HC7 GOTYA Ransomware Installed via Remote Desktop Services. Spread with PsExec

[LASER_oneXM]

A new ransomware called HC7 is infecting victims by hacking into Windows computers that are running publicly accessible Remote Desktop services. Once the developers gain access to the hacked computer, the HC7 ransomware is then installed on all accessible computers on the network.

Originally released as HC6, victims began posting about it in the BleepingComputer forums towards the end of November. As this is a Python-to-exe executable, once the script was extracted ID Ransomware creator Michael Gillespie was able determine that it was decryptable and released a decryptor.

Unfortunately, a few days later, the ransomware developers released a new version called HC7 that was not decryptable. Thi sis because they removed the hard coded encryption key and instead switched to inputting the key as a command line argument when the attackers run the ransomware executable. Thankfully, there may be a way to get around that as well so that victims can recover their keys.

Attackers spreading HC7 Ransomware in network using PsExec
Currently the attackers are hacking into exposed remote desktop services, and once inside, use PsExec to install the ransomware on other computers in the network. The use of PsExec is evident in the source code below, which specifically looks for the PsExec.exe and skips it from being encrypted.

Finding Files to Encrypt Source Code
As previously stated, when the attacker executes the ransomware they will provide the encryption key as a command line argument. This key is then used to encrypt files that match the following extensions with AES-256 encryption.

.001, .3fr, .3gp, .7z, .ARC, .DOT, .MYD, .MYI, .NEF, .PAQ, .SQLITE3, .SQLITEDB, .accdb, .aes, .ai, .apk, .arch00, .arw, .asc, .asf, .asm, .asp, .asset, .avi, .bar, .bay, .bc6, .bc7, .big, .bik, .biz, .bkf, .bkp, .blob, .bmp, .brd, .bsa, .cas, .cdr, .cer, .cfr, .cgm, .class, .cmd, .cpp, .cr2, .crt, .crw, .csr, .css, .csv, .d3dbsp, .das, .dazip, .db0, .dbf, .dbfv, .dch, .dcr, .der, .desc, .dif, .dip, .djv, .djvu, .dmp, .dng, .doc, .docb, .docm, .docx, .dotm, .dotx, .dwg, .dxg, .epk, .eps, .erf, .esm, .exe, .ff, .fla, .flv, .forge, .fos, .fpk, .frm, .fsh, .gdb, .gho, .gpg, .hkdb, .hkx, .hplg, .htm, .html, .hvpl, .hwp, .ibank, .ibd, .icxs, .indd, .itdb, .itl, .itm, .iwd, .iwi, .jar, .java, .jpeg, .jpg, .js, .kdb, .kdc, .key, .kf, .lay, .lay6, .layout, .lbf, .ldf, .litemod, .log, .lrf, .ltx, .lvl, .m2, .m3u, .m4a, .map, .max, .mcgame, .mcmeta, .mdb, .mdbackup, .mddata, .mdf, .mef, .menu, .mid, .mkv, .mlx, .mml, .mov, .mp3, .mpeg, .mpg, .mpqge, .mrwref, .ms11 (Security copy), .ncf, .nrw, .ntl, .ocx, .odb, .odc, .odm, .odp, .ods, .odt, .orf, .otg, .ots, .ott, .p12, .p7b, .p7c, .pak, .pas, .pdd, .pdf, .pef, .pem, .pfx, .php, .pkpass, .pl, .png, .ppam, .ppsm, .ppsx, .ppt, .pptm, .pptx, .psd, .psk, .pst, .ptx, .py, .qcow2, .qdf, .qic, .r3d, .raf, .rar, .raw, .rb, .re4, .rgss3a, .rim, .rofl, .rtf, .rw2, .rwl, .sav, .sb, .sc2save, .sch, .sid, .sidd, .sidn, .sie, .sis, .sldm, .sldx, .slk, .slm, .snx, .sql, .sr2, .srf, .srt, .srw, .stc, .stw, .sum, .svg, .swf, .sxc, .sxm, .sxw, .syncdb, .t12, .t13, .tar, .tar.bz2, .tar.gz, .tax, .tbk, .tgz, .tif, .tiff, .tor, .txt, .unity3d, .uot, .upk, .upx, .vbs, .vdf, .vdi, .vfs0, .vmdk, .vmx, .vob, .vpk, .vpp_pc, .vtf, .w3x, .wav, .wb2, .wma, .wmo, .wmv, .wotreplay, .wpd, .wps, .x3f, .xf, .xlc, .xlk, .xlm, .xls, .xlsb, .xlsm, .xlsx, .xlt, .xlw, .xml, .xxx, .zip, .ztmp, wallet.dat

When the ransomware encrypts a file it will append the .GOTYA extension on the encrypted file's name. For example, the file test.jpg would be encrypted and renamed to test.jpg.GOTYA.

Encrypted Folder of Encrypted GOTYA Files
While encrypting a computer, the ransomware will create a ransom note named RECOVERY.txt in each folder that a file was encrypted. This ransom note will contain a bitcoin address, a victim ID, payment instructions, and an email address that the victim can use to contact the ransomware developer. This email address is m4zn0v@keemail.me. Currently, the ransom demands are $700 in BTC for one machine or $5,000 in BTC for all the infected computers on the network.

 

[Deleted member 65228]

PsExec is genuine and from SysInternals but it is sad how it can be easily abused to cause lots of harm.