Tag: pin

在 PPA 裡面只安裝特定軟體的方式

Ubuntu 20.04 的 rsync 內建只有 3.1.3 (參考「Ubuntu – Package Search Results -- rsync」這邊)，但 --mkpath 這個參數需要 3.2.3+ 才能跑：「How can I configure rsync to create target directory on remote server?」，所以就要找 PPA 看看有沒有人有包新版的可以用。

在「Utilities - various (Xenial & newer)」這邊可以看到 Rob Savoury 有包，但發現這包有一堆軟體，我不想要裝這麼多，所以就用 Pinning 限制。

用 apt-cache policy 可以看到 o= 的值，然後就可以在 /etc/apt/preferences.d/savoury1-utilities 裡設定 rsync 的 Pin-Priority 是 1001，而其他的都掛到 -1。

Package: *
Pin: release o=LP-PPA-savoury1-utilities
Pin-Priority: -1

Package: rsync
Pin: release o=LP-PPA-savoury1-utilities
Pin-Priority: 1001

但跑 apt upgrade 沒看到可以升級，而直接 apt install rsync 的時候可以看到是因為 libxxhash0 跟不上新版而產生錯誤訊息：

The following packages have unmet dependencies:
 rsync : Depends: libxxhash0 (>= 0.8.0) but 0.7.3-1 is to be installed
E: Unable to correct problems, you have held broken packages.

所以一起加進去變成：

Package: *
Pin: release o=LP-PPA-savoury1-utilities
Pin-Priority: -1

Package: libxxhash0 rsync
Pin: release o=LP-PPA-savoury1-utilities
Pin-Priority: 1001

然後就可以 apt upgrade 升級上去了。

利用手機的 sensor 取得 PIN 碼

把 side-channel information 配合上統計方法就可以達到 74% 的正確率：「Phone Hack Uses Sensors To Steal PINs」。

透過 browser 的 javascript 就可以拉出這些資料，然後利用這些資料去猜你的手機 PIN 碼：

Researchers from U.K.-based Newcastle University created a JavaScript app called PINlogger.js that has the ability to access data generated by the phone’s sensors, including GPS, camera, microphone, accelerometer, magnetometer, proximity, gyroscope, pedometer and NFC protocols.

而且當可以多抓到更多資訊時 (像是第二次輸入) 準確度就更高了：

Using a sample set of 50 PINs, researchers found that their script was able to correctly guess a user’s PIN 74 percent of the time on the first try, which increases to 86 and 94 percent success rates on the second and third attempts.

有些瀏覽器有做一些修正，讓 side-channel information 變少，於是難度變高：

As for Firefox, starting from version 46 (released in April 2016), the browser restricts JavaScript access to motion and orientation sensors. Apple’s Security Updates for iOS 9.3 (released in March 2016), suspended the availability of motion and orientation data when the web view is hidden, according to researchers.

Google 則是沒修：

As for Google, it’s unclear what measures have been taken. “Our concern is confirmed by members in the Google Chromium team, who also believe that the issue remains unresolved,” the report stated. Google did not reply to a request to comment for this report.

這攻擊方式頗不賴... @_@

透過手機螢幕上的餘熱猜測 PIN 碼

利用手機螢幕上的餘熱分析可能的 PIN 碼：「Heat traces left by fingers can reveal your smartphone PIN」，在輸入完 PIN 碼的 30 秒內的準確度都還是很高 (80%)：

The report further revealed that if the thermal image is collected within 15 seconds of a PIN being entered, the technique is accurate almost 90% of the time. At 30 seconds, this accuracy decreased slightly to 80%. At 45 seconds or more, the accuracy dropped to 35% and below.

四位數密碼的分佈

分析信用卡四位數密碼的分佈：「PIN number analysis」。

透過已經外洩的資料分析：

Obviously, I don’t have access to a credit card PIN number database. Instead I’m going to use a proxy. I’m going to use data condensed from released/exposed/discovered password tables and security breaches.

19xx 那邊特別高，拉出來看可以看到分佈：(很像是出生年 XDDD)

相同的 abab (前兩碼與後兩碼相同) 也可以看出特別高，而 aaaa (四碼都一樣) 的特別亮：

當不只四碼時，也有一些數據：

另外是特別高的 1004 的原因：

Many people also asked the significance of 1004 in the four character PIN table. This comes from Korean speakers. When spoken, "1004" is cheonsa (cheon = 1000, sa=4).

"Cheonsa" also happens to be the Korean word for Angel.