Retrieved August 24, 2020. Analyze the malware found in the file Lab09-02.exe using OllyDbg to answer the following questions. Allievi, A.,Flori, E. (2018, March 01). If you compare this to the event for CreateFile on the below, we can see that. It’s recommended a backup of the malware be created. Retrieved November 5, 2018. Close analysis reveals that this takes 2 chars which are then turned into a number, and then cross references that number to an index within the identified string. Highlighted in red are conditions that if evaluated will jump past the statement that sets EAX to 1. When abused by a malware author, this can prevent certain useful components such as the decompiler plugin, as this relies on having knowledge about the stack frame. If the program fails to get these instructions or it fails, it will display an error message. (2019, July). [46], InvisiMole can decrypt, unpack and load a DLL from its resources, or from blobs encrypted with Data Protection API, two-key triple DES, and variations of the XOR cipher. There’s a level of dependency between chunk size and Max Entropy when trying to find sections of interest within a binary. Retrieved August 9, 2018. Gamaredon Group has also decoded base64-encoded source code of a downloader. By examining sub_401651 (r) we can see that this has a call to ‘sub_401147’ to decode any provided URL, before calling ‘sub_401372’ which we identified in question 2 as being responsible for updating the C2 configuration file. NSA/FBI. This passes; however, at one point we will find ourself falling back into 0x402410 again due to a comparison that checks if more than 3 elements have been passed to the program (noting that the application name is passed as an argument). Looking at the only calling function to this, we can see that the argument passed to this is the established socket to the C2. Looking at the strings of this file shows 2 interesting elements, ‘malservice’ and ‘http://www.malwareanalysisbook.com’. Structures: Create own data structures or list layout of all data structures. Jazi, H. (2020, April 16). Function calls the ret instruction which pops return address off stack and onto EIP. What host-based or network-based indicators could be used to identify this malware on infected machines? Because the URL encoding uses a number mapping to a string previously identified: Because every URL is expected to be specified via ‘http://’ We simply need to determine what the encoded number value of ‘http://’ would be. By running the program in a sandbox we can see that after a brief period of time it opens a web browser to an advertisement located at: http://malwareanalysisbook.com/ad.html. By looking at this location within IDA, we can easily see that it is creating 5 different registry keys which goes completely undetected by Procmon. Analyze the malware found in the file Lab15-03.exe. [99], Skidmap has the ability to download, unpack, and decrypt tar.gz files . What is the content? Which two encoding techniques are used in this malware? [44], Honeybee drops a Word file containing a Base64-encoded file in it that is read, decoded, and dropped to the disk by the macro. Moving back from the call to sleep, we can see that EAX is multiplied by 1000 before being pushed to the stack and called. 346123. times. As a result a copy of this can be found here. New version of AZORult stealer improves loading features, spreads alongside ransomware in new campaign. In this instance we can see that there’s been some issues bringing back any capitalisation somewhere along the line and this should read “xdoor is this backdoor, string decoded for Practical Malware Analysis Lab :)1234”. Most common, the debugger performs this by overwriting the first byte of an instruction with 0xCC (Int 3) which is a breakpoint used by debuggers. If these do exist, it will print the message “Success: Parsed command is %c\n”, where %c is the first character read from the HTML comment buffer. Tartare, M. et al. Step-Into = Step into a sub-function/call and see the first instruction of called function. (2020, July 16). In this instance the base pointer contains our base64 encoded content and is then used within loc_401750 to concatenate our encoded content with the value ‘(!<’. Cmpsb takes byte at ESI, compares to value at EDI and increments ESI/EDI registers by 1. It will then startup again automatically and only seem like Windows has briefly refreshed. Only 4 hardware addresses store hardware breakpoints. (2018, November 20). By viewing the imports, searching for gethostbyname, and then looking for the address location, we find where this import is located. If we look at cross-references to this subroutine, we find is is called in another large routine at ‘sub_401082’. At ‘00409139’ and ‘0040915D’ we find some strings of interest if we convert them to ASCII using ‘A’. In this case we find that it is called within ‘sub_40132B’ which is started in a thread after cmd.exe has been run and our previous StartAddress call has run. How does Lab11-03.exe persistently install Lab11-03.dll? More than 30 types of conditional jumps exist, but only subset commonly seen. Generally after cmp, jumps if destination operand != source operand), jg loc (Jump if Greater. By renaming these functions and viewing the main method flow chart, we can easily see the flow of this malware. If the character sent is 14 higher than ‘d’ the switch case to run is 2. We know from previous analysis of this malware that configuration is stored in the registry so by default it communicates with: To analyse how this communication occurs and whether there’s any other network-based indicators we look back to sub_402020 and the function it calls prior to comparing the response received to one of the mentioned commands. By adding a breakpoint at this command and running the program we can see that it performs this XOR against a letter one by one, and in the first instance it XORs 46 and 31 (first letter of our key). Where this fails it will call ‘sub_401372’ which is used to create the file and write into it the contents of this hard-coded URL C2 before running itself again. Duncan, B. Based on the above we can see that these findings help us infer AES is likely being used when compared to performing a simple XOR check. [129][130], ZeroT shellcode decrypts and decompresses its RC4-encrypted payload. What is the difference between this lab’s parse HTML function and those of the previous labs? It subtracts value at EDI from ESI and updates the flags. [106][107][80], During execution, Threat Group-3390 malware deobfuscates and decompresses code that was encoded with Metasploit’s shikata_ga_nai encoder as well as compressed with LZNT1 compression. Used for pointing to a base (index) address within the data segment. First we take a look at Lab11-03.exe using IDA. What kind of information is communicated in the malware’s initial beacon? Does it match any existing antivirus definitions? Retrieved August 31, 2020. This occurs with an unusual user agent which is then followed by another request with an unusual user agent ‘Internet Surf’. By using the ‘-c’ argument we wind up once again with the malware attempting to remove itself. New targeted attack against Saudi Arabia Government. [75], PolyglotDuke can use a custom algorithm to decrypt strings used by the malware. mov edx, [eax] - Point to an entry at an offset of 0x88 (previous entry in list). With only these libraries it is a very good indication that this binary is packed. Gorelik, M.. (2019, June 10). using User32.dll) on a system making it difficult to fully remove if every user process is running the malware. From here we can see that the most common major function implemented is ‘nt!IopInvalidDeviceRequest’ which is basically a catch all for any function that this driver doesn’t implement. From this the switch uses reference to a table at byte_40173E to then look within an offset stored at ‘off_40172A’. This is the standard convention for the Windows API, and as such when calling them you don’t need to clean up the stack as the DLLs which implement the API will clean up the stack. In both of these calls the source of the URL is being passed to them, so we need to continue looking back to see how this is fetched. Sodin ransomware exploits Windows vulnerability and processor architecture. From the above we can see that when our subroutine at 0x401000 successfully finds winlogon.exe, it will call another at ‘sub_401174’. Threat Actor ITG08 Strikes Again. Sowbug: Cyber espionage group targets South American and Southeast Asian governments. At present the file is packed with FSG, and we are unable to unpack this with the techniques learnt so far. Examining the strings contained within Lab01-01.exe more closely reveals that it is referencing a file called C:\windows\system32\kerne132.dll. In Lab09-03.exe we can see that this calls and moves the output into ebp+hObject before passing it a buffer of the characters “malwareanalysisbook.com” to write. We can see this through the use of the Service Control (SC) binary. Pillowmint: FIN7’s Monkey Thief . By searching further within this function, we can see that a comparison occurs that checks if a file is a .exe, and if not a jump occurs. From here we can see that one of 2 paths will be taken depending on the result of sub_100036C3, so let’s dive a bit deeper there. Before getting into this chapter, we’ll need to setup a suitable environment for debugging Kernel Driver activity. [83], REvil can decode encrypted strings to enable execution of commands and payloads. In cases of push, there’ll be an additional instruction to restore the stack pointer which won’t be present in the move. [19], Bundlore has used openssl to decrypt AES encrypted payload data. Search a data buffer for a byte. What is happening in the area of code that references \cmd.exe /c? [121], WellMess can decode and decrypt data received from C2. Utilise a dedicated machine for research and hide location via cellular connection, tunnelling via SSH or VPN to remote infrastructure, and/or use a cloud service such as Amazon EC2. Analyze the malware found in file Lab14-02.exe. There are 2 types of disassembler algorithms. One issue we encounter here is that the malware is set to read a certain amount of characters from this resource section, so whatever IP address we choose to beacon to needs to be the same number of characters (9) as 127.0.0.1. Retrieved August 7, 2018. Falls ein Verkäufer in den USA oder Großbritannien ansässig ist, kann er das eBay-Programm zum weltweiten Versand (GSP) nutzen. At this time it will create 20 (14h) threads and with them execute the subroutine pointed to by ‘StartAddress’. (Hint: if isNAN(password string) is true, the password contains at least one byte that is NOT a digit; if false the password is composed of digits only).
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