Last week a new ransomware called Coverton was released that uses AES+RSA encryption to ransom your files for 1 bitcoins. Unfortunately, analysis has shown that this ransomware is cryptographically sound, which means that there are no underlying weakness that can be exploited to decrypt the files for free. Due to this, some victims have resorted to paying the ransom. After receiving the decryptor, though, victim's have learned that it is not properly decrypting their files.

Coverton Decryptor
Coverton Decryptor

Reports from two victim's indicate that the decryptor being sent by the Coveton crew is either not decrypting properly or the original data was encrypted poorly.  Either way you look at it, its frustrating enough to hear that a victim pays the ransom, but even worse when we discover that it doesn't help them. 

For those who are infected with the Coverton Ransomware, you may want to seriously reconsider if you plan on paying this ransom as you may be just throwing your money away. For those who want a bit more technical info about this ransomware, you can see the section below. For those who wish to discuss this ransomware or receive help, you can use the Coverton Ransomware Infection Support and Help Topic.

The Coverton Ransomware Family

The Coverton ransomware was first spotted on March 23rd, 2016 and it is currently unknown how the ransomware is being distributed. Once installed, it will copy itself to %UserProfile%\userlog.exe and configure an autorun so it starts automatically when Windows starts. It will then scan your computer for files that contain certain extensions and encrypt them using AES encryption. Depending on which variant of the Coverton ransomware you are infected with, the encrypted files will have  the .coverton, .enigma, or .czvxce extensions appended to the file. So for example, test.jpg would become test.jpg.coverton, or test.jpg.enigma, or test.jpg.czvxce.

The targeted file extensions are:

1cd, 1st, 2bp, 3dm, 3ds, 3fr, 4db, 4dl, 4mp, 73i, 7z, 7z001, 7z002, 8xi, 9png, a00, a01, a02, a3d, abm, abs, abw, accdb, accdc, accde, accdr, accdt, accdw, accft, ace, act, adn, adp, af2, af3, aft, afx, agg, agif, agp, ahd, ai, aic, aim, ain, albm, alf, alz, ani, ans, apd, apm, apng, aps, apt, apx, apz, ar, arc, arh, ari, arj, ark, art, artwork, arw, asc, ascii, ase, ask, asp, aspx, asw, asy, aty, avatar, awdb, awp, awt, aww, axx, azz, b1, b64, ba, backup, bad, bak, bay, bbs, bdb, bdp, bdr, bean, bh, bhx, bib, blend, blkrt, bm2, bmp, bmx, bmz, bna, bnd, bndl, boc, bok, boo, brk, brn, brt, bss, btd, bti, btr, bz, bz2, bza, bzabw, bzip, bzip2, c00, c01, c02, c10, c4, c4d, cal, cals, can, car, cb7, cba, cbr, cbz, cd5, cdb, cdc, cdg, cdmm, cdmt, cdmtz, cdmz, cdr, cdr3, cdr4, cdr6, cdrw, cdt, cdz, cf, cfu, cgm, chart, chord, cimg, cin, cit, ckp, clkw, cma, cmx, cnm, cnv, colz, cp9, cpc, cpd, cpg, cps, cpt, cpx, cr2, crd, crwl, css, csv, csy, ct, cv5, cvg, cvi, cvs, cvx, cwt, cxf, cyi, czip, daconnections, dacpac, dad, dadiagrams, daf, daschema, db, db2, db3, dbc, dbf, dbk, dbs, dbt, dbv, dbx, dc2, dca, dcb, dcr, dcs, dct, dcx, dd, ddl, ddoc, dds, deb, ded, design, df1, dgc, dgn, dgs, dgt, dhs, dib, dicom, dist, diz, djv, djvu, dm3, dmi, dmo, dnc, dne, doc, docm, docx, docxml, docz, dot, dotm, dotx, dp1, dpp, dpx, dqy, drw, drz, dsk, dsn, dsv, dt, dt2, dta, dtsx, dtw, dvi, dvl, dwg, dx, dxb, dxf, dxl, dz, eco, ecs, ecw, ecx, edb, efd, efw, egc, eio, eip, eit, email, emd, emf, emlx, ep, epf, epi, epp, eps, epsf, eql, erf, err, etf, etx, euc, exr, f, fadein, fal, faq, fax, fb2, fb3, fbl, fbx, fcd, fcf, fdb, fdf, fdp, fdr, fds, fdt, fdx, fdxt, fes, fft, fh10, fh11, fh3, fh4, fh5, fh6, fh7, fh8, fic, fid, fif, fig, fil, flc, fli, flr, fm5, fmp, fmp12, fmpsl, fmv, fodt, fol, fountain, fp3, fp4, fp5, fp7, fp8, fpos, fpt, fpx, frt, ft10, ft11, ft7, ft8, ft9, ftn, fwdn, fxc, fxg, fzb, fzv, g3, gca, gcdp, gdb, gdoc, gdraw, gem, geo, gfb, gfie, ggr, gif, gih, gim, gio, glox, gmbck, gmspr, gmz, gpd, gpn, gro, grob, grs, gsd, gthr, gtp, gv, gwi, gz, gz2, gza, gzi, gzip, ha, hbc, hbc2, hbe, hbk, hdb, hdp, hdr, hht, his, hki, hki1, hki2, hpg, hpgl, hpi, hpl, hs, htc, html, hwp, hz, i3d, ib, icn, icon, icpr, idc, idea, idx, igt, igx, ihx, iil, iiq, imd, info, ink, int, ipf, ipx, itc2, itdb, itw, iwi, j, j2c, j2k, jarvis, jas, jb2, jbig, jbig2, jbmp, jbr, jfif, jia, jis, jng, joe, jp1, jp2, jpe, jpeg, jpg, jpg2, jps, jpx, jrtf, jtf, jtx, jwl, jxr, kdb, kdbx, kdc, kdi, kdk, kes, kic, klg, knt, kon, kpg, kwd, latex, lbm, lbt, lgc, lis, lit, ljp, lmk, lnt, lp2, lrc, lst, ltr, ltx, lue, luf, lwo, lwp, lws, lxfml, lyt, lyx, m3d, ma, mac, maf, man, map, maq, mat, max, mb, mbm, mbox, md5txt, mdb, mdbhtml, mdf, mdn, mdt, me, mef, mell, mft, mgcb, mgmf, mgmt, mgmx, mgtx, mhtml, min, mmat, mng, mnr, mnt, mobi, mos, mpf, mpo, mrg, mrxs, msg, mt9, mud, mwb, mwp, mxl, myd, myl, ncr, nct, ndf, nfo, njx, nlm, notes, now, nrw, ns2, ns3, ns4, nsf, nv2, nwctxt, nyf, nzb, obj, oc3, oc4, oc5, oce, oci, ocr, odb, odm, odo, ods, odt, ofl, oft, omf, openbsd, oplc, oqy, ora, orf, ort, orx, ota, otg, oti, ott, ovp, ovr, owc, owg, oyx, ozb, ozj, ozt, p7s, p96, p97, pages, pal, pan, pano, pap, pbm, pc1, pc2, pc3, pcd, pcs, pcx, pdb, pdd, pdf, pdm, pdn, pe4, pef, pfd, pff, pfi, pfs, pfv, pfx, pgf, pgm, phm, php, pi1, pi2, pi3, pic, pict, pix, pjpeg, pjpg, pjt, pl, plantuml, plt, pm, pmg, png, pni, pnm, pntg, pnz, pobj, pop, pp4, pp5, ppm, ppt, pptm, pptx, prt, prw, ps, psd, psdx, pse, psid, psp, pspbrush, psw, ptg, pth, ptx, pu, pvj, pvm, pvr, pwa, pwi, pwr, px, pxr, pz3, pza, pzp, pzs, qdl, qmg, qpx, qry, qvd, ras, raw, rctd, rcu, rdb, rdl, readme, rft, rgb, rgf, rib, ric, riff, ris, rix, rle, rli, rng, rpd, rpf, rpt, rri, rs, rsb, rsd, rsr, rst, rt, rtd, rtf, rtx, run, rw2, rwl, rzk, rzn, s2mv, s3m, saf, safetext, sai, sam, save, sbf, scad, scc, sci, scm, scriv, scrivx, sct, scv, scw, sdb, sdf, sdm, sdoc, sdw, sep, sfc, sfera, sfw, sgm, sig, sk1, sk2, skcard, skm, sla, slagz, sld, sldasm, slddrt, sldprt, sls, smf, smil, sms, snagitstamps, snagstyles, sob, spa, spe, sph, spj, spp, spq, spr, sqb, sql, sqlite, sqlite3, sqlitedb, sr2, srw, ssa, ssfn, ssk, st, ste, stm, stn, stp, str, strings, stw, sty, sub, sumo, sva, svf, svg, svgz, swf, sxd, sxg, sxw, t2b, tab, tb0, tbn, tcx, tdf, tdt, te, teacher, tex, text, tfc, tg4, tga, thm, thp, thumb, tif, tiff, tjp, tlb, tlc, tm, tm2, tmd, tmv, tmx, tn, tne, tpc, tpi, trelby, trm, tvj, txt, u3d, u3i, udb, ufo, ufr, uga, unauth, unity, unx, uof, uot, upd, usr, utf8, utxt, v12, vault, vbr, vct, vda, vdb, vec, vff, vml, vnt, vpd, vpe, vrml, vrp, vsd, vsdm, vsdx, vsm, vst, vstm, vstx, vue, vw, wb1, wbc, wbd, wbk, wbm, wbmp, wbz, wcf, wdb, wdp, webdoc, webp, wgz, wire, wlmp, wmdb, wmf, wn, wp, wp4, wp5, wp6, wp7, wpa, wpb, wpd, wpe, wpg, wpl, wps, wpt, wpw, wri, wsc, wsd, wsh, wtx, wvl, x, x3d, x3f, xar, xbdoc, xbplate, xdb, xdl, xhtml, xld, xlf, xlgc, xls, xlsm, xlsx, xmind, xmmap, xpm, xps, xwp, xy3, xyp, xyw, y, yal, ybk, yml, ysp, z3d, zabw, zdb, zdc, zif, zw, 

When encrypting files, Coverton will also create a ransom note called !!!-WARNING-!!!.html and !!!-WARNING-!!!.txt in each folder that a file has been encrypted. These ransom notes provide instructions on how to access the ransomware's TOR decryption site and make a payment. An example ransom note is shown below.

HTML Coverton Ransom Note
HTML Coverton Ransom Note

Coverton will also delete the shadow volume copies on the victim's machine so that they cannot be used to restore the unencrypted files. Finally, the ransomware will send information such as when the ransomware started, when the encryption phase started, when it ended, the amount of files encrypted, the total size of encrypted files, and other information to the Command & Control server. This information will then be used by the TOR payment site when displaying your statistics.

The Coverton Decryptor Site

The TOR payment site for Coverton is called Corveton Decryptor.  On this site a victim will see information such as the amount and the total size of the encrypted files. Each victim will also be given their own unique bitcoin address that can be used to send a 1 bitcoin payment.

Coverton Decryptor Site
Coverton Decryptor Site

Once a payment has been made and there have been enough confirmations on the bitcoin transaction, this will page will then display a download link for the decryptor.  As already stated, there have been reports that this decryptor does not properly decrypt all of the encrypted files. Therefore, only pay the ransom if you are willing to take that risk.

 

Files associated with the Coverton Ransomware Family

%UserProfile%\userlog.exe
%UserProfile%\Desktop\!!!-WARNING-!!!.html
%UserProfile%\Desktop\!!!-WARNING-!!!.txt
%UserProfile%\Desktop\old

Registry entries associated with the Coverton Ransomware Family

HKCU\Software\Microsoft\Windows\CurrentVersion\Run\userlog	%UserProfile%\userlog.exe