

smtp.mailfrom=paypal.com; dkim=pass (signature was verified)

header.d=paypal.com;dmarc=pass action=none

header.from=paypal.com;compauth=pass reason=100

Received-SPF: Pass (protection.outlook.com: domain of paypal.com designates

66.211.170.88 as permitted sender) receiver=protection.outlook.com;

client-ip=66.211.170.88; helo=mx2.phx.paypal.com; pr=C

Received: from mx2.phx.paypal.com (66.211.170.88) by

AM7EUR06FT065.mail.protection.outlook.com (10.233.255.252) with Microsoft

SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id

15.20.6723.11 via Frontend Transport; Mon, 21 Aug 2023 14:39:41 +0000

X-IncomingTopHeaderMarker:

OriginalChecksum:D3EF06AD4D210DE94DD4CEF7676ADB33FFADDA146826968760B256614DBA0BB3;UpperCasedChecksum:C166224836B8549C000E1248A8D0B21B268DA10BAE404535ECAE6D2AC1E4F7F4;SizeAsReceived:1198;Count:17

DKIM-Signature: v=1; a=rsa-sha256; d=paypal.com; s=pp-dkim1; c=relaxed/relaxed;

q=dns/txt; i=@paypal.com; t=1692628775;

h=From:From:Subject:Date:To:MIME-Version:Content-Type;

bh=y3PR47e+bNTQkjaVkSmH1awii6kjs/uhFtgV+UQXT64=;

b=Y75EdoYH0VTDJ+1oaj5hM8Ev5CFNJxLSoLPSF6ICH/o4WEEW1kKZUvQDi63VGPd5

LxThPfH3DOqpW/o/mi8AmnbRaSfuYR2vhSIVYMXghc0VQ4CKD9J06JjDN2IO5M7/

lfWDOrXZJEAbJcSr92SnOucKMwoDngZiB2gy7SJG17187W2zmGjqZAFzNton8ssu

3aM6RRfFS+JxDEpuX3XPxYzQQsczTy2Qn/L28Yl+cJ4/HaV7myzte2OGr0qi+cQw

UEyT8Gd345qdkpxBmBUAk9Tu/Wcb6gQUdm+cDymkdcnPsuOKuW6DBgj47c76Arxw

20exiKh305Upy67mHCHvAA==;

Content-Transfer-Encoding: quoted-printable

Content-Type: text/html; charset="UTF-8"

Date: Mon, 21 Aug 2023 07:39:35 -0700

Message-ID: <53.BB.28950.72773E46@ccg01mail04>

X-PP-REQUESTED-TIME: 1692628766599

X-PP-Email-transmission-Id: 8a9be26e-4030-11ee-bba5-40a6b729312c

PP-Correlation-Id: b2d6ca346679c

*Subject: Invoice from Marquis Pleasants (0084)*

X-MaxCode-Template: RT000238

To: <xxxxxxxxxxxxxxxxxxxxxxx>

From: "service@paypal.com" <service@paypal.com>

X-Email-Type-Id: RT000238

X-PP-Priority: 0-none-true

AMQ-Delivery-Message-Id: nullval

X-XPT-XSL-Name: nullval

X-IncomingHeaderCount: 17

....

X-Microsoft-Antispam: BCL:5;

X-MS-Exchange-CrossTenant-OriginalArrivalTime: 21 Aug 2023 14:39:41.5613

(UTC)

...

X-Microsoft-Antispam-Mailbox-Delivery: