Yes.7z ⇒ [ BEST ]

A "yes.7z" report generally refers to an investigation into a in 7-Zip (initially misreported as a "zero-day") involving the -y (assume "Yes" to all queries) command-line switch or its relation to arbitrary code execution through malicious 7z archives. Summary of the Investigation

In command-line usage, -y is a switch that forces 7-Zip to assume a "Yes" response to all interactive queries (such as "Overwrite existing file?") [0.34, 0.36]. While intended for silent automation, it can be abused in scripts to bypass user confirmation for malicious file overwrites. yes.7z

The issue often stems from the Zstandard (ZSTD) decoding routine or the LZMA decoder . Specifically, a signed variable could be converted to unsigned without proper bounds checking, leading to memory overwrites beyond allocated buffers. A "yes

Investigations confirmed that crafted .7z archives could cause crashes in functions like copy_chunks due to integer wrap-around . In theory, this allows an attacker to execute shellcode (e.g., launching calc.exe ) if a user opens a malicious archive. Technical Findings & Mitigations Risk Detail Mitigation Zstandard Decoding Buffer overflow in FSE decode sequence table . Update to 7-Zip version 24.07 or later . Command Line -y switch bypasses overwrite warnings. Avoid running unknown scripts with silent switches. Official Sources Fake sites like 7zip.com serve malware. Only download from 7-zip.org. Potential "Long Path" Issues Fake 7-Zip downloads are turning home PCs into proxy nodes The issue often stems from the Zstandard (ZSTD)

Detailed reports, such as those analyzed by security researchers at i dove down the 7z rabbit hole , look into vulnerabilities where malformed archives could trigger buffer overflows during decompression.