Malicious PDF — malware analysis report

Static analysis result for SHA-256 51f110556fe01d1e…

MALICIOUS

PDF

92.7 KB Created: 2021-07-03 06:59:38 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-09-15
MD5: 40d0dd5cf5f272c52fdb6fe8559cc932 SHA-1: 0e9c30529c5e4cb0906e342ccf78d5039db586a4 SHA-256: 51f110556fe01d1e98d2677fab3119a671c6ddf8dc965569adc4482253e5a8f7
176 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous embedded URLs pointing to compromised WordPress sites, suggesting it's part of a link farm designed to redirect users to malicious content. The ML classifier and ClamAV detection strongly indicate malicious intent. While no scripts were explicitly extracted, the PDF structure and embedded links are indicative of a phishing or malware distribution lure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9786

Heuristics 7

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • Malformed active-content stream length medium PDF_MALFORMED_EXPLOIT_STREAM_LENGTH
    A PDF stream that carries active/exploit-looking content has a declared /Length that does not match the recovered stream body. Malformed stream boundaries and length mismatches are common parser-evasion/supporting evidence around Reader exploit streams.
  • 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 https://wurstfargo.com/wp-content/plugins/super-forms/uploads/php/files/79daaeac109ca8c00fe50cc94c7b532a/wuvok.pdf In PDF document text
    • https://braviengenharia.com.br/wp-content/plugins/super-forms/uploads/php/files/aj59scrs0cd5r6il4396n0v1jf/kiriwejuliwa.pdfIn PDF document text
    • https://arizonalightingsales.com/wp-content/plugins/super-forms/uploads/php/files/35b49220b197ef5e94a58ba05b274f4c/kerufumizugususoj.pdfIn PDF document text
    • https://lavaecucebrescia.it/file/wisim.pdfIn PDF document text
    • https://www.ciabrini-immobilier.com/wp-content/plugins/super-forms/uploads/php/files/itsoqnau10cg4sk294fggg71sh/31453196174.pdfIn PDF document text
    • http://metallpress.ru/files/volep.pdfIn PDF document text
    • http://www.iso-clean.fr/wp-content/plugins/formcraft/file-upload/server/content/files/16099166f1e032---47318679951.pdfIn PDF document text
    • https://ketgate.eu/wp-content/plugins/super-forms/uploads/php/files/87245bd20ef99189583ecccd78b88603/46701602247.pdfIn PDF document text
    • http://purifoy2020.com/clients/1/11/118d8b7ee1ea4bab8fb19da95c56260f/File/87249037735.pdfIn PDF document text
    • http://www.alquilerbares.com.ar/wp-content/plugins/formcraft/file-upload/server/content/files/160785bc08cb71---48463825635.pdfIn PDF document text
    • https://mkting.com.co/wp-content/plugins/super-forms/uploads/php/files/ea80e2d6cba171173f28e52dc77440c8/notoboronopixo.pdfIn PDF document text
    • http://xn--2vxr09c6mc.tw/CKEdit/upload/files/82214227572.pdfIn PDF document text
    • http://novussiteyonetimi.com/uploads/file/zaveporuvopozirorukev.pdfIn PDF document text
    • https://floridaholidayplanner.com/wp-content/plugins/super-forms/uploads/php/files/cab14938056cdbb476c34dbe385691da/gotujufisupuzaponese.pdfIn PDF document text
    • http://ideviceplus.nl/app/webroot/files/userfiles/files/nafawosifa.pdfIn PDF document text
    • https://www.c2commercial.com/wp-content/plugins/super-forms/uploads/php/files/087cc852eeaf76361ca18475c1276a97/43745493461.pdfIn PDF document text
    • https://ventana-sur.com/wp-content/plugins/formcraft/file-upload/server/content/files/160afc1a864eea.pdfIn PDF document text
    • http://www.rodnolespropertymanagement.com/siteuploads/editorimg/file/pipeku.pdfIn PDF document text
    • http://juniorsmagazine.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608843367cd8c---15539342702.pdfIn PDF document text
    • https://gift-edu.ru/wp-content/plugins/super-forms/uploads/php/files/c0bb04d75dad3c601fa7e23cc62f912d/65285381919.pdfIn PDF document text
    • https://www.arphplumbing.co.uk/wp-content/plugins/super-forms/uploads/php/files/2ap9a8t9v0v7m93u9om7gh26g3/fuzuvozikekogobegaru.pdfIn PDF document text
    • https://brahmagnanam.org/fck_uploads/file/gexiparepigezigutet.pdfIn PDF document text
    • https://3dreamstudios.com/wp-content/plugins/super-forms/uploads/php/files/32b2f1bd26448ff1c30b7998d62b06d5/34706972927.pdfIn PDF document text
    • http://inewbus.com/wp-content/plugins/super-forms/uploads/php/files/fdfic0ps16l3ibjh92rvek0hi5/741070867.pdfIn PDF document text
    • https://militarynetwork.ca/wp-content/plugins/formcraft/file-upload/server/content/files/160c63dd4cb89f---kowuna.pdfIn PDF document text
    • https://gresathouse.com/wp-content/plugins/super-forms/uploads/php/files/67b4c1631a11a9fbb02c2d1c3e37c425/67042977937.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/LPIa9PGmDLg/uplcv?utm_term=how+to+pronounce+the+word+pronouncePDF 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 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000f156.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF156 10320 bytes
SHA-256: 581ae2763923f5e6eb0268df6173c7574c0086e5ca149aa51ddf92788f9b0560
font_01_sfnt_off00010889.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10889 17532 bytes
SHA-256: 6a2df2ce63ad883f40f355256b46eb502e4a7da092944a1c6140bec0b5a87efb
font_02_sfnt_off00013599.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13599 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_03_sfnt_off00014daa.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x14DAA 16544 bytes
SHA-256: 66b7945b99a9c78025a9a0ace4161995b24b08b80ea391fd428eddc3553bac27