Malicious PDF — malware analysis report

Static analysis result for SHA-256 81ba2f8b898b3691…

MALICIOUS

PDF

80.1 KB Created: 2021-09-10 03:18:48 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-05
MD5: 3058e9380c8b934ea4400a4447cd030d SHA-1: 8be63dc37db3408eeb94707eaef4fb1f6e1ccb81 SHA-256: 81ba2f8b898b3691a5eaa1c14b6cd7156dff502dddf792bffee8fb87ee13c798
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. Heuristics identified it as a PDF link farm, with numerous URLs pointing to compromised CMS uploads and disposable hosting, suggesting a phishing or malware distribution scheme. The presence of embedded URLs and the nature of the link farm indicate an attempt to redirect users to malicious sites, likely for credential harvesting or further payload delivery.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9993

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://drafthe.ru/uplcv?utm_term=picsay+app+download PDF link annotation
    • http://majstrissmt.eu/www-data/file/gigot.pdfIn PDF document text
    • http://jjinline.org/file_upload/file/75529981821.pdfIn PDF document text
    • https://thieumaunao.vn/workspace/develop/uploads/ck_upload/files/46101351581.pdfIn PDF document text
    • http://heureka-cz.eu/files/jomaximun.pdfIn PDF document text
    • http://trenermichal.pl/wp-content/plugins/formcraft/file-upload/server/content/files/1613a86e4172ab---38377908825.pdfIn PDF document text
    • https://israelonthehouse.com/wp-content/plugins/formcraft/file-upload/server/content/files/16139a30662572---42195755107.pdfIn PDF document text
    • http://olynskiconstruction.com/pics/file/bijiloxalexojurobo.pdfIn PDF document text
    • https://saigonservices.vn/images/uploads/files/zemedagenavibivupe.pdfIn PDF document text
    • http://nissanotogovap.com/uploads/images/files/liwumawifigivugojufokuk.pdfIn PDF document text
    • http://varadimasszazs.hu/uploads/files/72500082791.pdfIn PDF document text
    • http://twtqedu.com/userData/ebizro_board/file/79298435874.pdfIn PDF document text
    • https://bunyaminerdemir.com/resimler/files/66127960795.pdfIn PDF document text
    • https://tecsal.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1612fd8c4debcb---552747210.pdfIn PDF document text
    • https://hung168.tw/UserFiles/files/12822150066.pdfIn PDF document text
    • http://phanphoiongnhuahoasen.vn/upload/files/lubali.pdfIn PDF document text
    • https://www.onestopnaturalstore.ca/wp-content/plugins/super-forms/uploads/php/files/kqof82p7n1uhje204nutkv74um/38649501104.pdfIn PDF document text
    • http://holzbau-napetschnig.at/26709123716.pdfIn PDF document text
    • https://yucekalipmakina.com/tsrm1/img/userfiles/file/foribinavatipilamedigav.pdfIn PDF document text
    • http://kindervakantieweekdeurne.nl/wp-content/plugins/formcraft/file-upload/server/content/files/1612f2a27cae41---mezajevuromipono.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_off0000d699.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD699 17748 bytes
SHA-256: c53265d94d93f625617849ad93eea97106a303d844f642f5cd18dc5d89a2cd1c
font_01_sfnt_off000103dd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x103DD 10380 bytes
SHA-256: 447f2ba600d025e450f4f59d94ee80cae688b58a2cad79b8e7c8c419b4186f0f
font_02_sfnt_off00011b7c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11B7C 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1