Malicious PDF — malware analysis report

Static analysis result for SHA-256 831bd6c8b4a7f414…

MALICIOUS

PDF

79.8 KB Created: 2021-09-22 11:05:11 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 9eb7b79d10145f90698cb5fe83ee221e SHA-1: fadace66f00c87e06415a3e1366b226798eae65f SHA-256: 831bd6c8b4a7f41481e24474b4fe01b0f734b4d683cfeeeaba0e357e44786469
156 Risk Score

Malware Insights

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

The PDF file was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate it functions as a link farm, directing users to multiple external websites, some hosted on compromised CMS platforms. The presence of numerous embedded URLs, many pointing to unknown or potentially malicious domains, supports the conclusion that this document is designed to redirect users to harmful content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9953

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://okmarin.ru/userfiles/file/nodijazuxifoxaridum.pdf
    • http://canshu.dlzj.net/upload/files/20210908232107388974.pdf
    • http://kelakewangshangduchang.a9188.com/upload_files/art_files/files/20210921_005150.pdf
    • https://terminarz.online/kosmetyczka/krakow/files/80476273763.pdf
    • https://biocoils.com/img/file/73988309658.pdf
    • https://deltarents.com/upload/ckfinder/files/ropixono.pdf
    • http://miass.realxenon.ru/uploads/files/timetobajakadunuku.pdf
    • http://decentlogistics.pk/survey/userfiles/files/biraforogixonalobafenebog.pdf
    • https://apexsafetyproducts.com/ckfinder/userfiles/files/87191516956.pdf
    • http://erbamedica.org/userfiles/files/xebozet.pdf
    • http://scard.vn/app/webroot/uploads/files/39209966728.pdf
    • http://spc1991.com/ckfinder/userfiles/files/1784005603.pdf
    • http://cl-metalparts.com/d/files/zonazow.pdf
    • http://xn--80ackbssfuieecff0e8c.xn--p1ai/wp-content/plugins/super-forms/uploads/php/files/etbm5li53co0982qoqp323jhn1/7923006338.pdf
    • http://shqinze.net/admin/upimg/file///52342372273.pdf
    • http://tetrafluoro.com/upload/files/lejaj.pdf
    • http://baove24h.info/upload/files/gexelevurakujurewoda.pdf
    • http://versobrokers.eu/userfiles/files/31237749629.pdf
    • http://www.srijonihealinghome.com/fckimages/file/15080737293.pdf
    • https://jamiatulbanat.in/wp-content/plugins/formcraft/file-upload/server/content/files/1613a48aceded0---22985976969.pdf
    • https://aademvegabaja.org/images/image/47560583433.pdf
    • http://www.tenniscanberra.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/1613037c7ad3eb---67557301248.pdf
    • http://kayapalinakliyat.net/file/48326059444.pdf
    • http://toanlinh.vn/upload/files/zotulepasate.pdf
    • https://feedproxy.google.com/~r/Uplcv/~3/YTWXjIUwRh0/uplcv?utm_term=iphone+camera+scan+barcode
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000d436.bin
c30da5a4d3799c96e8952e6b69faa06643dcace10d503f2381b8cfae68844e2e
pdf-font-stream PDF embedded font (sfnt) at offset 0xD436 17420 bytes
font_01_sfnt_off000101db.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x101DB 16792 bytes
font_02_sfnt_off000119f2.bin
f0802153c1b54b9b2bfd38f78dc303ce4e781cd5ce0661023e8f9b05932d53e3
pdf-font-stream PDF embedded font (sfnt) at offset 0x119F2 10632 bytes