Malicious PDF — malware analysis report

Static analysis result for SHA-256 883a236cff1ba6da…

MALICIOUS

PDF

77.2 KB Created: 2021-09-21 18:16:52 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: 4969f34df39b2def1015558f9e8a46d4 SHA-1: a77605e6ab1b0859d331e8049ed46d1f81b53b7b SHA-256: 883a236cff1ba6dadba2289674e62f16a4a90bac3d5b27b1e3b4d8a44afb0b35
156 Risk Score

Malware Insights

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

The PDF file was flagged by ML classifiers and ClamAV as malicious, indicating a high likelihood of malicious intent. It contains numerous external links, many pointing to compromised CMS upload directories or disposable hosting, suggesting a link farm designed to redirect users to malicious sites. The document body is heavily obfuscated and unreadable, but the presence of external URIs and the PDF_SEO_DISPOSABLE_LINK_FARM heuristic strongly suggest a phishing or malware distribution campaign.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9973

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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 https://synerhu.ru/uplcv?utm_term=android+xml+layout+templates+free PDF link annotation
    • http://lagrupacio.cat/file/35684575996.pdfIn PDF document text
    • http://njbeihang.com/uploadfile/file///2021090503194423.pdfIn PDF document text
    • https://xcheck.vn/uploads/userfiles/file/dujoralipudabujuni.pdfIn PDF document text
    • http://skuplaptop.pl/wp-content/plugins/formcraft/file-upload/server/content/files/161406ffeacc7b---wexamosup.pdfIn PDF document text
    • http://lmalaw.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/54459303006.pdfIn PDF document text
    • https://thokhoavietnam.com/upload/files/20073642529.pdfIn PDF document text
    • http://reiki-roots.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/161491390ad075---bivilorowixituzudadaburin.pdfIn PDF document text
    • http://www.telsercom.com/wp-content/plugins/formcraft/file-upload/server/content/files/161327c05bd981---29421666309.pdfIn PDF document text
    • http://www.thelawchamber.com/wp-content/plugins/formcraft/file-upload/server/content/files/16135fffa196ce---wapinokipuv.pdfIn PDF document text
    • http://husplaza.hu/editor_up/fofovavatudope.pdfIn PDF document text
    • http://niestachow.pl/data/aktualnosci_imgs/file/30773665868.pdfIn PDF document text
    • http://shijijiaming.cn/filespath/files/20210907130007.pdfIn PDF document text
    • http://office-agglo-larochelle.fr/userfiles/file/fofigogobiwuzakotubafi.pdfIn PDF document text
    • http://thangmayedex.com/webroot/img/files/vujesiramuxekanuwemexuj.pdfIn PDF document text
    • http://otestmanager.org/club/data/userfiles/file/20210912221825.pdfIn PDF document text
    • http://altera.ukrstroyka.com/content/xuploadimages/file/84479936361.pdfIn PDF document text
    • http://gutachterbewertung.de/userfiles/file/wofamawexamapatafuxuwos.pdfIn PDF document text
    • http://livilgirls.com/files/rotanatukokaboturixer.pdfIn PDF document text
    • http://thaicockstar.com/ckfinder/userfiles/files/tunusofutexunowekivopid.pdfIn PDF document text
    • https://www.tocbirsen.org.tr/ckfinder/userfiles/files/30299597767.pdfIn PDF document text
    • https://ceccardolj.ro/userfiles/file/bijilazesininugu.pdfIn PDF document text
    • https://tw-itemaos.com/ckfinder/userfiles/files/65497481423.pdfIn PDF document text
    • http://reiki-roots.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/1613efef26ef4e---xisosujogetajupazonan.pdfIn PDF document text
    • http://www.peplex.it/wp-content/plugins/formcraft/file-upload/server/content/files/16140494fc9310---7553942743.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_off0000cb6d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCB6D 10956 bytes
SHA-256: 135a72708ff924ec20937b7f6e519523612d7df27b6a2d0b7f08626e7f28809d
font_01_sfnt_off0000e4dd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE4DD 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000fcef.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFCEF 16268 bytes
SHA-256: 9915f3c66cec07e9d79552c1e21013deac2aa3662c1a52e58e4852ca7f0ba66a

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