Malicious PDF — malware analysis report

Static analysis result for SHA-256 5b824d9158fe97f1…

MALICIOUS

PDF

77.7 KB Created: 2021-09-16 11:25:02 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: 7a682f616c76ae38993990e847cab61f SHA-1: 431f6440f34f9732215ac5416d6dc9cf78505e37 SHA-256: 5b824d9158fe97f1d7103543da2a19d44cbb8423117a762da909b1ca2eb12d73
96 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF contains numerous embedded URLs, many pointing to compromised websites or disposable hosting, indicating a link farm designed to redirect users. The ML classifier strongly flagged this PDF as malicious, and the presence of compromised CMS upload links further supports a malicious intent, likely for phishing or malware distribution.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9948

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 https://krisoc.ru/uplcv?utm_term=whatsapp+status+saver+apk+download PDF link annotation
    • http://thuephotocopytaihanoi.com/upload/files/66928489235.pdfIn PDF document text
    • https://wickedcheesy.com/images/file/57811100490.pdfIn PDF document text
    • http://studiopassarotti.it/userfiles/files/15814069303.pdfIn PDF document text
    • http://maekalocal.com/Maeka/UserFiles/File/49155675610.pdfIn PDF document text
    • https://sgotomotiv.org/upload/files/51792309437.pdfIn PDF document text
    • http://filippodelvita.com/demo/userfiles/file/dezipiwosujoremukurato.pdfIn PDF document text
    • https://adiwirawanbali.com/wp-content/plugins/super-forms/uploads/php/files/95a1188b28c89231a54ae48d820250b3/3648051280.pdfIn PDF document text
    • http://fotosvatba.net/userfiles/file/xujan.pdfIn PDF document text
    • https://kindliving.org/wp-content/plugins/super-forms/uploads/php/files/tmp/xijapel.pdfIn PDF document text
    • http://ophirtonhotel.co.za/wp-content/plugins/formcraft/file-upload/server/content/files/1612eaf5fecec7---jeloguredututunoke.pdfIn PDF document text
    • http://duocthientam.com/uploads/ckfinder/files/82677143670.pdfIn PDF document text
    • http://bbfederico2.net/userfiles/file/88861455621.pdfIn PDF document text
    • https://8cj2aja7-8mxb.com/contents/files/larituguz.pdfIn PDF document text
    • http://gyarmatilovastorna.hu/userfiles/file/daraxutikavo.pdfIn PDF document text
    • http://francescasciortino.it/userfiles/files/85312211857.pdfIn PDF document text
    • https://valenciamaids.com/userfiles/files/gefaworoboraxowobekufaje.pdfIn PDF document text
    • https://rlmahtani.com/userfiles/files/moduzelanapinuveji.pdfIn PDF document text
    • https://estidevelopers.com/wp-content/plugins/super-forms/uploads/php/files/5b59091ba997fe37980e76e0ced5d0e2/74047299192.pdfIn PDF document text
    • https://www.carlosfunes.es/wp-content/plugins/formcraft/file-upload/server/content/files/16141f1a3cfff5---49404245793.pdfIn PDF document text
    • http://runbo.net/upfiles/files/16310531696101.pdfIn PDF document text
    • https://doublehaircenter.com/upload/ckfinder/files/50809873784.pdfIn PDF document text
    • http://dienlanhtruongson.com/upload/files/86674753571.pdfIn PDF document text
    • https://e-fasteners.eu/media/file/beguxupetazupotaruve.pdfIn PDF document text
    • http://fra2ange.it/userfiles/files/82319659391.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_off0000cbc2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCBC2 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000e3d4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE3D4 17176 bytes
SHA-256: c1d28c02c4cc3ba22fc17eedff37f8af19257f215a02f21a286dc9333e2244c4
font_02_sfnt_off00011068.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11068 10736 bytes
SHA-256: d9d5f1ffe4caf50c5ea653efca6bff48adb62f77b03e4b8503d9c619f0d98957