Cobalt Strike 4.0 认证机制及破解方法详解<\/h1>

0x00 前言<\/h2>
本文详细解析Cobalt Strike 4.0的认证机制，包括完整的认证流程、关键代码分析以及可行的破解方法。4.0版本相比3.X版本增加了更复杂的验证机制，特别是引入了Sleeved模块的认证key，这使得"破解"变得更加困难。<\/p>

0x01 基础知识准备<\/h2>

1.1 RSA算法<\/h3>

加密与签名的区别：<\/strong><\/p>

加密：防止信息泄露<\/li>
签名：防止信息篡改<\/li> <\/ul>
核心原则：<\/strong><\/p>

公钥加密，私钥解密<\/li>
私钥签名，公钥验签<\/li> <\/ul>
1.2 HMAC消息摘要算法<\/h3>
MAC(Message Authentication Code)是带密钥的Hash函数，用于验证消息完整性。发送方使用共享密钥计算摘要，接收方用相同密钥验证。<\/p>
1.3 AES加密安全性<\/h3>
AES-128破解需要尝试约2^127≈1.710^38个密钥，即使以比特币网络的算力(2.5644<\/em>10^19次\/秒)也需要约2104亿年。<\/p>
0x02 认证流程分析<\/h2>
2.1 主要验证文件<\/h3>

cobaltstrike.auth<\/code>：授权文件<\/li>
authkey.pub<\/code>：RSA公钥文件<\/li> <\/ul> 2.2 核心验证类<\/h3> License<\/code>：许可证检查入口<\/li> Authorization<\/code>：授权文件解析<\/li> AuthCrypto<\/code>：RSA解密和解压<\/li> SleevedResource<\/code>：4.0新增的深层验证<\/li> SleeveSecurity<\/code>：处理Sleeved模块的加密验证<\/li> <\/ul> 2.3 认证流程<\/h3> 初始验证<\/strong>：<\/p> 检查cobaltstrike.auth<\/code>文件是否存在<\/li> 使用AuthCrypto<\/code>解密文件内容<\/li> 验证文件头和数据格式<\/li> <\/ul> <\/li> 授权文件解析<\/strong>：<\/p> 读取有效期标志(29999999表示永久)<\/li> 获取水印值(影响生成的shellcode)<\/li> 提取16字节的Sleeved解密key<\/li> <\/ul> <\/li> Sleeved模块验证<\/strong>：<\/p> 使用授权文件中的key派生AES和HMAC密钥<\/li> 验证内置DLL\/EXE文件的HMAC<\/li> 解密并加载这些资源文件<\/li> <\/ul> <\/li> <\/ol> 0x03 关键代码分析<\/h2> 3.1 License.checkLicenseGUI()<\/h3> public<\/span> static<\/span> void<\/span> checkLicenseGUI<\/span>(<\/span>Authorization var0)<\/span> {<\/span> <\/span><\/span> if<\/span> (!<\/span>var0.<\/span>isValid<\/span>())<\/span> {<\/span> \/\/ 检查授权文件有效性 <\/span><\/span><\/span><\/span> CommonUtils.<\/span>print_error<\/span>(<\/span>"Your authorization file is not valid: "<\/span> +<\/span> var0.<\/span>getError<\/span>());<\/span> <\/span><\/span> System.<\/span>exit<\/span>(<\/span>0<\/span>);<\/span> <\/span><\/span> }<\/span> <\/span><\/span> if<\/span> (!<\/span>var0.<\/span>isPerpetual<\/span>())<\/span> {<\/span> \/\/ 检查是否永久授权 <\/span><\/span><\/span><\/span> if<\/span> (<\/span>var0.<\/span>isExpired<\/span>())<\/span> {<\/span> \/\/ 检查是否过期 <\/span><\/span><\/span><\/span> CommonUtils.<\/span>print_error<\/span>(<\/span>"Your Cobalt Strike license is expired..."<\/span>);<\/span> <\/span><\/span> System.<\/span>exit<\/span>(<\/span>0<\/span>);<\/span> <\/span><\/span> }<\/span> <\/span><\/span> if<\/span> (<\/span>var0.<\/span>isAlmostExpired<\/span>())<\/span> {<\/span> \/\/ 检查是否即将过期 <\/span><\/span><\/span><\/span> CommonUtils.<\/span>print_warn<\/span>(<\/span>"Your Cobalt Strike license expires in "<\/span> +<\/span> var0.<\/span>whenExpires<\/span>());<\/span> <\/span><\/span> }<\/span> <\/span><\/span> }<\/span> <\/span><\/span>}<\/span> <\/span><\/span><\/code><\/pre>3.2 Authorization类核心逻辑<\/h3> public<\/span> Authorization<\/span>()<\/span> {<\/span> <\/span><\/span> \/\/ 读取cobaltstrike.auth文件 <\/span><\/span><\/span><\/span> byte<\/span>[]<\/span> arrayOfByte1 =<\/span> CommonUtils.<\/span>readFile<\/span>(<\/span>str);<\/span> <\/span><\/span> AuthCrypto authCrypto =<\/span> new<\/span> AuthCrypto();<\/span> <\/span><\/span> byte<\/span>[]<\/span> arrayOfByte2 =<\/span> authCrypto.<\/span>decrypt<\/span>(<\/span>arrayOfByte1);<\/span> \/\/ RSA解密 <\/span><\/span><\/span><\/span> <\/span><\/span> DataParser dataParser =<\/span> new<\/span> DataParser(<\/span>arrayOfByte2);<\/span> <\/span><\/span> int<\/span> i =<\/span> dataParser.<\/span>readInt<\/span>();<\/span> \/\/ 读取有效期标志 <\/span><\/span><\/span><\/span> this<\/span>.<\/span>watermark<\/span> =<\/span> dataParser.<\/span>readInt<\/span>();<\/span> \/\/ 读取水印值 <\/span><\/span><\/span><\/span> byte<\/span> j =<\/span> dataParser.<\/span>readByte<\/span>();<\/span> \/\/ 版本标识(必须≥40) <\/span><\/span><\/span><\/span> byte<\/span> k =<\/span> dataParser.<\/span>readByte<\/span>();<\/span> \/\/ key长度(必须=16) <\/span><\/span><\/span><\/span> byte<\/span>[]<\/span> arrayOfByte3 =<\/span> dataParser.<\/span>readBytes<\/span>(<\/span>k);<\/span> \/\/ 读取16字节key <\/span><\/span><\/span><\/span> <\/span><\/span> SleevedResource.<\/span>Setup<\/span>(<\/span>arrayOfByte3);<\/span> \/\/ 初始化Sleeved验证 <\/span><\/span><\/span><\/span>}<\/span> <\/span><\/span><\/code><\/pre>3.3 AuthCrypto解密过程<\/h3> public<\/span> byte<\/span>[]<\/span> decrypt<\/span>(<\/span>byte<\/span>[]<\/span> paramArrayOfByte)<\/span> {<\/span> <\/span><\/span> byte<\/span>[]<\/span> arrayOfByte1 =<\/span> this<\/span>.<\/span>_decrypt<\/span>(<\/span>paramArrayOfByte);<\/span> \/\/ RSA解密 <\/span><\/span><\/span><\/span> DataParser localDataParser =<\/span> new<\/span> DataParser(<\/span>arrayOfByte1);<\/span> <\/span><\/span> localDataParser.<\/span>big<\/span>();<\/span> <\/span><\/span> int<\/span> i =<\/span> localDataParser.<\/span>readInt<\/span>();<\/span> \/\/ 验证文件头 <\/span><\/span><\/span><\/span> if<\/span> (<\/span>i !=<\/span> -<\/span>889274157<\/span>)<\/span> {<\/span> \/\/ 正确文件头值 <\/span><\/span><\/span><\/span> this<\/span>.<\/span>error<\/span> =<\/span> "bad header"<\/span>;<\/span> <\/span><\/span> return<\/span> new<\/span> byte<\/span>[<\/span>0<\/span>];<\/span> <\/span><\/span> }<\/span> <\/span><\/span> int<\/span> j =<\/span> localDataParser.<\/span>readShort<\/span>();<\/span> <\/span><\/span> byte<\/span>[]<\/span> arrayOfByte2 =<\/span> localDataParser.<\/span>readBytes<\/span>(<\/span>j);<\/span> \/\/ 返回有效载荷 <\/span><\/span><\/span><\/span> return<\/span> arrayOfByte2;<\/span> <\/span><\/span>}<\/span> <\/span><\/span><\/code><\/pre>3.4 SleevedResource验证机制<\/h3> public<\/span> void<\/span> registerKey<\/span>(<\/span>byte<\/span>[]<\/span> paramArrayOfByte)<\/span> {<\/span> <\/span><\/span> MessageDigest localMessageDigest =<\/span> MessageDigest.<\/span>getInstance<\/span>(<\/span>"SHA-256"<\/span>);<\/span> <\/span><\/span> byte<\/span>[]<\/span> arrayOfByte1 =<\/span> localMessageDigest.<\/span>digest<\/span>(<\/span>paramArrayOfByte);<\/span> <\/span><\/span> byte<\/span>[]<\/span> arrayOfByte2 =<\/span> Arrays.<\/span>copyOfRange<\/span>(<\/span>arrayOfByte1,<\/span> 0<\/span>,<\/span> 16<\/span>);<\/span> \/\/ AES密钥 <\/span><\/span><\/span><\/span> byte<\/span>[]<\/span> arrayOfByte3 =<\/span> Arrays.<\/span>copyOfRange<\/span>(<\/span>arrayOfByte1,<\/span> 16<\/span>,<\/span> 32<\/span>);<\/span> \/\/ HMAC密钥 <\/span><\/span><\/span><\/span> this<\/span>.<\/span>key<\/span> =<\/span> new<\/span> SecretKeySpec(<\/span>arrayOfByte2,<\/span> "AES"<\/span>);<\/span> <\/span><\/span> this<\/span>.<\/span>hash_key<\/span> =<\/span> new<\/span> SecretKeySpec(<\/span>arrayOfByte3,<\/span> "HmacSHA256"<\/span>);<\/span> <\/span><\/span>}<\/span> <\/span><\/span><\/code><\/pre>0x04 破解方法<\/h2> 4.1 授权文件结构<\/h3> 有效的.auth<\/code>文件解密后应包含以下结构：<\/p> 偏移<\/th> 长度<\/th> 说明<\/th> 示例值<\/th> <\/tr> <\/thead> 0-3<\/td> 4字节<\/td> 文件头<\/td> 0xCAFEC0D3<\/td> <\/tr> 4-5<\/td> 2字节<\/td> 数据长度<\/td> 0x002B<\/td> <\/tr> 6-9<\/td> 4字节<\/td> 有效期标志<\/td> 0x01C9C37F (29999999)<\/td> <\/tr> 10-13<\/td> 4字节<\/td> 水印值<\/td> 0x0022907F<\/td> <\/tr> 14<\/td> 1字节<\/td> 版本标识<\/td> 0x10 (必须≥40)<\/td> <\/tr> 15<\/td> 1字节<\/td> key长度<\/td> 0x10 (必须=16)<\/td> <\/tr> 16-31<\/td> 16字节<\/td> Sleeved key<\/td> 随机16字节<\/td> <\/tr> <\/tbody> <\/table> 4.2 完整破解步骤<\/h3> 生成RSA密钥对<\/strong>：<\/p> openssl genrsa -out private.pem 2048<\/span> <\/span><\/span>openssl rsa -in private.pem -pubout -out public.pem <\/span><\/span><\/code><\/pre><\/li> 构造授权数据<\/strong>：<\/p> 使用以下16字节key(4.0版本)： {27, -27, -66, 82, -58, 37, 92, 51, 85, -114, -118, 28, -74, 103, -53, 6}<\/code><\/li> <\/ul> <\/li> 计算authkey.pub的MD5<\/strong>：<\/p> 替换AuthCrypto.load()<\/code>中的MD5值： if<\/span> (!<\/span>"8bb4df00c120881a1945a43e2bb2379e"<\/span>.<\/span>equals<\/span>(<\/span>CommonUtils.<\/span>toHex<\/span>(<\/span>arrayOfByte2)))<\/span> <\/span><\/span><\/code><\/pre><\/li> <\/ul> <\/li> 加密授权数据<\/strong>：<\/p> 使用私钥加密构造好的数据<\/li> <\/ul> <\/li> 替换文件<\/strong>：<\/p> 将加密后的数据保存为cobaltstrike.auth<\/code><\/li> 替换authkey.pub<\/code>为你生成的公钥文件<\/li> <\/ul> <\/li> <\/ol> 4.3 替代破解方法<\/h3> 方法一：硬编码key<\/h4> 直接修改Authorization<\/code>类，跳过文件读取和RSA解密，硬编码有效数据：<\/p> byte<\/span>[]<\/span> arrayOfByte2 =<\/span> {<\/span>1<\/span>,<\/span> -<\/span>55<\/span>,<\/span> -<\/span>61<\/span>,<\/span> 127<\/span>,<\/span> 0<\/span>,<\/span> 0<\/span>,<\/span> 34<\/span>,<\/span> -<\/span>112<\/span>,<\/span> 127<\/span>,<\/span> 16<\/span>,<\/span> 27<\/span>,<\/span> -<\/span>27<\/span>,<\/span> -<\/span>66<\/span>,<\/span> 82<\/span>,<\/span> -<\/span>58<\/span>,<\/span> 37<\/span>,<\/span> 92<\/span>,<\/span> 51<\/span>,<\/span> 85<\/span>,<\/span> -<\/span>114<\/span>,<\/span> -<\/span>118<\/span>,<\/span> 28<\/span>,<\/span> -<\/span>74<\/span>,<\/span> 103<\/span>,<\/span> -<\/span>53<\/span>,<\/span> 6<\/span>};<\/span> <\/span><\/span><\/code><\/pre>方法二：使用CSHook.jar<\/h4> 通过Java Agent机制在运行时替换Authorization<\/code>类，无需修改原始jar包：<\/p> public<\/span> class<\/span> Transformer<\/span> implements<\/span> ClassFileTransformer {<\/span> <\/span><\/span> public<\/span> byte<\/span>[]<\/span> transform<\/span>(<\/span>ClassLoader loader,<\/span> String className,<\/span> <\/span><\/span> Class classBeingRedefined,<\/span> <\/span><\/span> ProtectionDomain protectionDomain,<\/span> <\/span><\/span> byte<\/span>[]<\/span> classfileBuffer)<\/span> {<\/span> <\/span><\/span> if<\/span> (<\/span>className.<\/span>equals<\/span>(<\/span>"common\/Authorization"<\/span>))<\/span> {<\/span> <\/span><\/span> \/\/ 替换为Base64编码的修改后类文件 <\/span><\/span><\/span><\/span> return<\/span> Base64.<\/span>getDecoder<\/span>().<\/span>decode<\/span>(<\/span>"..."<\/span>);<\/span> <\/span><\/span> }<\/span> <\/span><\/span> return<\/span> classfileBuffer;<\/span> <\/span><\/span> }<\/span> <\/span><\/span>}<\/span> <\/span><\/span><\/code><\/pre>0x05 注意事项<\/h2> 4.1版本使用不同的key： {1, -55, -61, 127, 0, 0, 34, -112, 127, 16, -128, -29, 42, 116, 32, 96, -72, -124, 65, -101, -96, -63, 113, -55, -86, 118}<\/code><\/p> <\/li> Sleeved模块验证失败会导致功能受限，错误信息： [Sleeve] Bad HMAC on xxxxx byte message from resource<\/code><\/p> <\/li> 完全破解需要同时满足：<\/p> 通过初始授权验证<\/li> 提供正确的Sleeved解密key<\/li> <\/ul> <\/li> 从安全角度考虑，建议购买正版授权而非使用破解版本。<\/p> <\/li> <\/ol>

偏移<\/th>	长度<\/th>	说明<\/th>	示例值<\/th> <\/tr> <\/thead>
0-3<\/td>	4字节<\/td>	文件头<\/td>	0xCAFEC0D3<\/td> <\/tr>
4-5<\/td>	2字节<\/td>	数据长度<\/td>	0x002B<\/td> <\/tr>
6-9<\/td>	4字节<\/td>	有效期标志<\/td>	0x01C9C37F (29999999)<\/td> <\/tr>
10-13<\/td>	4字节<\/td>	水印值<\/td>	0x0022907F<\/td> <\/tr>
14<\/td>	1字节<\/td>	版本标识<\/td>	0x10 (必须≥40)<\/td> <\/tr>
15<\/td>	1字节<\/td>	key长度<\/td>	0x10 (必须=16)<\/td> <\/tr>
16-31<\/td>	16字节<\/td>	Sleeved key<\/td>	随机16字节<\/td> <\/tr> <\/tbody> <\/table> 4.2 完整破解步骤<\/h3> 生成RSA密钥对<\/strong>：<\/p> openssl genrsa -out private.pem 2048<\/span> <\/span><\/span>openssl rsa -in private.pem -pubout -out public.pem <\/span><\/span><\/code><\/pre><\/li> 构造授权数据<\/strong>：<\/p> 使用以下16字节key(4.0版本)： {27, -27, -66, 82, -58, 37, 92, 51, 85, -114, -118, 28, -74, 103, -53, 6}<\/code><\/li> <\/ul> <\/li> 计算authkey.pub的MD5<\/strong>：<\/p> 替换AuthCrypto.load()<\/code>中的MD5值： if<\/span> (!<\/span>"8bb4df00c120881a1945a43e2bb2379e"<\/span>.<\/span>equals<\/span>(<\/span>CommonUtils.<\/span>toHex<\/span>(<\/span>arrayOfByte2)))<\/span> <\/span><\/span><\/code><\/pre><\/li> <\/ul> <\/li> 加密授权数据<\/strong>：<\/p> 使用私钥加密构造好的数据<\/li> <\/ul> <\/li> 替换文件<\/strong>：<\/p> 将加密后的数据保存为cobaltstrike.auth<\/code><\/li> 替换authkey.pub<\/code>为你生成的公钥文件<\/li> <\/ul> <\/li> <\/ol> 4.3 替代破解方法<\/h3> 方法一：硬编码key<\/h4> 直接修改Authorization<\/code>类，跳过文件读取和RSA解密，硬编码有效数据：<\/p> byte<\/span>[]<\/span> arrayOfByte2 =<\/span> {<\/span>1<\/span>,<\/span> -<\/span>55<\/span>,<\/span> -<\/span>61<\/span>,<\/span> 127<\/span>,<\/span> 0<\/span>,<\/span> 0<\/span>,<\/span> 34<\/span>,<\/span> -<\/span>112<\/span>,<\/span> 127<\/span>,<\/span> 16<\/span>,<\/span> 27<\/span>,<\/span> -<\/span>27<\/span>,<\/span> -<\/span>66<\/span>,<\/span> 82<\/span>,<\/span> -<\/span>58<\/span>,<\/span> 37<\/span>,<\/span> 92<\/span>,<\/span> 51<\/span>,<\/span> 85<\/span>,<\/span> -<\/span>114<\/span>,<\/span> -<\/span>118<\/span>,<\/span> 28<\/span>,<\/span> -<\/span>74<\/span>,<\/span> 103<\/span>,<\/span> -<\/span>53<\/span>,<\/span> 6<\/span>};<\/span> <\/span><\/span><\/code><\/pre>方法二：使用CSHook.jar<\/h4> 通过Java Agent机制在运行时替换Authorization<\/code>类，无需修改原始jar包：<\/p> public<\/span> class<\/span> Transformer<\/span> implements<\/span> ClassFileTransformer {<\/span> <\/span><\/span> public<\/span> byte<\/span>[]<\/span> transform<\/span>(<\/span>ClassLoader loader,<\/span> String className,<\/span> <\/span><\/span> Class classBeingRedefined,<\/span> <\/span><\/span> ProtectionDomain protectionDomain,<\/span> <\/span><\/span> byte<\/span>[]<\/span> classfileBuffer)<\/span> {<\/span> <\/span><\/span> if<\/span> (<\/span>className.<\/span>equals<\/span>(<\/span>"common\/Authorization"<\/span>))<\/span> {<\/span> <\/span><\/span> \/\/ 替换为Base64编码的修改后类文件 <\/span><\/span><\/span><\/span> return<\/span> Base64.<\/span>getDecoder<\/span>().<\/span>decode<\/span>(<\/span>"..."<\/span>);<\/span> <\/span><\/span> }<\/span> <\/span><\/span> return<\/span> classfileBuffer;<\/span> <\/span><\/span> }<\/span> <\/span><\/span>}<\/span> <\/span><\/span><\/code><\/pre>0x05 注意事项<\/h2> 4.1版本使用不同的key： {1, -55, -61, 127, 0, 0, 34, -112, 127, 16, -128, -29, 42, 116, 32, 96, -72, -124, 65, -101, -96, -63, 113, -55, -86, 118}<\/code><\/p> <\/li> Sleeved模块验证失败会导致功能受限，错误信息： [Sleeve] Bad HMAC on xxxxx byte message from resource<\/code><\/p> <\/li> 完全破解需要同时满足：<\/p> 通过初始授权验证<\/li> 提供正确的Sleeved解密key<\/li> <\/ul> <\/li> 从安全角度考虑，建议购买正版授权而非使用破解版本。<\/p> <\/li> <\/ol>

Cobalt Strike 4.0 认证机制及破解方法详解<\/h1>

0x00 前言<\/h2> 本文详细解析Cobalt Strike 4.0的认证机制，包括完整的认证流程、关键代码分析以及可行的破解方法。4.0版本相比3.X版本增加了更复杂的验证机制，特别是引入了Sleeved模块的认证key，这使得"破解"变得更加困难。<\/p>

0x01 基础知识准备<\/h2>

1.2 HMAC消息摘要算法<\/h3> MAC(Message Authentication Code)是带密钥的Hash函数，用于验证消息完整性。发送方使用共享密钥计算摘要，接收方用相同密钥验证。<\/p>

1.3 AES加密安全性<\/h3> AES-128破解需要尝试约2^127≈1.710^38个密钥，即使以比特币网络的算力(2.5644<\/em>10^19次\/秒)也需要约2104亿年。<\/p>

0x03 关键代码分析<\/h2>

0x04 破解方法<\/h2>

4.3 替代破解方法<\/h3>

0x00 前言<\/h2>
本文详细解析Cobalt Strike 4.0的认证机制，包括完整的认证流程、关键代码分析以及可行的破解方法。4.0版本相比3.X版本增加了更复杂的验证机制，特别是引入了Sleeved模块的认证key，这使得"破解"变得更加困难。<\/p>

1.2 HMAC消息摘要算法<\/h3>
MAC(Message Authentication Code)是带密钥的Hash函数，用于验证消息完整性。发送方使用共享密钥计算摘要，接收方用相同密钥验证。<\/p>

1.3 AES加密安全性<\/h3>
AES-128破解需要尝试约2^127≈1.710^38个密钥，即使以比特币网络的算力(2.5644<\/em>10^19次\/秒)也需要约2104亿年。<\/p>