勒索信内容摘要: "YOUR FILES ARE ENCRYPTED... You are not able to decrypt it by yourself!... We have been in your network for a long time..." 攻击者极具挑衅地宣称已在网络中潜伏已久,并威胁若不联系将公开数据。
YOUR FILES ARE ENCRYPTED
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Your files, documents, photos, databases and other important files are encrypted.
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You are not able to decrypt it by yourself! The only method of recovering files is to purchase an unique private key.
Only we can give you this key and only we can recover your files.
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To be sure we have the decryptor and it works you can send an email: edatax@airmail.cc and decrypt one file for free.
But this file should be of not valuable!
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Do you really want to restore your files?
Write to email: edatax@airmail.cc
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YOUR PERSONAL ID: 896F70DF-1E6B-FF95-8533-7CE58E9D2FC6
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Attention!
* Do not rename encrypted files.
* Do not try to decrypt your data using third party software, it may cause permanent data loss.
* Decryption of your files with the help of third parties may cause increased price (they add their fee to our) or you can become a victim of a scam.
* We have been in your network for a long time. We know everything about your company most of your information has already been downloaded to our server. We recommend you to do not waste your time if you dont wont we start 2nd part.
* You have 24 hours to contact us.
* Otherwise, your data will be sold or made public. 3.3 加密测试
我们使用一个名为 sierting.txt 的文件进行加密测试。 图6 sierting.txt 原始内容 图7 原始文件的十六进制视图
经过加密后,文件内容变得不可读,且头部结构发生了明显变化。 图8 加密后文件的十六进制视图 4.逆向分析:拆解加密流程
通过对样本的深入逆向分析,我们还原了 BEAST 在 Windows 环境下的完整执行逻辑。其行为模式严谨且具有针对性。 4.1 程序执行流程图
在正式加密前,样本会执行一系列环境检查和系统破坏操作: 图9 程序执行流程图 4.2 详细行为分析 4.2.1 地区白名单检查 (Region Check)
程序运行伊始,首先通过 GetLocaleInfoW 获取受害主机的系统语言信息。随后,它会对解密出的白名单国家代码进行比对。 图10 GetLocaleInfoW 代码视图
进行对资源解密操作,解密出字符串: 图11 字符串解密代码视图