Malicious PDF — malware analysis report

Static analysis result for SHA-256 9bf8bec0acec523c…

MALICIOUS

PDF

76.6 KB Created: 2021-03-29 10:01:51 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-08-20
MD5: 941219c2b7b46cb7199978176bb16307 SHA-1: bc2bd953836cc23d86221e60cb4a8b7c3c73a4ee SHA-256: 9bf8bec0acec523ce9fd27097889454565d9ff41f97fb28ec956925befb27da5
186 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript

This PDF file was flagged by multiple heuristics as malicious, including a critical ClamAV detection and an ML classifier. It contains a large number of external links, many pointing to disposable hosting, suggesting a link farm or SEO spam operation. The document body, though heavily obfuscated, appears to be a lure related to 'lesson 19 cells unit test answers'. The presence of embedded URLs and the nature of the link farm indicate an attempt to redirect users to malicious or spam content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9993

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
  • Small PDF contains mass external PDF link farm critical PDF_SEO_LINK_FARM
    Small PDF contains many clickable external PDF links, mostly clustered on one host. This matches generated SEO/link-farm PDF carriers used to route users into malicious or unwanted-software delivery chains, rather than a normal document citation pattern.
  • 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://leonvi.ru/wix?keyword=lesson+19+cells+unit+test+answers PDF link annotation
    • http://wotimose.getenjoyment.net/lolobinumebobuginapux.pdfIn PDF document text
    • http://fenellalucynelle.info/alexander_the_great_military_accomplishmentsosx8e.pdfIn PDF document text
    • http://gexomafe.mypressonline.com/gifibizojepi.pdfIn PDF document text
    • http://zoguponuwuxoli.medianewsonline.com/wonitiduxufepuwujutojorig.pdfIn PDF document text
    • http://center-about.com/60149441759vgj0s.pdfIn PDF document text
    • http://dejivuxa.mygamesonline.org/backpacking_checklist_rei.pdfIn PDF document text
    • http://2220202.ru/xosami3u9v2.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://uploads.strikinglycdn.com/files/8e48391d-0710-4ebb-b010-f83da06ea6a6/how_to_find_horizontal_force.pdfIn PDF document text
    • https://s3.amazonaws.com/vavebufevodutob/espadrille_platform_ankle_strap_wedge_sandals.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/fad8c5d7-4bc2-4933-b323-ac983a3fd2c9/how_do_i_love_thee_analysis_line_by_line.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/b9b94273-6e6f-4fcb-9e7d-2b9efa7a5268/xonofubumajaluvinilaze.pdfIn PDF document text
    • http://zivonupawidam.atwebpages.com/38320388008.pdfIn PDF document text
    • https://189c2d36-84ff-4b81-9465-96c33c1d3b91.filesusr.com/ugd/35ddae_c856e8142dc84a36867d34b776a00c8e.pdf?index=trueIn PDF document text
    • https://uploads.strikinglycdn.com/files/c3419948-efd9-4d5c-81dc-f664e47b9f67/what_do_555_mean_in_the_bible.pdfIn PDF document text
    • https://s3.amazonaws.com/dazemi/jebunujiluvaxa.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/d452443d-344d-4936-a484-ba9e99322548/who_writes_the_script_for_the_big_bang_theory.pdfIn PDF document text
    • https://s3.amazonaws.com/nowokil/tugunosikix.pdfIn PDF document text
    • https://efe523a3-d756-4f55-ba91-412f3a718e00.filesusr.com/ugd/236571_1f16e7e638cd4427a664a963d8d3269f.pdf?index=trueIn PDF document text
    • https://s3.amazonaws.com/wexukufedepim/89740511890.pdfIn PDF document text
    • https://275320ff-96dd-455a-9699-a0fdc58b27a5.filesusr.com/ugd/943725_28fac9e4336d49f0a5016517e8ba98a5.pdf?index=trueIn PDF document text
    • https://uploads.strikinglycdn.com/files/9f16ef47-70d9-48cf-8940-d6fb8dcd35d6/votarumamuxedopunokajela.pdfIn PDF document text
    • https://5a4e7950-e122-4b3c-9cf7-894e7f5b1216.filesusr.com/ugd/76aeb6_7d9b85419d864007a2f3ffd433995245.pdf?index=trueIn PDF document text
    • https://s3.amazonaws.com/lolaritemukole/gogavepevalawapoxipagepu.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://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000ee36.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEE36 5036 bytes
SHA-256: fbaecb50e5c54d747cbf95d74a717ba1e3b4bf2ccf488ce7515d58c1ec0bf27f
font_01_sfnt_off0000ff7f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFF7F 10992 bytes
SHA-256: 44233cb4df155aa474fb5b1a08bc8302a3a553f6e81b8f847592a4a7d5c8fac0