Malicious PDF — malware analysis report

Static analysis result for SHA-256 a737b754835e99d5…

MALICIOUS

PDF

87.7 KB Created: 2021-06-26 09:00:38 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-09-13
MD5: e9fd7addae57c2f9146589749ca0390c SHA-1: 296151d15f79d5aab1d61025341a21326b42c102 SHA-256: a737b754835e99d53c798ec49ace7d258c1562d3754c42be5973709c2fc0ad14
156 Risk Score

Malware Insights

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

The sample is identified as a malicious PDF by multiple heuristics and a machine learning classifier. It contains numerous links pointing to compromised WordPress upload storage and other domains, suggesting it's part of a link farm designed to redirect users. The ClamAV detection as 'Pdf.Phishing.Trojan' further supports its malicious nature. The primary attack pattern involves luring users to potentially malicious external sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9992

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 https://firsatpin.com/calisma2/files/uploads/80938953190.pdf In PDF document text
    • https://tailormade-sales-marketing.com/userfiles/file/subofel.pdfIn PDF document text
    • https://rubenoferro.com/userfiles/file/99386728183.pdfIn PDF document text
    • http://dedanskecasinoer.dk/userfiles/file/70046230272.pdfIn PDF document text
    • https://noukos.gr/wp-content/plugins/formcraft/file-upload/server/content/files/160989172c6d32---31416112788.pdfIn PDF document text
    • https://psychotherapie-dr-albrecht.de/wp-content/plugins/formcraft/file-upload/server/content/files/160c4fb61e6ae6---31233864239.pdfIn PDF document text
    • https://suhrsmad.dk/wp-content/plugins/formcraft/file-upload/server/content/files/160d671bd87eeb---rurubasedumasu.pdfIn PDF document text
    • https://www.mysmilestudios.com/wp-content/plugins/super-forms/uploads/php/files/46eab23def6461b4d41e01f634b513d3/45003146387.pdfIn PDF document text
    • http://jestbogiem.pl/app/webroot/uploads/file/99609246472.pdfIn PDF document text
    • https://www.unicodesystems.com/wp-content/plugins/super-forms/uploads/php/files/7de76jdbkqj0hoeoi7a12dpcs5/97214120030.pdfIn PDF document text
    • https://qnzar.com/files/rebuvoxovuxopugupimomiv.pdfIn PDF document text
    • http://churchliferesources.org/wp-content/plugins/formcraft/file-upload/server/content/files/16099b821df876---43423396335.pdfIn PDF document text
    • https://naucharts.com/ckfinder/userfiles/files/60674419953.pdfIn PDF document text
    • http://sushikyototogo.com/uploads/files/43673057248.pdfIn PDF document text
    • https://qualitycountscleaning.com/wp-content/plugins/super-forms/uploads/php/files/3507148a2aadb3c03fb9f252097f6f8b/31244364858.pdfIn PDF document text
    • http://kaowei.tw/image/files/20210527_174345.pdfIn PDF document text
    • http://www.linkkorea.co.kr/wp-content/plugins/formcraft/file-upload/server/content/files/160b1ea4ca38dd---libefilujidi.pdfIn PDF document text
    • http://creative-format.com/upload/editor/files/50417699879.pdfIn PDF document text
    • http://dlikefulproductions.com/clients/875850/File/83631384807.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/zMnd8XtcwSM/uplcv?utm_term=wow+classic+mage+aoePDF 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_off0000f6d3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF6D3 16780 bytes
SHA-256: 5978a35cc4e956a8f7df860eb2fcb1b4672c1d06e67efa4faa9f732ce88acdc3
font_01_sfnt_off00012278.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12278 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00013a8f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13A8F 10348 bytes
SHA-256: b3b114b689b0546548d5c70c673c1d27f28765b478b765775e73156703c9075b