0x01 Microsoft Windows
Microsoft Windows是美国微软公司以图形用户界面为基础研发的操作系统 ，主要运用于计算机、智能手机等设备。共有普通版本、服务器版本（Windows Server）、手机版本（Windows Phone）、嵌入式版本（Windows CE、Windows for IoT）等子系列，是全球应用最广泛的操作系统之一。
0x02 漏洞简介
微软上月发布的补丁包含一个可能执行代码的TCP/IP协议漏洞。tcpip.sys在对ipv6数据包进行重组时，NextHeaderOffset可能超出缓冲区范围，导致越界写的发生，利用该漏洞可以实现远程命令执行
0x03 漏洞详解
漏洞发生时，为如下函数调用栈
0: kd> kb# RetAddr : Args to Child : Call Site00 fffff80a`1f1842ea : ffffb00e`0cbef000 ffffb00e`0d333270 ffffb00e`0f5b4890 ffffb00e`00000050 : tcpip!Ipv6pReassembleDatagram+0x1e301 fffff80a`1f184442 : ffffb00e`00000000 fffff80a`1f1c61e8 00000000`00000000 ffffb00e`0d3138f0 : tcpip!Ipv6pReceiveFragment+0xae202 fffff80a`1f03bfdf : ffffb00e`0cbef000 ffffb00e`0cbef000 00000000`00000001 00000000`0000002b : tcpip!Ipv6pReceiveFragmentList+0x4203 fffff80a`1f03de45 : fffff80a`1f1c1240 ffffb00e`0c8ec940 00000000`00000001 ffffb00e`0cbef000 : tcpip!IppReceiveHeaderBatch+0x3ef04 fffff80a`1f044131 : ffffb00e`0d31eb90 ffffb00e`0d23e9c0 fffff803`94d7b001 00000000`00000000 : tcpip!IppFlcReceivePacketsCore+0x31505 fffff80a`1f043e12 : 00000000`00000017 fffff803`00000001 fffff80a`1f001bf0 ffffb00e`0d23e901 : tcpip!FlpReceiveNonPreValidatedNetBufferListChain+0x27106 fffff803`92ebce75 : 00000000`00000002 fffff803`931d1980 fffff80a`1f043d50 fffff803`94d7b1f0 : tcpip!FlReceiveNetBufferListChainCalloutRoutine+0xc207 fffff80a`1f0023a6 : ffffb00e`0cc1b7b0 00000000`00000000 ffffb00e`0c7ff870 ffffb00e`0d23e900 : nt!KeExpandKernelStackAndCalloutInternal+0x8508 fffff80a`1e10392e : 00000000`00000000 fffff803`94d7b2c0 00000000`00000001 fffff80a`1de5f20d : tcpip!FlReceiveNetBufferListChain+0xb609 fffff80a`1e1028cc : fffff80a`1f522801 fffff803`94d7dd86 0000000e`00000000 fffff80a`00000001 : NDIS!ndisMIndicateNetBufferListsToOpen+0x11e0a fffff80a`1eca6156 : 00000000`00000000 00000000`00000000 ffffb00e`0d0f4e40 ffffb00e`0d23e930 : NDIS!NdisMIndicateReceiveNetBufferLists+0x31c0b fffff80a`1eca73e3 : ffffb00e`0d23e900 00000000`00000001 ffffb00e`0d0f4e40 fffff803`94d7b588 : e1i63x64!RECEIVE::RxIndicateNBLs+0x1320c fffff80a`1ecae315 : ffffb00e`0c483830 ffffb00e`0d0f4000 ffffb00e`0d0f4001 fffff803`00000000 : e1i63x64!RECEIVE::RxProcessInterrupts+0x2530d fffff80a`1ecae623 : ffffb00e`0c4226b0 00000001`00000000 00000001`00000000 00000000`00000000 : e1i63x64!INTERRUPT::MsgIntDpcTxRxProcessing+0x1210e fffff80a`1ecaddb8 : ffffb00e`0e66f7d8 00000000`00000000 40200342`00000000 00000000`00000000 : e1i63x64!INTERRUPT::MsgIntMessageInterruptDPC+0x10f0f fffff80a`1e104e69 : ffffda01`9d7c9010 ffffda01`9d7c9320 00000000`00000000 00000000`00000000 : e1i63x64!INTERRUPT::MiniportMessageInterruptDPC+0x2810 fffff803`92e7f785 : ffffb00e`0d200000 fffff803`93155180 ffffb00e`0cc8e5d0 ffffb00e`0cc8e5d0 : NDIS!ndisInterruptDpc+0x1c911 fffff803`92e7ed10 : fffff80a`20dc79a8 00000000`002e593c 00000000`00140001 00000000`00000000 : nt!KiExecuteAllDpcs+0x33512 fffff803`92f7500a : 00000000`00000000 fffff803`93155180 fffff803`931d1980 ffffb00e`0f6cc080 : nt!KiRetireDpcList+0x91013 00000000`00000000 : fffff803`94d7c000 fffff803`94d76000 00000000`00000000 00000000`00000000 : nt!KiIdleLoop+0x5a
tcpip.sys 在使用IppReceiveHeaderBatch 函数处理接收到的数据包的同时，对 next header 的数值进行判断并调用相应函数处理对应头部，然后处理 fragment header ，漏洞发生在这个部位。
tcpip.sys 调用 Ipv6pReceiveFragmentList 函数对 fragment header 进行处理，然后对分片头进行重组
void Ipv6pReassembleDatagram(__int64 Packet, Reassembly_t *Reassembly, char OldIrql){ExtensionHeaderLength = Reassembly->ExtensionHeaderLength;TotalLength = ExtensionHeaderLength + Reassembly->DataLength;HeaderAndOptionsLength = ExtensionHeaderLength + 0x28;NetBufferList = NetioAllocateAndReferenceNetBufferAndNetBufferList(IppReassemblyNetBufferListsComplete,Reassembly,0i64,0i64,0,0);NetBuffer = NetBufferList->FirstNetBuffer;data = NdisGetDataBuffer(NetBuffer, HeaderAndOptionsLength, 0i64, 1u, 0) // 请求访问 NET_BUFFER 中的一段连续空间，请求的大小为 HeaderAndOptionsLengthReassembly->IPv6.Payload_length = __ROR2__(TotalLength, 8);*data = Reassembly->IPv6; // 复制 IPv6 headermemmove(data + 0x28, Reassembly->ExtensionHeader, Reassembly->ExtensionHeaderLength); // 复制 ExtensionHeader*(data + Reassembly->nh_offset) = Reassembly->next_header; // 复制 next header...}
缓冲区 data 的大小为 HeaderAndOptionsLength，next header 的偏移值为 Reassembly->nh_offset。发生越界写的原因就是 Reassembly->nh_offset 的数值大于 HeaderAndOptionsLength。
接下来通过调试确定这两个数值的来源，测试用数据包组成如下：
0 1 2 3 4 5 6 7 8 9 a b c d e f+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+0000 | Ethernet II, 0x0e B | |+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ +0010 | |+ IPv6 header, 0x28 B +0020 | |+ +--+--+--+--+--+--+--+--+--+--+0030 | | Routing header, 8 B |93 59 -> ESP header, 8 B+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+0040 99 40 00 00 00 00|55 55 55 55 55 55 55 55 55 55 -> IV, 0x10 B+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+0050 55 55 55 55 55 55|eb 42 e4 0a 95 da 11 1d 21 a1| -> payload + padding + padding_length + next_header+--+--+--+--+--+--+ + 0x30 B，已被加密0060 |ea c7 31 c9 e1 24 48 8d f9 98 d4 98 82 b7 eb 5d|+ +0070 |b7 8f bf c6 3a 00 eb 22 7d 26 55 b7 43 9f 60 62|+ +--+--+--+--+--+--+--+--+--+--+0080 |e3 ea fe 8c 23 87|+--+--+--+--+--+--+
然后对其进行解密，得到
0x00 -- -- -- -- -- -- 3a 00-00 01 56 56 56 56 55 550x10 55 55 55 55 55 55 55 55-55 55 55 55 55 55 55 550x20 55 55 55 55 55 55 01 02-03 04 05 06 07 08 09 0a0x30 0b 0c 0d 0e 0e 2c
next header 字段的数值为 0x2c，即 Fragment Header for IPv6，进行调试
Packet->prefix_size = header_size;Packet->nh_offset = Packet->prefix_size;NetBufferList = Packet->net_buffer_list;routing_header = NdisGetDataBuffer(NetBufferList->FirstNetBuffer, 8u, &Storage, 1u, 0);len = 8 * routing_header->length + 8;Packet->prefix_size += len;Packet->nh_offset = Packet->prefix_size + LOWORD(NetBuffer->DataOffset) - data_offset + 9;Packet->prefix_size += (iv_length + 8);Packet->prefix_size += 8;ExtensionHeaderLength = Packet->prefix_size - 0x30;Reassembly->ExtensionHeaderLength = ExtensionHeaderLength;Reassembly->nh_offset = Packet->nh_offset;
|<- data buffer size ->||<- 0x28 B ->|<- Extension Header 0x20 B ->|+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+| IPv6 header | Routing header | ESP header | IV | Payload |PL |NH |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
original packet:+-----------------+-----------------+--------+--------+-//-+--------+| Per-Fragment |Ext & Upper-Layer| first | second | | last || Headers | Headers |fragment|fragment|....|fragment|+-----------------+-----------------+--------+--------+-//-+--------+fragment packets:+------------------+---------+-------------------+----------+| Per-Fragment |Fragment | Ext & Upper-Layer | first || Headers | Header | Headers | fragment |+------------------+---------+-------------------+----------++------------------+--------+-------------------------------+| Per-Fragment |Fragment| second || Headers | Header | fragment |+------------------+--------+-------------------------------+ooo+------------------+--------+----------+| Per-Fragment |Fragment| last || Headers | Header | fragment |+------------------+--------+----------+
0x04 漏洞范围
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所有运行IPSEC的IPV6 windows设备
0x05 漏洞信息
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漏洞名称：Windows TCP/IP 远程命令执行漏洞
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漏洞编号：CVE-2022-34718
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漏洞危害：严重 远程命令执行
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漏洞poc：已知
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漏洞exp：暂无
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在野利用：存在
ps：网传exp疑似存在投毒嫌疑，请注意辨别
0x06 漏洞修复
官方已发布修复方案，请更新Windows系统至最新版本
原文始发于微信公众号（火山信安实验室）：【漏洞通报】Windows TCP/IP 存在远程命令执行漏洞（CVE-2022-34718）
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