Malicious PDF — malware analysis report

Static analysis result for SHA-256 821bf1ae22e83cae…

MALICIOUS

PDF

79.4 KB Created: 2021-09-22 12:44:58 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 8d3dd6313d5096b1d570fae66744a7ed SHA-1: 21d2fc349651f0916c439399dcb28ab443984552 SHA-256: 821bf1ae22e83cae0f76d5748fc1d1edb1928b27dfe6ef40c542110bd470b3c6
156 Risk Score

Malware Insights

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

The PDF file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. Heuristics reveal it functions as a link farm, directing users to multiple external URLs, some hosted on compromised CMS platforms. The presence of numerous PDF links on disposable hosting and the use of UTM parameters suggest a phishing or malware distribution campaign.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9981

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://philabc.ru/uplcv?utm_term=android+play+store+download+pending PDF link annotation
    • http://detskaoptika.cz/ckfinder/userfiles/files/gafek.pdfIn PDF document text
    • http://metabolit.ru/files/file/buzazerirabawifo.pdfIn PDF document text
    • http://premiumresourcing.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613b67bfdd28c---79741548878.pdfIn PDF document text
    • https://tahubunting1.com/contents/files/nutaxi.pdfIn PDF document text
    • https://lacgl.org/upload/editor/file/lawaginadipereno.pdfIn PDF document text
    • https://luxartparquet.com/wp-content/plugins/super-forms/uploads/php/files/66a2e84d650937191aa12d3d4fa9eb36/fosuxanaxeg.pdfIn PDF document text
    • https://chief-moving.com/editor_upload/file/mogutetefubifafotezejaxas.pdfIn PDF document text
    • http://goldway.jp/upload/board/file/risewunelip.pdfIn PDF document text
    • https://xn--78-6kce7dfhb9dwb.xn--p1ai/wp-content/plugins/super-forms/uploads/php/files/865ab43ec0f013c741ca39dec43b583e/rodutiwaduvurumeserafosa.pdfIn PDF document text
    • http://distant-property.ru/fck_editor_files/files/foxefum.pdfIn PDF document text
    • http://doudou.tw/userfiles/files/98204545767.pdfIn PDF document text
    • https://alusol-kw.com/ckfinder/userfiles/files/purufusim.pdfIn PDF document text
    • http://dancephoto.ru/userfiles/files/32755656839.pdfIn PDF document text
    • http://jshanwoo.com/ckfinder/userfiles/files/50438820940.pdfIn PDF document text
    • https://vienhung.com/webroot/img/files/53914699684.pdfIn PDF document text
    • http://cn-biyoute.com/d/files/43093544236.pdfIn PDF document text
    • https://gservicepz.com/wp-content/plugins/super-forms/uploads/php/files/fd5613b7014e795b4b906b324104fca3/11924670183.pdfIn PDF document text
    • http://transportdiverse.com/uploads/files/sonodakimukibulifa.pdfIn PDF document text
    • https://totalyoumovement.com/wp-content/plugins/formcraft/file-upload/server/content/files/16149a38bd3c49---mevifebuf.pdfIn PDF document text
    • http://k12kos.com/ckfinder/userfiles/files/wibirigadakokegobawik.pdfIn PDF document text
    • http://rosabaum.de/web/editor/files/vijamim.pdfIn PDF document text
    • https://rm-parketi.si/uploads/59359199641.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_off0000d65f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD65F 15848 bytes
SHA-256: 28a9193076f2eb6ed296ddbe3fdcda590fd3eb59f4fd6fb4cfdfe7aae0e27180
font_01_sfnt_off0000ff2f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFF2F 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00011746.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11746 10748 bytes
SHA-256: d89bf8095c48ee291b86ae3d9c756e9e39a5b06030c2a1bad3a51acf79819208