Malicious PDF — malware analysis report

Static analysis result for SHA-256 88be15d8f663d8dd…

MALICIOUS

PDF

75.3 KB Created: 2021-09-08 10:48:41 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: efe1d3341095570b25f1b97b9e84c1f2 SHA-1: 80cfae2fdc2aa8d9cc4f8a4a5de56cab4bc0b154 SHA-256: 88be15d8f663d8dd120aae4cbb5bf73ea76237a9ff6d66ea72e35f0897c02553
96 Risk Score

Malware Insights

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

The PDF document contains a large number of embedded URLs, many of which point to compromised CMS upload directories. The ML classifier strongly indicated maliciousness, and the link farm structure suggests an attempt to direct users to potentially harmful sites or manipulate search engine rankings. No scripts were extracted, limiting the analysis of direct execution vectors.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9973

Heuristics 5

  • 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://scro.ru/pic/file/75244953677.pdf In PDF document text
    • http://jiendurancecoaching.com/ckfinder/userfiles/files/pipenemexugajifutivabuve.pdfIn PDF document text
    • http://nek.ua/wp-content/plugins/formcraft/file-upload/server/content/files/160a7f2f2d53a4---54450255175.pdfIn PDF document text
    • http://www.maoles.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606f069454454---97614440253.pdfIn PDF document text
    • http://sobinco.cz/ckfinder/userfiles/files/921981746.pdfIn PDF document text
    • http://yuseigachi.nl/wp-content/plugins/formcraft/file-upload/server/content/files/16071df928b813---78205477884.pdfIn PDF document text
    • http://rymwid-training.com/userfiles/file/sokubibun.pdfIn PDF document text
    • http://businessnavigator.in/ckeditor/uploads/files/51658976531.pdfIn PDF document text
    • https://uaqbakery.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606cd22eeabcd---fofisawosagesevoranus.pdfIn PDF document text
    • http://goldstecq.com/userfiles/file/goxane.pdfIn PDF document text
    • http://kledingindex.nl/images/uploads/ketawarenumupepakako.pdfIn PDF document text
    • http://cn-junsheng.com/upload/file///202153012360644.pdfIn PDF document text
    • https://gyn-koe70.de/obrazky/file/12401076204.pdfIn PDF document text
    • https://yodishit.com/uploads/userfiles/file/wuwatotasabigegewovomu.pdfIn PDF document text
    • http://mobilesamara.com/img/files/file/6486177428.pdfIn PDF document text
    • https://www.costaverde.it/wp-content/plugins/formcraft/file-upload/server/content/files/160c2c654c6bc7---15498666513.pdfIn PDF document text
    • http://kwong-cheong.com/userfiles/4359242870.pdfIn PDF document text
    • http://turinhotelcompany.com/userfiles/files/roziwegupisebuwoloz.pdfIn PDF document text
    • https://prsnashville.com/wp-content/plugins/super-forms/uploads/php/files/4b43c0cbef5a9cfce52421a1512e62a8/16684740773.pdfIn PDF document text
    • http://studioingegneramato.com/userfiles/files/boxuxaw.pdfIn PDF document text
    • http://travelport.pl/userfiles//file/91586990709.pdfIn PDF document text
    • https://www.etbsupplies.com/wp-content/plugins/formcraft/file-upload/server/content/files/16095e1090ea9a---tumugewanex.pdfIn PDF document text
    • http://zoncmswebsitebeheer.nl/files/editor/file/91674883469.pdfIn PDF document text
    • http://gyndoktors.de/ckfinder/userfiles/files/febojez.pdfIn PDF document text
    • http://www.altrus.pl/wp-content/plugins/formcraft/file-upload/server/content/files/160771c69ace25---47548229862.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/BvfzZFkJO3s/uplcv?utm_term=career+research+worksheet+for+high+school+studentsPDF 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_off0000c386.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC386 16428 bytes
SHA-256: fbd56229906db00a7b2c12a640b9829f2fdfadcb358ae59c5c61de326f391718
font_01_sfnt_off0000ed38.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xED38 11064 bytes
SHA-256: adb5569cff7be60b0b3caef12aa76e0189d6ce5037d6d2ca6d0d2f52f3146931
font_02_sfnt_off000106db.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x106DB 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1