FLIE EXTENSION WINZIP WINRAR SAFE HOW TO
FLIE EXTENSION WINZIP WINRAR SAFE DRIVER

To cut a long story short, Dave didn’t just figure out a vulnerability that was theoretically exploitable, he also created a proof-of-concept (PoC) exploit that showed how to create a RAR file that, when opened, would sneakily and unexpectedy launch the Calculator app. No download dialogs, no pop-up warnings, no “Are you sure?” prompts.

Remote code executionĬode that sneaks in by masqeurading as data is known as shellcode.īugs that allow shellcode to be executed are known as remote code execution vulnerabilities (RCEs), because a crook can use a malicious file, sent in from outside, to run malware on your computer even if all you do is to open the booby-trapped file and look at it. Simply put, a raft of uninitialised variables in the UnRAR code opened the door to the possibility of creating a booby-trapped archive file that would trick the UnRAR code into executing code hidden in the data part of the booby-trapped file.

FLIE EXTENSION WINZIP WINRAR SAFE DRIVER

That’s a bit like a car rental company hiring out its vehicles in a completely unknown condition each time, relying instead on every driver doing a full and complete check of their own, and correctly fixing any faults, before driving off. What Dave discovered is that the UnRAR decompression code, as used by 7-Zip, didn’t bother to configure itself safely when you started using it – in other words, your software could innocently lead to a catastrophic failure in the RAR code itself. When you have many small but similar files in an archive, for example, this often results in many more repeated string matches being found, thus boosting the compression ratio. The RAR file format includes this so-called solid option because it can improve compression by allowing repeated strings of characters to be matched even if they’re in two or more different files, instead of restricting all repeated data fragments to one file. The UnRAR code is complex because it supports many different varieties of compression level and format, including a special sort of compression system that strings multiple files together before compressing them, which often squeezes more bytes out of the compressed data than squashing each file independently. Now that 7-Zip has been patched against this bug, dubbed CVE-2018-10115, LANDAVE has published the details of how he found it, and what was involved in figuring out how severe the bug might be.Īccording to Dave, the problem arose from an all-too-common conflict between complexity and security.

Flie extension winzip winrar safe