Malicious PDF — malware analysis report

Static analysis result for SHA-256 acf9105b3bc33365…

MALICIOUS

PDF

83.1 KB Created: 2021-09-20 15:45:53 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-23
MD5: f6178502b89c2ec50f01ccc57f20ddaf SHA-1: 9e5deaceb9afc6439e43079d7e0aff09c194ec5d SHA-256: acf9105b3bc33365c1c44421d8e190bfa5de023330869ee9281c215abd9cf444
96 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file contains numerous embedded URLs, many of which point to compromised WordPress sites or disposable hosting. The ML classifier strongly indicates maliciousness, and the structure suggests a link farm designed to redirect users. While no scripts were extracted, the extensive use of external links and the ML detection point towards a malicious intent, likely to distribute further malware or engage in phishing.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

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 https://www.generalutilities.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613773f7cfb38---26321782422.pdf In PDF document text
    • https://djennebeads.com/nbloom/fckuploads/file/39400637622.pdfIn PDF document text
    • http://owv-sad.de/userfiles/files/xuvawosidotatixer.pdfIn PDF document text
    • http://0985028898.kad.tw/kads/ckfinder/userfiles/files/88367106350.pdfIn PDF document text
    • http://aydinservis.com/ckfinder/userfiles/files/70879406613.pdfIn PDF document text
    • https://1sis.com/wp-content/plugins/formcraft/file-upload/server/content/files/161409d6bace8a---45856659767.pdfIn PDF document text
    • http://alburigiott.it/userfiles/files/rajedazulalapasalidum.pdfIn PDF document text
    • https://argumentua.com/i/file/nimajoweviruviroxab.pdfIn PDF document text
    • https://matraci.info/UserFiles/File/52780736870.pdfIn PDF document text
    • https://ahha.az/userfiles/file/bugimozufonowafas.pdfIn PDF document text
    • http://valkexclusief.reviews/app/webroot/files/userfiles/files/nipegudotofetalipez.pdfIn PDF document text
    • https://westhygiene.hu/editor_up/22280327420.pdfIn PDF document text
    • https://nasco-ye.com/uploads/file/88428699528.pdfIn PDF document text
    • http://f1-rennsimulatoren.de/userfiles/file/17991374415.pdfIn PDF document text
    • http://vanhacollection.com/images/files/rogekixevibimenon.pdfIn PDF document text
    • http://www.toptehnik.si/images/39164269615.pdfIn PDF document text
    • https://noks.cz/wp-content/plugins/formcraft/file-upload/server/content/files/16137584662cd2---tinelosubepujenidarom.pdfIn PDF document text
    • https://mylin.in/ckeditor/ckfinder/userfiles/files/32602954397.pdfIn PDF document text
    • https://davaocarrental.com/images/file/vofiworagibanomidor.pdfIn PDF document text
    • http://baltic-rt.ru/ckfinder/userfiles/files/fijufamaminan.pdfIn PDF document text
    • http://cpbnatation.fr/fckeditor/userfiles/file/67754191344.pdfIn PDF document text
    • http://dungcuthietbi.vn/Images_upload/files/tuxigutowukoz.pdfIn PDF document text
    • http://fatename.com/uploads/files/202109120604074020.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/1xuhb7AK25c/uplcv?utm_term=how+to+download+pokemon+black+2+on+androidPDF 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_off0000df44.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDF44 17720 bytes
SHA-256: 26af626051530f34c822d4f3b2359b02678dc8a8aa19dc5c47397321ae5c2204
font_01_sfnt_off00010d55.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10D55 10936 bytes
SHA-256: baace2da01a3dfcbedc5360fc33e962e4cac94da3b6a9b873440efdc45fa7965
font_02_sfnt_off00012675.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12675 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1