Malicious PDF — malware analysis report

Static analysis result for SHA-256 f3fb481de155cb1b…

MALICIOUS

PDF

80.6 KB Created: 2021-08-24 23:41:32 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: de82b567c276c960c27af31830469289 SHA-1: 6e3c0cd7b2a379589b82598cd74333ff10fc4e54 SHA-256: f3fb481de155cb1b944e2e8bd1c9261d4ac7f13025d261091b187f53326c1038
156 Risk Score

Malware Insights

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

The PDF contains numerous links, many pointing to compromised WordPress upload directories or disposable hosting, suggesting a link farm or SEO spamming operation. The ML classifier and ClamAV detection strongly indicate malicious intent, likely phishing or malware distribution. The document body is heavily obfuscated and unreadable, providing no direct clues to its purpose beyond the embedded links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

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 http://majorpropertygroup.com/userfiles/files/lowilupinu.pdf In PDF document text
    • http://gayaarchi.com/userfiles/file/20210517181405.pdfIn PDF document text
    • https://istanbulbalbir.com/upload/ckfinder/files/34158313459.pdfIn PDF document text
    • http://friulanapanini.com/images/file/tajim.pdfIn PDF document text
    • http://tokstar.com/_UploadFile/Images/file/25386332114.pdfIn PDF document text
    • http://tai-yang.tw/taiyang/upload/file/gukurageniresunepene.pdfIn PDF document text
    • http://szyldkj.com/luodan/images/userfiles/file/tinegerozubewid.pdfIn PDF document text
    • http://thepdaitruongphat.com/upload/ck/files/penuraxeloxatagex.pdfIn PDF document text
    • http://southport1969.com/clients/861680/File/virep.pdfIn PDF document text
    • https://nonbodepsg.com/uploads/files/46650906937.pdfIn PDF document text
    • https://koltoztetes-szallitas-lomtalanitas.com/ckfinder/userfiles/files/xolorinanebikup.pdfIn PDF document text
    • http://plenaadoracao.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160c40f4a2101b---fowutabilif.pdfIn PDF document text
    • http://starlightcelebrates.ca/clients/4/43/43e9139217482d7666ce300faf566241/File/pumobekuxidenena.pdfIn PDF document text
    • https://dom4m.de/userfiles/files/4521689774.pdfIn PDF document text
    • https://nationalcardsolutions.com/wp-content/plugins/formcraft/file-upload/server/content/files/16071f7da927c0---bawasagisuvotosokarixe.pdfIn PDF document text
    • https://centrumschoolka.pl/photos/file/43361789373.pdfIn PDF document text
    • https://criteriacambio.com.br/wp-content/plugins/super-forms/uploads/php/files/b27tso6eh7183b7us8pr7tuet0/tuwuko.pdfIn PDF document text
    • http://jiangsutravel.kr/userfiles/files/20210607_015545.pdfIn PDF document text
    • http://ronniejoymemorialfund.com/clients/1/1a/1a75100f29d804137a154ca93ef51a80/File/lakus.pdfIn PDF document text
    • https://hydratrend.com/application/third_party/ckfinder/userfiles/files/75966542137.pdfIn PDF document text
    • https://hyundainhapkhau.vn/upload/files/66078148098.pdfIn PDF document text
    • https://www.dazzlingdecor.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/16074a5bfbebe4---16249072978.pdfIn PDF document text
    • http://www.ncstarim.com.tr/wp-content/plugins/super-forms/uploads/php/files/907lh7vfs7afgvbnivt41etrc0/27155109561.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/BkSY9tpko7c/uplcv?utm_term=squishing+up+a+baby+bumblebeePDF 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_off0000d924.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD924 10956 bytes
SHA-256: 6e75668c3438a903b61092e685149a46ebe466d07f85a86f9e83a8bd80ac9102
font_01_sfnt_off0000f1c8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF1C8 16856 bytes
SHA-256: 01a109ed42f9f49dfb0a0a6a2965435d10990c5d72bf1a1c7550df55afb1d83a
font_02_sfnt_off00011d9a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11D9A 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1