Malicious PDF — malware analysis report

Static analysis result for SHA-256 bdcc26b9835a1366…

MALICIOUS

PDF

70.6 KB Created: 2021-06-08 22:39:31 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-09-27
MD5: bfc7c597e63af4266d23cb0e783a062f SHA-1: c051f9a2f0e150e82997737597e9dcec78c79048 SHA-256: bdcc26b9835a1366dbe6e05d57cf8d69a5b9ef3b46404bb329c6119a5dae1085
186 Risk Score

Malware Insights

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

This PDF file was identified as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. It contains a large number of external links, many pointing to disposable hosting, suggesting it functions as a link farm or phishing lure. The document body, though heavily obfuscated, contains metadata related to 'Spanish present tense exercises' and the wkhtmltopdf tool, likely serving as a deceptive pretext to encourage users to click the embedded links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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
  • 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://coretry.ru/pbw?utm_term=spanish+present+tense+exercises PDF link annotation
    • https://cdn-cms.f-static.net/uploads/4393641/normal_5fd6520c15f2e.pdfIn PDF document text
    • https://kovipokuvukos.weebly.com/uploads/1/3/4/4/134497495/212806573f2.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4490920/normal_5fd798f6adb61.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4419629/normal_601aa85c35cfb.pdfIn PDF document text
    • https://fineruliji.weebly.com/uploads/1/3/4/3/134313455/b37ea117.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4485587/normal_6061fa72d4444.pdfIn PDF document text
    • https://dumerozum.weebly.com/uploads/1/3/4/6/134611270/revifimipaxibi.pdfIn PDF document text
    • https://vowomupow.weebly.com/uploads/1/3/4/8/134846305/lurorixiza-pegab-fugoxikuj-pedijijubuzu.pdfIn PDF document text
    • https://galebekamabe.weebly.com/uploads/1/3/4/3/134305591/9591569.pdfIn PDF document text
    • https://guzesunidami.weebly.com/uploads/1/3/0/8/130873942/7765793.pdfIn PDF document text
    • https://daliroxemonove.weebly.com/uploads/1/3/0/7/130775241/d33f40b25848ee0.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4377909/normal_606e47289a745.pdfIn PDF document text
    • https://kepinofex.weebly.com/uploads/1/3/4/0/134017679/bejob.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://gaguwufajij.pbworks.com/f/92530867654.pdfIn PDF document text
    • http://gogoporiwo.pbworks.com/f/hack_mlive_unlock_room.pdfIn PDF document text
    • http://bofamawetodo.pbworks.com/w/file/fetch/144633261/43000437377.pdfIn PDF document text
    • http://mukibilevejo.pbworks.com/f/software_raid_mac_os_x_el_capitan_dmg_bootable_usb.pdfIn PDF document text
    • http://farejutotej.pbworks.com/f/zolaluxamapinidof.pdfIn PDF document text
    • http://jolunatimavu.pbworks.com/w/file/fetch/144505698/a_court_of_mist_and_fury_series_in_order.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_off0000d361.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD361 5160 bytes
SHA-256: b3adc37c42ddc1ac1841cb9e2e99e3d9a79e4cf1d8d8bd21e6c6a2e65fa1de4f
font_01_sfnt_off0000e4e9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE4E9 11852 bytes
SHA-256: 4c11f75c627b079c005f6f5f7693f20b617adcd72089d1bef6bd0fc7e926ecb8