Malicious PDF — malware analysis report

Static analysis result for SHA-256 88099e413d7f16f8…

MALICIOUS

PDF

71.1 KB Created: 2021-09-29 12:00:58 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 713b4aa73f1be6fd473fc1cb8668ca9d SHA-1: 64b21429ff8deb1fb8f18e99d0c54e5aac2cb404 SHA-256: 88099e413d7f16f89a3777c464f190c7f374dad28cee56d69151443333c61a4c
156 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs, many of which point to compromised CMS upload storage or disposable hosting, indicating a link farm designed to redirect users. The ML classifier and ClamAV detection strongly suggest malicious intent, likely for phishing or malware distribution. No scripts were extracted, and the document body was unreadable, but the heuristic firings and URL analysis are sufficient to determine the attack pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

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 http://sakra.sk/storage/file/68567430137.pdf In PDF document text
    • https://baust.edu.bd/app/webroot/ckfinder/userfiles/files/vitumuxugi.pdfIn PDF document text
    • http://www.1000ena.com/wp-content/plugins/formcraft/file-upload/server/content/files/1614e04222b4de---11305782344.pdfIn PDF document text
    • https://angelsolutions.ro/ckeditor/ckfinder/userfiles/files/kirinuxovirevu.pdfIn PDF document text
    • https://a-pointpro.com/cms/ckfinder/userfiles/files/toxenedavixowuker.pdfIn PDF document text
    • https://cfacgroup.com/uploads/FCK_files/file/pegaxuvasodole.pdfIn PDF document text
    • http://hansungidschool.com/userfiles/file/98445130126.pdfIn PDF document text
    • https://majubesar.info/contents/files/fuvasefogoxowunisoxufin.pdfIn PDF document text
    • http://satcomlink.com/userData/board/file/xemelebuko.pdfIn PDF document text
    • http://cavusofis.com/images_upload/files/27018785905.pdfIn PDF document text
    • https://www.highettmetal.com.au/application/third_party/ckfinder/userfiles/files/91471790685.pdfIn PDF document text
    • http://ovartec.com/wp-content/plugins/formcraft/file-upload/server/content/files/161408c9e75540---fuxosufidug.pdfIn PDF document text
    • https://amoslodge10.org/ckfinder/userfiles/files/91686793935.pdfIn PDF document text
    • https://fermuar.com/wp-content/plugins/formcraft/file-upload/server/content/files/1612f43fa63d89---pivujejikodu.pdfIn PDF document text
    • http://redskap.ru/userfiles/file/wokofugoxof.pdfIn PDF document text
    • https://gamletaarnhuset.no/wp-content/plugins/formcraft/file-upload/server/content/files/1612f5766e53a1---39377780844.pdfIn PDF document text
    • http://divorce-difficile.fr/userfiles/file/gurogasezomolapozomidajik.pdfIn PDF document text
    • https://www.wsbe17hongkong.hk/_bin/ckfinder/userfiles/files/fubok.pdfIn PDF document text
    • http://kawoka.com/userfiles/file/zupifonibobelenomazetubi.pdfIn PDF document text
    • http://inlikeflintlogistics.com/wp-content/plugins/formcraft/file-upload/server/content/files/1614b707db5ae3---lesinixojobiwumizufivuvaj.pdfIn PDF document text
    • http://koppeika.ru/userfiles/file/jusebilixata.pdfIn PDF document text
    • http://keacg.com/upload/files/nudajexumukezivaditije.pdfIn PDF document text
    • https://www.gico.ge/ckfinder/userfiles/files/2952804148.pdfIn PDF document text
    • https://totalyoumovement.com/wp-content/plugins/formcraft/file-upload/server/content/files/1614ce5aa78fbd---puxodus.pdfIn PDF document text
    • https://saftanton.dk/wp-content/plugins/formcraft/file-upload/server/content/files/161509a78aca89---vanuxinimomem.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/cv9VXjIrmdE/uplcv?utm_term=use+android+phone+as+webcam+and+microphonePDF 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_off0000b4eb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB4EB 15916 bytes
SHA-256: d9f348a9c475544b47296dc42261962d1822de667a8d9aa0056a241b6e3b21c6
font_01_sfnt_off0000dd30.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDD30 10868 bytes
SHA-256: b5d02fc6645c5fe50cbf2c148450beeec3d86361d376957a7843130da8573380
font_02_sfnt_off0000f5e3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF5E3 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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