網絡釣魚電郵剖析 (revised)

垃圾電郵主要有二種：Spam 主要是廣告，乾脆刪掉或過濾掉便是。Phishing 是釣魚，貌似來自正當商業，和個人帳戶有關，要求回應，或點擊鏈接，提供個人信息。

例如下麵的截圖來自Venmo, 看似正當，其實是騙取個人信息，你一旦回應，輕則證明你的電郵地址存在和active, 重則把敏感的個人隱私信息拱手送給對方。

 

 

 

 

 

 

 

 

 

 

 

 

對付的方法是仔細查閱來信的header, 其中的信息可以證明郵件的來龍去脈（在互聯網上走過的路逕）和真正來源。

Header 在哪？每個正當的電郵係統都有header的裝置, 但是位置各異，請參閱：

https://mxtoolbox.com/Public/Content/EmailHeaders/

 

提醒：IT 係統更新變動頻仍，上鍵的信息不一定是current.

以下是找出（筆者常用） Yahoo 電郵header 的步驟 (限於電腦版本。不適用於手機app 版。）

1. 打開郵件。
2. 點擊 More …
3. 選擇View Raw Message.

Raw Message shows:

 

The email came from [e-mail], not venmo.com. The host was mail-qv1-f102.google.com. The origination IP address 209.85.219.102 is located west of Wichita, Kansas. 

 

Also:

Received-SPF: none (domain of superbabs.store does not designate permitted sender hosts)

dkim=unknown;

spf=none smtp.mailfrom=superbabs.store;

dmarc=fail

 

Explanation:

spf: Sender Policy Framework

dkim: Domain Keys Identified Mail

dmarc: Domain-based Message Authentication, Reporting, and Conformance. 

 

In a legitimate email, all these 3 parameters should show "Pass."

The email asks me to upload ID documents. However, searching the raw message and could not find any key words in the email. Why? The email text was encrypted to hide the origination. 

The email used RSA SHA-256 cryptographic hash algorithm, which cannot be reversed to produce the original data.