This instruction is applied to the buffer in 4 byte blocks. Looking at this function, we are quickly able to identify a common decryption signature:Īs seen in this disassembly, the XOR decryption key is set to 0xf799b659. Reviewing the disassembly, we come across an interesting function at address 0x100001f30 which is referenced throughout the malware and passed an argument of a pointer to a byte array. This can indicate a number of things, most likely is some form of encryption or packing, but it is certainly unusual for a binary to contain no identifiable strings at all. This, alongside the lack of any of the usual objc_msgsend calls, or method name mangling, indicate that this malware was likely written in C or C++.Īs we continue, we notice there are no identified strings contained within the binary: As we move to the entry point of the application with Hopper, we find a stack canary being added: In the case of MacRansom, we quickly see that this malware variant does not use either of the above. This often makes it my goto disassembler for Mac applications. If you have never used Hopper before, it is a low cost disassembler with incredible support for Objective-C and Swift binaries. Seeing how uncommon this type of “MaaS” is on MacOS (at the minute at least), this was a good opportunity to break out Hopper and see how well it handles malware analysis. If you are interested in the internals of the malware, I’d recommend that you take a look. Patrick from Objective-See does a brilliant fly-by of the malware using LLDB, and presents some nice “anti anti-analysis” tricks. This week, Objective-See published a walkthrough of the recently released “Malware as a Service” family, MacRansom, originally identified by FortiNet. Save the document with the filename " YOUR NAME Proj 7xb", replacing "YOUR NAME" with your real name.« Back to home Using Hopper scripting to analyse MacRansom So a simple way to make the program accept "Fail!", there is a comment beginning with In the right pane, to the right of the word got.plt section) pointers to library functions, which we have exploited in the past text section) More preparation to launch the program Pass 2: Segments, Sections, Symbols, & Strings Memory Layout Save the document with the filename " YOUR NAME Proj 7xa", replacing "YOUR NAME" with your real name. YOU MUST SUBMIT A FULL-SCREEN IMAGE FOR FULL CREDIT! Press the PrintScrn key to copy the whole desktop to the clipboard. The regions with a white background above Undefined (grey): an area not yet explored by Hopper.Procedure (yellow): Part of a method that has been successfully reconstructed by Hopper.ASCII (green): a NULL terminated C string.Data (purple): a constant, like an array of integers.One of these five categories, each coded with Comments: Added by Hopper to make the code easier to understand.In the Navigation bar, drag the little redĬode appears, with a yellow-shaded background The red arrow in the Navigation Bar is now Graph of the entire file, and the red arrow On the right edge, drag the scroll bar toīar with a little red arrow. Now, finally, the whole window is available Sudo apt install libqt5gui5 libqt5xml5 libqt5printsupport5 libqt5network5 libqt5core5a libqt5dbus5 libxcb-xinerama0 qtbase-abi-5-9-5 libqt5svg5 qt5-gtk-platformtheme libqt5core5a libqt5dbus5 qtbase-abi-5-9-5 libqt5core5a libqt5widgets5 qtbase-abi-5-9-5 libqt5core5a libqt5core5a libdouble-conversion1 qttranslations5-l10nĪ series of Assembly Language instructions.Īt the bottom, there is a pane containing And the free versionĪ 64-bit Ubuntu machine, real or virtual. Hopper is a disassembler and debugger that runs on Mac OS X or Linux,īut not Windows. Proj 7x: Introduction to Hopper (20 pts.) Proj 7x: Introduction to Hopper (20 pts.) Purpose
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