Malicious PDF — malware analysis report

Static analysis result for SHA-256 83491ac7c23a6c30…

MALICIOUS

PDF

82.7 KB Created: 2021-09-03 20:54:22 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 180fca0b0afb0fabe0bd6d0414e4e079 SHA-1: 539adb0dae8db02a1ce8620e7a406dd2e36ceefe SHA-256: 83491ac7c23a6c3086ee9c47d6e73f7cfc9d798b92a45aec18a1b33f89481c6b
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

This PDF was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. It contains numerous external links, many pointing to compromised WordPress upload directories, suggesting a link farm or redirection mechanism. The document body is heavily obfuscated, but the presence of external URIs and the overall heuristic firings indicate an attempt to direct the user to malicious content, likely for phishing or to download further payloads.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9992

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://smidgel.ru/uplcv?utm_term=research+directions+in+computational+mechanics+pdf PDF link annotation
    • https://www.ideaklinik.com.tr/wp-content/plugins/formcraft/file-upload/server/content/files/160a060850674c---67488618930.pdfIn PDF document text
    • http://ebsenglish.net/_UploadFile/Images/file/8032478270.pdfIn PDF document text
    • http://www.akutrans.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b00b648fe6d---vanedusisarugerijiraxo.pdfIn PDF document text
    • http://barefoot.pl/userfiles/file/livefidifuwuturub.pdfIn PDF document text
    • https://charteriraq.ir/basefile/charteriraqir/files/36646872416.pdfIn PDF document text
    • https://martabaktelor.com/contents//files/kiposiriwi.pdfIn PDF document text
    • http://www.kigimex.com.vn/ckfinder/userfiles/files/xujuvivulijosusinu.pdfIn PDF document text
    • http://pajurioverslas.lt/ckfinder/userfiles/files/gawagakifaxasatazo.pdfIn PDF document text
    • http://xaydungphongphu.com/uploads/files/37463869845.pdfIn PDF document text
    • https://armenia4d.com/contents//files/31994228494.pdfIn PDF document text
    • http://shosholoza.de/file/rusidikusigapa.pdfIn PDF document text
    • http://backkwang.com/userData/board/file/9672824072.pdfIn PDF document text
    • https://vashadvokat82.ru/wp-content/plugins/super-forms/uploads/php/files/158976659fafe58d6d603bb87710c92e/buzefawedubenukerimesigo.pdfIn PDF document text
    • https://www.brunosistemi.com/wp-content/plugins/formcraft/file-upload/server/content/files/161068bf171616---mizuza.pdfIn PDF document text
    • https://gemwares.com/userfiles/file/89649919739.pdfIn PDF document text
    • https://pinotcar.com/wp-content/plugins/super-forms/uploads/php/files/bd3d557c9eb8845d56c687205b66bf85/29281264902.pdfIn PDF document text
    • http://konditsionery-odincovo.ru/upload_picture/file/lunutir.pdfIn PDF document text
    • https://www.adom.biz.pl/ckfinder/userfiles/files/gasonabanaxupikeganamizo.pdfIn PDF document text
    • https://ubitanduk.com/contents/files/62363539268.pdfIn PDF document text
    • http://imbirimbir.ru/files/56864362192.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_off0000dae1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDAE1 18848 bytes
SHA-256: ebb3a37e41b753133e0d98b8a4acdbc1341f04c22f7c2483b4b80c47920cbc99
font_01_sfnt_off00010c09.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10C09 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00012420.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12420 11028 bytes
SHA-256: a82d50fb43a9d82994fd306e978c14987efc24956917d6b5689873873c07e662