.net # 检查 带有pdf xss

1.解决pdf含javasprct脚本动作，这里是验证pdf内部事件。相关pdf文件下载：
测试pdf文件

相关包 iTextSharp 5.5.13.4
iTextSharp

using iTextSharp.text.pdf;
using iTextSharp.text.pdf.parser;private Boolean IsPdfSafe(Stream stream){//  PdfReader reader = new PdfReader(stream);using (PdfReader reader = new PdfReader(stream)){for (int i = 1; i <= reader.NumberOfPages; i++){PdfDictionary pageDic = reader.GetPageN(i);PdfObject obj = PdfReader.GetPdfObject(pageDic.Get(PdfName.ANNOTS));if (obj == null || !obj.IsArray())continue;PdfArray annots = (PdfArray)obj;for (int j = 0; j < annots.Size; j++){PdfDictionary annot = annots.GetAsDict(j);PdfName subtype = annot.GetAsName(PdfName.SUBTYPE);if (PdfName.LINK.Equals(subtype)){PdfDictionary actionDict = annot.GetAsDict(PdfName.A);if (actionDict != null){PdfObject action = actionDict.Get(PdfName.S);if (action != null){//可以判断具体哪些事件被拦截，目前已知事件GOTO,URI（连接跳转）Console.WriteLine("Action found: " + action.ToString());return false;}}}}}}return true;}

//应用的地方 写入缓存比较好，因为是非报错判断成功后可进行保存

   using (MemoryStream memoryStream = new MemoryStream(buffer)){if (!IsPdfSafe(memoryStream)){//TODO 返回错误信息}}

以上就是判断脚本的相关代码。

2.下面介绍一下读取pdf内容的脚本内容，仅做参考。

 for (int i = 1; i <= reader.NumberOfPages; i++){PdfDictionary pageDict = reader.GetPageN(i);PdfDictionary resourcesDict = pageDict.GetAsDict(PdfName.RESOURCES);//     PdfDictionary ACTION = resourcesDict.GetAsDict(PdfName.ACTION);//      PdfDictionary actionDict = javascriptDict.GetAsDict(PdfName.JAVASCRIPT);if (resourcesDict != null){PdfDictionary javascriptDict = resourcesDict.GetAsDict(PdfName.JS);if (javascriptDict != null){PdfDictionary actionDict = javascriptDict.GetAsDict(PdfName.JAVASCRIPT);if (actionDict != null){return false;}}}}

除了上面的iTextSharp ，还有itext7也是做pdf相关处理的。iTextSharp 已经停止更新两年了，如果要开发建议用itext7,上述代码进攻参考，因为版本不一样，调用接口也会不一样，开发时候请查相关api具体内容。

代码地址：https://github.com/itext/itextsharp
api地址：https://api.itextpdf.com/iText/dotnet/

3.如何制作带脚本pdf ,请参考下面博文。
https://blog.csdn.net/weixin_50464560/article/details/123841755?ops_request_misc=%257B%2522request%255Fid%2522%253A%2522172259109316800188565451%2522%252C%2522scm%2522%253A%252220140713.130102334.pc%255Fblog.%2522%257D&request_id=172259109316800188565451&biz_id=0&utm_medium=distribute.pc_search_result.none-task-blog-2_blogfirst_rank_ecpm_v1~rank_v31_ecpm-5-123841755-null-null.nonecase&utm_term=pdf%20xss&spm=1018.2226.3001.4450