Malicious PDF — malware analysis report

Static analysis result for SHA-256 c1a8fcbe86240257…

MALICIOUS

PDF

87.4 KB Created: 2021-08-06 00:44:47 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: 93cedaab9af0466ea8df84fadc881139 SHA-1: 8551c541d897ac590348b5e387e2dd334790bd3c SHA-256: c1a8fcbe86240257fcb0581a23b2dbd469d53c7abdc44042861c9f846a7968f0
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF file was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. It contains numerous links, many pointing to compromised CMS upload directories or disposable hosting, suggesting a link farm designed to redirect users to malicious sites. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, indicating it's not intended for direct user reading but rather as a container for these malicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9990

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • PDF link farm points to compromised-WordPress upload storage medium PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM
    PDF contains multiple clickable links, across many distinct hosts, whose targets are random-slug files parked in the upload directories of vulnerable WordPress form plugins (FormCraft, Super Forms). This is the hallmark of the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains hosted on compromised sites. The PDF itself carries no exploit — the risk is the linked destinations.
  • Small PDF is a non-clustered link farm on disposable hosting medium PDF_SEO_DISPOSABLE_LINK_FARM
    Small PDF contains many clickable external PDF links spread thin across many distinct hosts (no single dominant host), corroborated by a utm_term SEO-redirector link and/or links parked on free/disposable content hosts. This is the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains, rather than a normal document citation pattern. The PDF itself carries no exploit — the risk is the linked destinations.
  • External URI info PDF_URI
    PDF contains an external URL action
  • Object number defined twice with different bodies info PDF_DUPLICATE_OBJ_BODY_INCREMENTAL
    The same indirect object (N G) is defined more than once with different body bytes. First-wins and last-wins readers will resolve different content, which is a parser-confusion shape used by targeted PDFs. Body-only differences are common in benign incremental updates, so severity is raised only when the duplicate carries active content.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://sdds.be/userfiles/file/zibolobogo.pdf In PDF document text
    • http://bakkervoorwinde.nl/app/webroot/files/ckeditor_files/files/zijekoresapulisirojun.pdfIn PDF document text
    • http://vistobrasil.net/uploads/file/zuxidodofazuginuzon.pdfIn PDF document text
    • http://themultifold.com/wp-content/plugins/super-forms/uploads/php/files/3m54kb60rmgmenp18qoti49171/temebozefudujomofavu.pdfIn PDF document text
    • https://shiokerbau1.com/contents//files/detoxoromide.pdfIn PDF document text
    • http://www.tecnotrefg.it/wp-content/plugins/formcraft/file-upload/server/content/files/1608b0665688aa---dagofubotejurinirezebat.pdfIn PDF document text
    • https://action-roofing.com/wp-content/plugins/super-forms/uploads/php/files/bf1d8cb1a77ce95dab07c5f2b2b40d9b/15416499569.pdfIn PDF document text
    • https://anmoul.com/userfiles/file/86796873812.pdfIn PDF document text
    • https://kuechentreff-schmid.de/wp-content/plugins/super-forms/uploads/php/files/a48auin30c1vjd0s32cat1onoo/zipaxuxip.pdfIn PDF document text
    • https://flylights.pl/wp-content/plugins/super-forms/uploads/php/files/q9c5eb0v76sj2g0661vqnugs2t/93956414924.pdfIn PDF document text
    • http://www.jesuseslaroca.org/wp-content/plugins/formcraft/file-upload/server/content/files/16086554a379aa---59526681548.pdfIn PDF document text
    • http://virtuozi.ru/sites/all/sites/virtuozi.ru/files/pobidifenofi.pdfIn PDF document text
    • https://cokhivietuc.com/img-vietuc/files/fujezubijizukevuragaliw.pdfIn PDF document text
    • http://keacg.com/upload/files/lasufepodi.pdfIn PDF document text
    • https://marciasmithconsulting.com/wp-content/plugins/super-forms/uploads/php/files/72ee67d4474687d6bcaf49a5ceb9813b/15210809431.pdfIn PDF document text
    • https://nuevocoach.co.uk/wp-content/plugins/super-forms/uploads/php/files/3d66828ef91da963e4451e840b8b5ed0/siwivagoruranuviwakipibu.pdfIn PDF document text
    • http://cepsagibyachtfuels.com/images/photos/pesaxat.pdfIn PDF document text
    • http://sandsflooring.co.uk/ckfinder/userfiles/files/benisopijadogikaxepipe.pdfIn PDF document text
    • https://www.revistadefiesta.com/wp-content/plugins/formcraft/file-upload/server/content/files/160d039174647e---14041081608.pdfIn PDF document text
    • http://juniorsmagazine.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609506b85f1d0---6728392828.pdfIn PDF document text
    • https://palcev.ru/userfiles/file/63768171208.pdfIn PDF document text
    • https://medicentrumnz.eu/medicentrum/files/file/punuta.pdfIn PDF document text
    • https://glosunspa.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c969ce22cd4---54854295901.pdfIn PDF document text
    • https://law.myvzl.com/wp-content/plugins/super-forms/uploads/php/files/kodgq0d4sa108gp2puprtush0m/46500416190.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/BkSY9tpko7c/uplcv?utm_term=best+selling+kancan+jeansPDF link annotation
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#In PDF document text
    • http://purl.org/dc/elements/1.1/In PDF document text
    • http://ns.adobe.com/pdf/1.3/In PDF document text
    • http://ns.adobe.com/xap/1.0/In PDF document text
    • http://ns.adobe.com/xap/1.0/mm/In PDF document text
    • http://ns.adobe.com/xap/1.0/rights/In PDF document text
    • http://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000f162.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF162 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off00010979.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10979 10460 bytes
SHA-256: 18eb7ca8f836b8ee408046a40d2a727967a94594d3362d08642f35598d662f15
font_02_sfnt_off00012153.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12153 17056 bytes
SHA-256: ae40eaf92dc8981e76399909a345c86ddfcd1dfef8bbd554fd533dbcdf313597