Malicious PDF — malware analysis report

Static analysis result for SHA-256 fbca8eb45ade824b…

MALICIOUS

PDF

79.0 KB Created: 2021-03-18 14:42:48 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 65a36fe2852d729240dbf050b7d0ab6b SHA-1: 34a2b9270b964016eecfa8da7fce1ec79dbbc63b SHA-256: fbca8eb45ade824b4749ec3f968f73310a86c1c00b40975bca36fa96e7436889
186 Risk Score

Malware Insights

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

The PDF contains a large number of external links pointing to various domains, many of which appear to be disposable hosting services. This behavior is indicative of a link farm, likely used for SEO manipulation or to distribute further malicious content. The ML classifier and ClamAV detection strongly suggest malicious intent, aligning with a phishing or trojan delivery pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9991

Heuristics 6

  • 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.
  • 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 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://nipisod.ru/award?keyword=99+apache+spark+interview+questions+for+professionals+pdf
    • https://cdn-cms.f-static.net/uploads/4386848/normal_602c9886eaf01.pdf
    • https://gifukupuwabe.weebly.com/uploads/1/3/0/7/130775529/77662.pdf
    • https://cdn.sqhk.co/xovikojux/ijdigif/lurufabekuzogezu.pdf
    • https://valuluxunu.weebly.com/uploads/1/3/2/7/132710491/271197.pdf
    • https://static.s123-cdn-static.com/uploads/4465250/normal_60049356916e3.pdf
    • https://cdn.sqhk.co/rezebarowed/jgf6igH/driving_school_2017_free_play.pdf
    • https://cdn-cms.f-static.net/uploads/4380881/normal_601c60b1e8713.pdf
    • https://static.s123-cdn-static.com/uploads/4404529/normal_6009763d5d23f.pdf
    • https://static.s123-cdn-static.com/uploads/4486221/normal_5febdf43ca4ba.pdf
    • https://cdn-cms.f-static.net/uploads/4370054/normal_6022ff2cb05a6.pdf
    • https://cdn-cms.f-static.net/uploads/4479684/normal_604b4b60ddf78.pdf
    • https://jubukukovojiri.weebly.com/uploads/1/3/5/3/135306868/rufopaloru.pdf
    • https://cdn-cms.f-static.net/uploads/4486041/normal_6031f50eef005.pdf
    • https://suwitasejamuk.weebly.com/uploads/1/3/1/8/131856391/5562e5aac8900b.pdf
    • https://zogumunatol.weebly.com/uploads/1/3/1/6/131636745/xifagumelujifi.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • http://www.daltonmaag.com/
    • https://1ceef7f3-d523-4f80-a0a4-3aed54d3d17a.filesusr.com/ugd/48841a_abc8df2cf32142d5a67731c371850df0.pdf?index=true
    • https://uploads.strikinglycdn.com/files/9c482a54-4d05-4d20-856f-cdbe2b6e5f52/how_to_find_area_and_perimeter_of_irregular_figures.pdf
    • https://7404da97-7fcf-4d5f-9d5f-3f8644e6773a.filesusr.com/ugd/35f767_7b8140f8d5bc4b31a6ec21c746dc6b2a.pdf?index=true
    • https://4900ecec-7ac1-411c-be2c-b077674085c8.filesusr.com/ugd/493135_95cc82197e474875b4f4acea31e94d0d.pdf?index=true
    • https://7f3356c1-ec1f-498a-9d41-5b36c14d87b7.filesusr.com/ugd/98d33d_9f660a71b93c4c46b3d53fec487449ea.pdf?index=true
    • https://3926d074-74ab-41cc-aa9d-340192ccda4e.filesusr.com/ugd/5619e7_bc8dd9136c3442c8b8a4be2bb3cc3b29.pdf?index=true
    • https://uploads.strikinglycdn.com/files/2685781c-aadd-4468-a69d-27e07c17a3f2/learn_chinese_in_5_minutes_chart.pdf
    • https://uploads.strikinglycdn.com/files/da151f4c-98be-4baf-b417-237219e771d4/54079768927.pdf
    • 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://scripts.sil.org/OFL

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000e96c.bin
ffdb96d89e346e01b981733fddc8903a31efc9818fec1dbbe291b799d761ddbd
pdf-font-stream PDF embedded font (sfnt) at offset 0xE96C 5528 bytes
font_01_sfnt_off0000fc3a.bin
d3173bc9d3b3818a371dfb6a00cdb0daaaa940d03f62a05d4f80902d85eba483
pdf-font-stream PDF embedded font (sfnt) at offset 0xFC3A 10336 bytes
font_02_sfnt_off00011f6e.bin
b50a2106bf82917db0cd3cf88f63c5e8cc3298b343ace5cffc591b35df33d24c
pdf-font-stream PDF embedded font (sfnt) at offset 0x11F6E 4324 bytes