Malicious PDF — malware analysis report

Static analysis result for SHA-256 6b77dea5e6982061…

MALICIOUS

PDF

80.3 KB Created: 2021-09-26 01:56:33 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-24
MD5: d9789564c373e07adeee655c477cc881 SHA-1: 474449e289effc615fc2cb0a52bdb15f41ecd20b SHA-256: 6b77dea5e6982061899b6186b3d32d59f71b5f2f249ee9330f5542db453a5145
164 Risk Score

Malware Insights

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

The sample is a PDF containing embedded JavaScript, which is a common technique for exploiting PDF vulnerabilities or delivering malicious content. The PDF also contains numerous external URIs, many of which point to compromised CMS upload directories or disposable hosting, suggesting a link farm designed to redirect users to malicious sites. The ML classifier and ClamAV detection strongly indicate malicious intent, likely for phishing or malware distribution.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

Heuristics 7

  • 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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • 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://crewmak.ru/uplcv?utm_term=remove+pdf+security+mac PDF link annotation
    • https://aksusu.com/upload/files/59287695676.pdfIn PDF document text
    • https://cremeconferences.com/wp-content/plugins/super-forms/uploads/php/files/30012b196617f50bda577b77714b18ac/76351081664.pdfIn PDF document text
    • https://wickedcheesy.com/images/file/fuguvixoloba.pdfIn PDF document text
    • http://asirius.su/wp-content/plugins/super-forms/uploads/php/files/a445190f8e180f3174941a13fd0c4cc0/12909077751.pdfIn PDF document text
    • http://petrduchek.com/files/mixajigogoxu.pdfIn PDF document text
    • http://goldenstarhotel.vn/images/uploads/files/mavarozuk.pdfIn PDF document text
    • http://uyaviation.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613499a8727fe---671587875.pdfIn PDF document text
    • https://tuabogadoangel.com/wp-content/plugins/super-forms/uploads/php/files/1c7d6434dd0073ab03c71ab493691013/96075034115.pdfIn PDF document text
    • https://asi-filter.pl/files/file/lovuwivoxupofopinuk.pdfIn PDF document text
    • https://amadesafar.ir/basefile/amadesafarir/files/delijuso.pdfIn PDF document text
    • https://peperita.it/writable/public/userfiles/file/geduwugozuvigabaz.pdfIn PDF document text
    • http://efuegypt.org/userfiles/file/somad.pdfIn PDF document text
    • http://resheto.ru/users_images/fck/file/22907614990.pdfIn PDF document text
    • http://hitecds.com/userfiles/file/59453666335.pdfIn PDF document text
    • http://www.jacenter.org/js/ckfinder/userfiles/files/6491574491.pdfIn PDF document text
    • http://capesociety.ca/uploads/files/88996379001.pdfIn PDF document text
    • https://queensflower.nl/clientfiles/murorenawagabuvowewuko.pdfIn PDF document text
    • https://www.agencesramos.com/ckfinder/userfiles/files/37858103467.pdfIn PDF document text
    • http://gr-chem.com/upload/files/sebulibadas.pdfIn PDF document text
    • http://slsnn.ru/content/files/lisuvuroleleroza.pdfIn PDF document text
    • http://behtarinekhodetbash.com/files/files/67367099817.pdfIn PDF document text
    • http://www.ujepites.hu/userfiles/files/kezovapi.pdfIn PDF document text
    • https://msiutilities.net/documents/zubisedafe.pdfIn PDF document text
    • http://xn--oy2b19v1mb1yi.com/userfiles/file/19482252902.pdfIn PDF document text
    • http://pfollowers.com/ci/userfiles/files/86043491917.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_off0000cbc0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCBC0 10956 bytes
SHA-256: bf443db2f0deb59c2f5bd02adaadb84b463bc50d982c19e87d2f594ce1d5c9b4
font_01_sfnt_off0000e542.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE542 20772 bytes
SHA-256: 8ab42d809f1ce7ff71bd204cd8dab15ba154851befa5953e549b906af181b60a
font_02_sfnt_off00011b32.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11B32 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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