Malicious PDF — malware analysis report

Static analysis result for SHA-256 b5c91799303fd817…

MALICIOUS

PDF

78.7 KB Created: 2021-06-10 19:57:22 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-16
MD5: 08560dc748b61f5dd841efb74d84ba23 SHA-1: a029f82922cf67256e8dfc780e96ae3712793cf2 SHA-256: b5c91799303fd8174871d4118cde88f8d51c9bc898870bf3f5bc4e87da5c9cfc
156 Risk Score

Malware Insights

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

This PDF file was flagged by a machine learning classifier and ClamAV as malicious, specifically as a phishing trojan. It contains numerous external URLs, many of which point to compromised WordPress sites acting as link farms. The document body is heavily obfuscated and appears to be a lure, likely intended to redirect users to malicious sites for further exploitation or credential harvesting.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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://crysiq.ru/uplcv?utm_term=the+english+alphabet+pdf PDF link annotation
    • https://salubrismd.com/wp-content/plugins/super-forms/uploads/php/files/67787ae0082c07e73d7955501d51d916/10954462789.pdfIn PDF document text
    • https://emergent-partners.com/wp-content/plugins/formcraft/file-upload/server/content/files/160736f6e5478a---fatimawezo.pdfIn PDF document text
    • http://chicagohalo.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609ceb340384c---muguripokinojorinaxifilo.pdfIn PDF document text
    • https://amezdigital.com/wp-content/plugins/super-forms/uploads/php/files/90826a9867c138e02cf34b6fdf048c62/sogofopotofix.pdfIn PDF document text
    • https://humble-brag.com/wp-content/plugins/super-forms/uploads/php/files/mrvs8djamc7dbajk4gco7h1hv7/lujuwigi.pdfIn PDF document text
    • https://www.gsccn.it/wp-content/plugins/formcraft/file-upload/server/content/files/1608d78b57019c---49964689687.pdfIn PDF document text
    • http://thehawthornnyc.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608203253f92b---84185993714.pdfIn PDF document text
    • https://www.infratechgroep.nl/wp-content/plugins/super-forms/uploads/php/files/cbd3186eeecc85ca7c2630e22add05aa/88651116248.pdfIn PDF document text
    • http://atthaya.com/file_media/file_image/file/nifunilusekom.pdfIn PDF document text
    • http://hillsdale66ersreunion.com/clients/c/c6/c679c52642bc64dd8629b98fb95ccc77/File/notimigikuxosida.pdfIn PDF document text
    • https://theemperorsoldclothes.co.uk/wp-content/plugins/super-forms/uploads/php/files/iqe6l2aqm11krb9bgusg2kt4sv/kogalisom.pdfIn PDF document text
    • https://www.lipfish.no/wp-content/plugins/formcraft/file-upload/server/content/files/1607c644eac485---vemun.pdfIn PDF document text
    • https://www.verpoort-bouw.be/wp-content/plugins/formcraft/file-upload/server/content/files/1607e8855e35fd---58534451693.pdfIn PDF document text
    • http://flatadministration.com/uploades/fckeditorfile/berewomowapelexes.pdfIn PDF document text
    • https://belgradenightlife.info/wp-content/plugins/super-forms/uploads/php/files/cd4l61m5bghks8lksi31kfha5l/95370189875.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn 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://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000f5a9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF5A9 5296 bytes
SHA-256: 29e8ac7e02d2ea06e13da740f63170a773d2f6a9f08ac5f11b0e76d8d9190f8d
font_01_sfnt_off000107aa.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x107AA 11316 bytes
SHA-256: 15ee675a5c9a12b40a7fe204fa7bf43c0a058f80aa59584bdf55f6253332eedd