Malicious PDF — malware analysis report

Static analysis result for SHA-256 53e0598ea1f0a0e5…

MALICIOUS

PDF

91.3 KB Created: 2021-09-18 16:04:13 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: 3c77c756c73d339c1295154ce6704eea SHA-1: 68f0c354a44ef8406d0dbdd1a257009b9b80f808 SHA-256: 53e0598ea1f0a0e52b19863ef2c3c2ebe115ca2b14a6dcee07967b75d49a6490
96 Risk Score

Malware Insights

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

The PDF file contains a link farm pointing to numerous other PDF files, many hosted on compromised WordPress sites or disposable domains. The ML classifier strongly indicates maliciousness, and the structure suggests an attempt to manipulate search engine results or distribute further malicious content. No scripts were extracted, but the overall pattern is indicative of a malicious document distribution or SEO poisoning campaign.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9982

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://dayou.tw/uploadpic/files/202109050442575718.pdf In PDF document text
    • http://lncxjzxxw.com/upload_fck/file/2021-9-17/20210917115617377720.pdfIn PDF document text
    • http://nbnjl.com/userfiles/files/wamufidijowatapinabagomiz.pdfIn PDF document text
    • http://beckydavidsonhomes.com/wp-content/plugins/formcraft/file-upload/server/content/files/16138a83a08a29---66470438296.pdfIn PDF document text
    • http://khocabien.com/uploads/files/dedilisitosu.pdfIn PDF document text
    • http://saltokisport.com/uploads/files/dupalowetuwewuvimisas.pdfIn PDF document text
    • http://griesvoegwerken.nl/UserFiles/file/95700548894.pdfIn PDF document text
    • http://supragyn.cz/userfiles/file/nudopipuzabexalav.pdfIn PDF document text
    • http://www.leesii.com/wp-content/plugins/formcraft/file-upload/server/content/files/1612fcf22ee98d---buforobenetax.pdfIn PDF document text
    • http://guss-ex.de/uploads/fck/file/tetofiz.pdfIn PDF document text
    • http://chono.mn/uploads/userfiles/files/45855083761.pdfIn PDF document text
    • http://infinity-c-t.com/userfiles/file/16423916006.pdfIn PDF document text
    • http://at2apigroup3.com/contents/files/wexuli.pdfIn PDF document text
    • http://headlinesdinerla.com/uploads/files/1921837015.pdfIn PDF document text
    • https://lordoptika.hu/files/files/momifalegepozejule.pdfIn PDF document text
    • http://ck-kutnahora.cz/gais/image/file/63263727008.pdfIn PDF document text
    • https://eagle-aviation.com/userfiles/files/jagezadawonavu.pdfIn PDF document text
    • http://eot.mn/uploads/userfiles/files/tidebos.pdfIn PDF document text
    • http://www.airportlimofortlauderdale.net/wp-content/plugins/formcraft/file-upload/server/content/files/1612fd9e193417---91440279079.pdfIn PDF document text
    • https://partroyfuneralhome.com/partroy/assets/file/xukesesudotib.pdfIn PDF document text
    • https://decisionstogo.com/fck_image/file/bemadufopezudem.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/LPIa9PGmDLg/uplcv?utm_term=excel+macro+to+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_off0000fd97.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFD97 19072 bytes
SHA-256: 19c19a74d29430dc8f7d8c2fe84c070e0773789e7327d9949bd773e0619bc4b5
font_01_sfnt_off00012fda.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12FDA 10500 bytes
SHA-256: 8e5844538a5e07c76811bf47a29a778ab7a9ce4d83f16ee9e5647f1766d3acac
font_02_sfnt_off000147c4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x147C4 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1