Malicious PDF — malware analysis report

Static analysis result for SHA-256 739c43365c472dba…

MALICIOUS

PDF

77.6 KB Created: 2021-09-08 08:46:12 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: 897a085c8c70b6e075b88d54f707c87a SHA-1: 7dc4e9f0230e03123945642cdf68097f34cedaad SHA-256: 739c43365c472dbafdeb7a30dbe9fdbf065ae459ec0977ceadc51753ef48b1f9
96 Risk Score

Malware Insights

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

The PDF contains a link farm pointing to multiple compromised WordPress sites, which in turn host other PDF files. This suggests a multi-stage attack where the initial PDF serves as a lure to download further malicious content. The ML classifier strongly indicated maliciousness, and the structure of the links points towards an attempt to distribute malicious documents.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9953

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://earthideasawnings.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a64e5006945---79383658202.pdf In PDF document text
    • http://www.musicmaestrodiscos.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/1607f27f043451---40907068992.pdfIn PDF document text
    • http://ontheedgeofnow.com/wp-content/plugins/formcraft/file-upload/server/content/files/16083f66c742bc---jumobogokirutoloju.pdfIn PDF document text
    • http://donaldnathanlaw.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/55084878149.pdfIn PDF document text
    • https://bitree.ru/ckfinder/userfiles/files/1173976171.pdfIn PDF document text
    • http://dasbluemchen.com/ziwidimebujigubokedo.pdfIn PDF document text
    • https://idfusionllc.com/wp-content/plugins/super-forms/uploads/php/files/87aa635c74a2d827df3ca17c075d1440/38464289455.pdfIn PDF document text
    • https://agrotehholding.ru/wp-content/plugins/super-forms/uploads/php/files/ecffdd3d16341cace9e187aba21d74e5/wemug.pdfIn PDF document text
    • https://pointswestliving.com/ckfinder/userfiles/files/xuvutijijetote.pdfIn PDF document text
    • http://www.kissdocs.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/16095bc2744480---lozirulujutadimefodeno.pdfIn PDF document text
    • https://literie-depot.fr/UserFiles/file/98368048151.pdfIn PDF document text
    • https://tasteadmin.com/ckfinder/core/connector/php/custom/wysi_uploads/files/72163597338.pdfIn PDF document text
    • http://www.auditsi.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c0556485d02---60670491478.pdfIn PDF document text
    • https://meesens.be/KrMee/Tekstverwerker/51328724318.pdfIn PDF document text
    • https://sellos-mecanicos.com/wp-content/plugins/super-forms/uploads/php/files/b1991fd57182360f645d119b20b1d2e5/xonilo.pdfIn PDF document text
    • https://www.synergyheart2heart.team/wp-content/plugins/super-forms/uploads/php/files/mik8k0i34ute9gr060n62p079i/bopabu.pdfIn PDF document text
    • http://affordableadobe.com/ckfinder/userfiles/files/71478589118.pdfIn PDF document text
    • https://777mto.org/contents//files/febafivajo.pdfIn PDF document text
    • https://www.gml.de/wp-content/plugins/formcraft/file-upload/server/content/files/160b436c14f549---46332332810.pdfIn PDF document text
    • http://tramtronbetong.com/uploads/userfiles/file/19371839309.pdfIn PDF document text
    • http://alltechsro.cz/files/88249074816.pdfIn PDF document text
    • http://terezmisszio.eu/files/file/fimelujuparowinifufel.pdfIn PDF document text
    • http://xn--m1age8bh.xn--p1ai/files/file/fogawasevakorotup.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/6naE_Nh8_CY/uplcv?utm_term=word+sorts+for+within+word+pattern+spellers+pdfPDF 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_off0000c9c4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC9C4 10672 bytes
SHA-256: 802962f669db0a7f2f68ded855a4bad1ce804e23069dc4ad5d58a411044dff47
font_01_sfnt_off0000e231.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE231 17888 bytes
SHA-256: af8f4b75708c0b61de35e3344f4e23a9645db8798dec61c0c0329b47c15f469e
font_02_sfnt_off000110df.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x110DF 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1