Malicious PDF — malware analysis report

Static analysis result for SHA-256 b146a5b1db19bd90…

MALICIOUS

PDF

84.9 KB Created: 2021-09-01 23:11:52 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-05
MD5: 8623c091e7334aa04dee081fe2677fe5 SHA-1: c5a7deb837c6c99fcbce63757f09de9e51ebe21a SHA-256: b146a5b1db19bd9086ea740432b094e93894d7f1800f882824921ba8ca4fbdfe
156 Risk Score

Malware Insights

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

The PDF was flagged by ClamAV as Pdf.Phishing.Trojan and an ML classifier indicated a high probability of maliciousness. It contains numerous external URIs and link farm heuristics, suggesting it is designed to redirect users to potentially malicious websites. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, further indicating a non-standard document structure likely used for malicious purposes.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9978

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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 https://chcial.ru/uplcv?utm_term=beauty+is+in+the+eye+of+the+beholder+quote PDF link annotation
    • https://vinniescustoms.com/userfiles/files/gegetajufemozawetugefepa.pdfIn PDF document text
    • https://digireg.nu/upload/24405891131.pdfIn PDF document text
    • https://doellefjelde-mussemarked.dk/images/newsmail/file/4026695124.pdfIn PDF document text
    • https://xn----9sbccjdbca7cyaieg1a3j.xn--p1ai/wp-content/plugins/super-forms/uploads/php/files/1928540f98e59754b884740e6514fb8c/88283588042.pdfIn PDF document text
    • http://freemansphotography.com/wp-content/plugins/formcraft/file-upload/server/content/files/16077d38caa0f9---54903922153.pdfIn PDF document text
    • http://elitvorota.ru/f/file/53016862599.pdfIn PDF document text
    • http://alpha-th.com/userfiles/file/dirajarejebeza.pdfIn PDF document text
    • http://korean-school.hu/hangul/userfiles/file/numiwerokulutafixanixov.pdfIn PDF document text
    • https://wlao.on.ca/wp-content/plugins/super-forms/uploads/php/files/0f848d23f675acf668e1bbf821f224e1/xafejafifufu.pdfIn PDF document text
    • https://interativacorretora.com/fotosempresa/files/toxarakixu.pdfIn PDF document text
    • http://hrzservices.com/uploadfiles/file/vijokelan.pdfIn PDF document text
    • http://kaufdeinauto.de/wp-content/plugins/formcraft/file-upload/server/content/files/1609d1acd4b84d---foroselidilulogapa.pdfIn PDF document text
    • http://www.trisad.kz/ckfinder/userfiles/files/80038612262.pdfIn PDF document text
    • https://beribuket.ru/wp-content/plugins/super-forms/uploads/php/files/499db82620c2f162bae3a28fd885dac9/zaxulilinam.pdfIn PDF document text
    • http://www.goldenlantern.co.za/wp-content/plugins/formcraft/file-upload/server/content/files/160774fa04a70e---44700931684.pdfIn PDF document text
    • http://xn--eyt274i.com/upload/files/jotizivelevuzewigun.pdfIn PDF document text
    • http://jsushibrea.com/uploads/files/778421188.pdfIn PDF document text
    • http://hoanggiaphatstone.com/upload/files/mafigeziwat.pdfIn PDF document text
    • https://fieldofgreen.com/wp-content/plugins/super-forms/uploads/php/files/ac8083ad4c7061b8a14488a1fce63757/kuposelamijetudimub.pdfIn PDF document text
    • https://citytrafik.nu/images/file/56519391743.pdfIn PDF document text
    • http://nissanotogovap.net/uploads/images/files/budos.pdfIn PDF document text
    • http://flatadministration.com/uploades/fckeditorfile/30461617537.pdfIn PDF document text
    • http://timatey.kz/wp-content/plugins/super-forms/uploads/php/files/5dirra51k8k9qesj4egjftptm1/fibagosuwelenojaxisuzo.pdfIn PDF document text
    • https://mission4recruitment.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606f1ae3094b6---wimobemilavajifowigali.pdfIn PDF document text
    • 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_off0000e3da.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE3DA 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000fbf1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFBF1 11004 bytes
SHA-256: 636ff1bd087d59fca14be39c10b3831d235d1266b1b4bd69edc98c2c4e50ce72
font_02_sfnt_off00011540.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11540 17948 bytes
SHA-256: 885cb5ff5cb738a617a7e2a8918b7332fbc4fcb67cae707042c0ac27e4f8286f