Malicious PDF — malware analysis report

Static analysis result for SHA-256 91df35457dc5e588…

MALICIOUS

PDF

71.7 KB Created: 2021-09-16 19:14:47 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 91830b9bf2ebd56ec3568d048326fe21 SHA-1: 041afcf27b529ce99f7dfa9304d8d7cc6577f1a0 SHA-256: 91df35457dc5e588f6e7c651df702859e43788d45d9626b195261c7ab9016364
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file is identified as malicious by ML classifiers and ClamAV, with heuristics indicating it functions as a link farm pointing to numerous disposable hosting sites. The presence of external URIs and a link farm structure suggests the primary goal is to redirect users to potentially malicious content, likely for phishing or malware delivery. No scripts were extracted, but the PDF structure itself facilitates the attack.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9956

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://coretry.ru/uplcv?utm_term=gba+pro+emulator PDF link annotation
    • http://madmojo.com/fckupload/file/wimumotivavigip.pdfIn PDF document text
    • http://sinojjacob.com/userfiles/file/niluzodoxa.pdfIn PDF document text
    • https://anmimar.com/royal/userfiles/file/pivisobotejujufuputos.pdfIn PDF document text
    • http://medica-brno.com/files/93020287326.pdfIn PDF document text
    • http://www.pzkexie.com/up_files/file/xovekiketowobazibufixo.pdfIn PDF document text
    • https://pnp-studio.com/fckeditorfiles/file/tefufapu.pdfIn PDF document text
    • http://leeclinic.kr/userData/board/file/34706555942.pdfIn PDF document text
    • http://vladjurnalist.ru/archive/file/54042238141.pdfIn PDF document text
    • http://talani.nl/userfiles/image/file/salogali.pdfIn PDF document text
    • http://www.insurancedirectcanada.ca/wp-content/plugins/formcraft/file-upload/server/content/files/1614155cfe4ffe---miwobigoxo.pdfIn PDF document text
    • https://completecollegestrategies.com/wp-content/plugins/super-forms/uploads/php/files/ec6185a8ce0119732b0aba6590dffbbe/88868061126.pdfIn PDF document text
    • http://angelofthewinds.org/ckfinder/userfiles/files/14710982226.pdfIn PDF document text
    • http://kkc1.org/htdocs/cljr/data/files/57601505804.pdfIn PDF document text
    • http://www.naraihillgolf.com/admin/userfiles/file/vozolepiwidatiridaditono.pdfIn PDF document text
    • http://escolacaritas.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613df65b959e1---pefujirowo.pdfIn PDF document text
    • http://kantipursecurity.com/userfiles/file/55805019131.pdfIn PDF document text
    • https://www.thecandystoresudbury.com/wp-content/plugins/super-forms/uploads/php/files/252n7fb6khe00moj715kldpn3b/65657983238.pdfIn PDF document text
    • http://2m-m.eu/userfiles/files/30196948764.pdfIn PDF document text
    • http://ahknchem.com/upload/files/69937487486.pdfIn PDF document text
    • https://assurancemauricie.com/wp-content/plugins/formcraft/file-upload/server/content/files/16138e2fccd85e---zoxenobudofexejevora.pdfIn PDF document text
    • http://aeskulap24h.de/wp-content/plugins/formcraft/file-upload/server/content/files/1613e6fb4d512b---76750885908.pdfIn PDF document text
    • http://serendipityorlando.com/wp-content/plugins/formcraft/file-upload/server/content/files/16141c809cc859---wujojezazafekeximomi.pdfIn PDF document text
    • https://amesmedicalservices.com/wp-content/plugins/formcraft/file-upload/server/content/files/16142d9eaccac5---wozofefezogobefagam.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_off0000b538.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB538 10328 bytes
SHA-256: 0029d423280770c03262940d2777596957407e5111924422fd96ec88aef68d6a
font_01_sfnt_off0000cc5b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCC5B 17364 bytes
SHA-256: d84465f19de5d5d6a13caae208e998c45bae1bdfe33a604f295a4d9a0f018280
font_02_sfnt_off0000f993.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF993 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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