A .WAV With A Payload, (Tue, Apr 21st)
好的,我现在需要帮用户总结一篇关于恶意软件使用.wav文件作为传播载体的文章。用户要求控制在100字以内,直接描述内容,不需要特定的开头。 首先,我需要通读文章,抓住关键点。文章提到威胁行为者使用.wav文件作为恶意软件的传播媒介,但并未使用隐写术。.wav文件播放时会发出噪音,因为声音编码的字节被替换为Base64编码的payload。作者展示了如何用base64dump.py提取payload,并通过XOR解码得到PE文件。最后,用pecheck.py分析样本。 接下来,我需要将这些信息浓缩到100字以内。要确保涵盖主要步骤:wav文件作为载体、Base64编码、XOR解码、工具使用以及最终分析结果。 可能的结构是:威胁行为者利用.wav文件传播恶意软件,未使用隐写术;声音被Base64 payload替换;通过工具提取并解码得到PE文件;最终分析样本。 现在检查字数是否符合要求,并确保信息准确无误。 </think> 威胁行为者利用.wav文件传播恶意软件,未使用隐写术。声音编码被替换为Base64 payload,播放时为噪音。通过base64dump.py提取payload,并用xor-kpa.py解码XOR加密的PE文件。最终提取并分析样本。 2026-4-21 07:14:56 Author: isc.sans.edu(查看原文) 阅读量:8 收藏

There have been reports of threat actors using a .wav file as a vector for malware.

It's a proper .wav file, but they didn't use staganography. The .wav file will play, but you'll just hear noise:

That's because the TAs have just replaced the bytes that encode the sound with the BASE64 representation of their payload:

Thus I don't need a .wav parser to extract the encoded payload, I can just use my base64dump.py tool:

The BASE64-decoded payload is an XOR-encoded PE file. So I don't need to make a custom decoder, I can just perform a known-plaintext attack looking for the DOS header with my xor-kpa.py tool:

The XOR key was found. Thus we can easily dump the decoded PE file and see the MZ header at position 0x08 and a bit further down the DOS header we used in the known-plaintext-attack:

And my tool pecheck.py can extract an analyse the sample:

Didier Stevens
Senior handler
blog.DidierStevens.com


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