Dnsmasq 的安全性漏洞

Google 這次出手炸的好痛:「Behind the Masq: Yet more DNS, and DHCP, vulnerabilities」。

當需要在 client 端處理 DNS 的事情,有蠻多開發者都會選擇用 Dnsmasq 處理,這次直接拉出七個 CVE (編號 CVE-2017-13704 與 CVE-2016-{14491-14496}),其中三個是 RCE:

看了一下,Ubuntu 也推出更新了,接下來有一堆機器要升級 Dnsmasq... :o

Apache 的 Optionsbleed

Apache 也出了類似 Heartbleed 的包:「Apache bug leaks contents of server memory for all to see—Patch now」,原文出自「Optionsbleed - HTTP OPTIONS method can leak Apache's server memory」。

這掛上 CVE-2017-9798 了,影響版本包括了:

This affects the Apache HTTP Server through 2.2.34 and 2.4.x through 2.4.27.

發生在對 OPTIONS 處理出問題:

Optionsbleed is a use after free error in Apache HTTP that causes a corrupted Allow header to be constructed in response to HTTP OPTIONS requests. This can leak pieces of arbitrary memory from the server process that may contain secrets. The memory pieces change after multiple requests, so for a vulnerable host an arbitrary number of memory chunks can be leaked.

就... 更新吧 @_@

在 Git/Mercurial/Subversion 上 "-" 發生的問題

在「[ANNOUNCE] Git v2.14.1, v2.13.5, and others」這邊看到 - 開頭產生的問題:

These contain a security fix for CVE-2017-1000117, and are released in coordination with Subversion and Mercurial that share a similar issue. CVE-2017-9800 and CVE-2017-1000116 are assigned to these systems, respectively, for issues similar to it that are now addressed in their part of this coordinated release.

這算是老問題了,Git 對應的修正主要是朝 filter input 的方向修正,包括了禁用 - 開頭的 hostname,以及禁止 GIT_PROXY_COMMAND- 開頭,另外是禁止開頭是 - 的 repository name:

  • A "ssh://..." URL can result in a "ssh" command line with a hostname that begins with a dash "-", which would cause the "ssh" command to instead (mis)treat it as an option. This is now prevented by forbidding such a hostname (which should not impact any real-world usage).
  • Similarly, when GIT_PROXY_COMMAND is configured, the command is run with host and port that are parsed out from "ssh://..." URL; a poorly written GIT_PROXY_COMMAND could be tricked into treating a string that begins with a dash "-" as an option. This is now prevented by forbidding such a hostname and port number (again, which should not impact any real-world usage).
  • In the same spirit, a repository name that begins with a dash "-" is also forbidden now.

然後中華電信的 DNS server (168.95.1.1 & 168.95.192.1) 都查不到 marc.info,改用 Google 的 8.8.8.8 才查得到... =_=

最近 OpenVPN 的安全性漏洞...

看到「The OpenVPN post-audit bug bonanza」這個只有苦笑啊...

作者在 OpenVPN 經過一連串的安全加強後 (包括 harden 計畫與兩個外部單位的程式碼稽核找到不少問題),決定出手挖看看:

After a hardening of the OpenVPN code (as commissioned by the Dutch intelligence service AIVD) and two recent audits 1 2, I thought it was now time for some real action ;).

然後就挖出不少問題了...

可以看到作者透過 fuzzing 打出一卡車,包含了不少 crash XDDD:(然後有一個是 stack buffer corruption,不知道有沒有機會變成 RCE)

  • Remote server crashes/double-free/memory leaks in certificate processing (CVE-2017-7521)
  • Remote (including MITM) client crash, data leak (CVE-2017-7520)
  • Remote (including MITM) client stack buffer corruption
  • Remote server crash (forced assertion failure) (CVE-2017-7508)
  • Crash mbed TLS/PolarSSL-based server (CVE-2017-7522)
  • Stack buffer overflow if long –tls-cipher is given

iOS 透過無線網路的 RCE...

在「About the security content of iOS 10.3.1」這邊的說明:

Available for: iPhone 5 and later, iPad 4th generation and later, iPod touch 6th generation and later
Impact: An attacker within range may be able to execute arbitrary code on the Wi-Fi chip
Description: A stack buffer overflow was addressed through improved input validation.
CVE-2017-6975: Gal Beniamini of Google Project Zero

這描述看起來就不太妙...

分析現在還有多少不安全的 JavaScript Library 被使用

在「Thou shalt not depend on me: analysing the use of outdated JavaScript libraries on the web」這邊看到對 JavaScript Library 的研究。

jQuery 沒有什麼疑問的還是最大宗,查了一下應該是 CVE-2011-4969 的影響,對 jQuery 1.6、1.6.1、1.6.2 三個版本有影響。

另外也提到了 hosting 的部份,可以看到 Google Hosted Libraries 還是佔有最高的比率。

cURL 接下來的安全性更新...

cURL 的維護老大放話要大家注意接下來的安全性更新:「An alert on the upcoming 7.51.0 release」。

最少 11 個安全性更新:

This release will bundle no less than _eleven_ security advisories and their associated fixes (unless we get more reported in the time we have left).

由於這些 security issue 的特性,會採取不公開的 branch 修正再 merge 回來,再加上這麼大的數量,對於穩定性的衝擊是未知的:

Merging eleven previously non-disclosed branches into master just before a release is not ideal but done so to minimize the security impact on existing users when the problems get known.

所以目前的規劃是會在 release 的 48 個小時前公開 (希望藉由這封信讓有能力的人一起集中來看),藉此來降低衝擊:

My plan is to merge them all into master and push around 48 hours before release, watch the autobuilds closesly, have a few extra coverity scans done and then fix up what's found before the release.

這安全更新的數量好像有點多 orz

Cisco 與 Fortinet 防火牆的 RCE 漏洞

NSA 使用這些漏洞來大量監聽企業的流量:「Leaked Exploits are Legit and Belong to NSA: Cisco, Fortinet and Snowden Docs Confirm」。

Cisco 已經確認這個安全性漏洞了,全系列包括已經停產的 Cisco PIX、上個世代的 Cisco ASA 5500 (但還有些型號還在賣),以及目前主力的 Cisco ASA 5500-X,另外還包括了安全模組系列也中獎:「Cisco Adaptive Security Appliance SNMP Remote Code Execution Vulnerability」。

  • Cisco ASA 5500 Series Adaptive Security Appliances
  • Cisco ASA 5500-X Series Next-Generation Firewalls
  • Cisco ASA Services Module for Cisco Catalyst 6500 Series Switches and Cisco 7600 Series Routers
  • Cisco ASA 1000V Cloud Firewall
  • Cisco Adaptive Security Virtual Appliance (ASAv)
  • Cisco Firepower 4100 Series
  • Cisco Firepower 9300 ASA Security Module
  • Cisco Firepower Threat Defense Software
  • Cisco Firewall Services Module (FWSM)*
  • Cisco Industrial Security Appliance 3000
  • Cisco PIX Firewalls*

標星號的是目前已經沒有在維護的產品,這次只確認受到影響,但不會更新:

Cisco Firewall Service Modules and Cisco PIX Firewalls have passed the last day of software support milestone as stated in the published End of Life (EoL) documents. Further investigations into these devices will not be performed, and fixed software will not be made available.

這次 Cisco 的安全性問題是 SNMP 的洞造成的:

Administrators are advised to allow only trusted users to have SNMP access and to monitor affected systems using the snmp-server host command.

這個洞被 NSA 用來寫 exploit 植入系統:

This flaw was included inside two NSA exploits, dubbed EPICBANANA as well as JETPLOW, which is an enhanced version of EPICBANANA, but with better persistence capabilities, Cisco's Omar Santos said in a blog post.

在 NSA 洩漏出來的文件裡可以看到 ace02468bdf13579 這個特殊辨識字串,而在受感染的樣本上也找到了這個痕跡:

而且不只是 Cisco,其他幾家也中獎了,可以參考「The NSA Leak Is Real, Snowden Documents Confirm」這邊更多的資訊 @_@

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...

OpenSSL 的 DSA 被 Side-channel attack 打爆

在「Make Sure DSA Signing Exponentiations Really are Constant-Time」這篇文章裡面,直接透過 end-to-end 的 timing attack 打爆 (也就是透過 internet 觀察攻擊),而不需要在同一台機器上對 cache 之類的區域攻擊:

A unique feature of our work is that we target common cryptographic protocols. Previous works that demonstrate cache-timing key-recovery attack only target the cryptographic primitives, ignoring potential cache noise from the protocol implementation. In contrast, we present end-to-end attacks on two common cryptographic protocols: SSH and TLS. We are, therefore, the first to demonstrate that cache-timing attacks are a threat not only when executing the cryptographic primitives but also in the presence of the cache activity of the whole protocol suite.

而且次數相當的少,就可以 key recovery:

260 SSH-2 handshakes to extract a 1024/160-bit DSA host key from an OpenSSH server, and 580 TLS 1.2 handshakes to extract a 2048/256-bit DSA key from an stunnel server.

CVE 編號為 CVE-2016-2178OpenSSL 全系列 (包括 fork 出去的版本) 與 OpenSSH 只要是 DSA 的實作都中獎...