The DUHK Attack:因為亂數產生器的問題而造成的安全漏洞

Bruce Schneier 那邊看到的:「Attack on Old ANSI Random Number Generator」,攻擊的網站在「The DUHK Attack」,論文在「Practical state recovery attacks against legacy RNG implementations (PDF)」。

攻擊的對象是 ANSI X9.31 Random Number Generator:

DUHK (Don't Use Hard-coded Keys) is a vulnerability that affects devices using the ANSI X9.31 Random Number Generator (RNG) in conjunction with a hard-coded seed key.

然後攻擊的對象是 FortinetFortiOS

Traffic from any VPN using FortiOS 4.3.0 to FortiOS 4.3.18 can be decrypted by a passive network adversary who can observe the encrypted handshake traffic.

如果照說明的只到 4.3.18,那麼去年 11 月更新的 4.3.19 (參考「FortiOS 4.3.19 Release Notes」) 應該是修正了?不過裡面沒翻到類似的資料,是剛好把 RNG 換掉了嗎?

Libgcrypt 與 GnuPG 的安全性問題

在「Security fixes for Libgcrypt and GnuPG 1.4 [CVE-2016-6316]」這邊看到這個歷史悠久的 bug:

Felix Dörre and Vladimir Klebanov from the Karlsruhe Institute of Technology found a bug in the mixing functions of Libgcrypt's random number generator: An attacker who obtains 4640 bits from the RNG can trivially predict the next 160 bits of output. This bug exists since 1998 in all GnuPG and Libgcrypt versions.

就這樣的行為,對於自己用的機器應該是還好... 不過得到 4640 bits 後就可以預測接下來的 160 bits,這個 RNG 有點囧 @_@

官方目前是認為應該還好:

A first analysis on the impact of this bug in GnuPG shows that existing RSA keys are not weakened. For DSA and Elgamal keys it is also unlikely that the private key can be predicted from other public information. This needs more research and I would suggest _not to_ overhasty revoke keys.

不過如果你有絕對的安全需求的話還是可以考慮 revoke 再重新生一把...

利用 WPS 實做上的問題攻擊,而取得 WPA 密碼

在「Wi-Fi Router Attack Only Requires a Single PIN Guess」這邊看到利用 WPS 實做上的弱點攻擊而取得 WPA 的密碼。

投影片取自「Offline bruteforce attack on WiFi Protected Setup」這邊:

利用各種方法攻擊,像是不夠安全的 PRNG (Pseudo Random Number Generator)。

作者的建議是,關掉 WPS 會比較安全 XD