Malicious PDF — malware analysis report

Static analysis result for SHA-256 20de9b4d0d364317…

MALICIOUS

PDF

75.2 KB Created: 2021-09-21 04:25:28 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: b06f859eed751a746877de4af5f6c984 SHA-1: 85071f19be49d485f5a2b39e1461271ede7f16c6 SHA-256: 20de9b4d0d364317187ec0a8bb0b48a6c87cf3ee1572e7be9dedc2dbef7ea6e6
156 Risk Score

Malware Insights

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

The PDF file was flagged by a machine learning classifier and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate it functions as a link farm, with numerous URLs pointing to potentially compromised CMS upload directories or disposable hosting. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, suggesting it's not intended for direct user reading but rather to host links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9939

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://snabavto.com/wp-content/plugins/formcraft/file-upload/server/content/files/161345e9dd227a---rasezaturoborexiker.pdf In PDF document text
    • http://tabouligrill.com/ckfinder/userfiles/files/mibetesubuxut.pdfIn PDF document text
    • https://rosanaalvarracin.com/userfiles/file/xusatenejuvewuviguzubi.pdfIn PDF document text
    • https://autonoleggioassereto.com/file/98997727611.pdfIn PDF document text
    • http://thy-environment.com/userfiles/files/37247382302.pdfIn PDF document text
    • http://selidbe-beograd.info/files/53768055958.pdfIn PDF document text
    • https://a-pointpro.com/cms/ckfinder/userfiles/files/tutuselurofimenuvebej.pdfIn PDF document text
    • http://metapolar.hu/tmp/siwiwavupaxu.pdfIn PDF document text
    • http://vinhhangvien.com/upload/files/niviluropize.pdfIn PDF document text
    • http://www.mmalappeenranta.com/tiedostot/files/towat.pdfIn PDF document text
    • http://recamonde.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/161392b22e87b4---13823713132.pdfIn PDF document text
    • http://acpiindia.com/userfiles/file/18723364641.pdfIn PDF document text
    • https://bahia-group.com/ckfinder/userfiles/files/mizikoxediz.pdfIn PDF document text
    • https://bentzendesign.se/wp-content/plugins/formcraft/file-upload/server/content/files/1613f9d88c1828---biwukegajepozojototel.pdfIn PDF document text
    • http://chinahk-ip.com/chinahk_ip/html/files/editor/file/64095138095.pdfIn PDF document text
    • http://bjoybrands.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613389d372114---23867151825.pdfIn PDF document text
    • http://antansconstructions.com/ckfinder/userfiles/files/57868462954.pdfIn PDF document text
    • https://www.auditek.fr/wp-content/plugins/formcraft/file-upload/server/content/files/161483f7992e63---50817172549.pdfIn PDF document text
    • https://rugsinc.in/UserFiles/files/60108428715.pdfIn PDF document text
    • http://italianopizzeria-pg.com/uploads/files/wibaxudosopaluzanot.pdfIn PDF document text
    • http://bergfin.se/wp-content/plugins/formcraft/file-upload/server/content/files/16130a5af2a385---65098397151.pdfIn PDF document text
    • http://ankaraeksioglu.com/resimler/files/62988074643.pdfIn PDF document text
    • http://dokumsuzgec.com/userfiles/files/41196033207.pdfIn PDF document text
    • https://lostsoulsmemorialnj.org/wp-content/plugins/super-forms/uploads/php/files/5355c5752d7c4f92bce6cc3df6e7d37b/gewitipu.pdfIn PDF document text
    • http://haohanlegend.com/Uploadfiles/files/fetavukovojepon.pdfIn PDF document text
    • http://sm.ac.th/ckfinder/userfiles/files/muxefofutotozosa.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/GLLx1DTH0VQ/uplcv?utm_term=can+you+facetime+with+iphone+and+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_off0000c1c4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC1C4 11000 bytes
SHA-256: 064b0b9a6d766e8f437ccefa7ac90ea655a1696fa47dc6ae4128e6cdb1ab1946
font_01_sfnt_off0000db3c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDB3C 17084 bytes
SHA-256: a32e0867bbb32a53a68334d3c82d4754a182b173e7f7aec62ee80096f42c506c
font_02_sfnt_off000106e7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x106E7 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1