Malicious PDF — malware analysis report

Static analysis result for SHA-256 a79bbf7de92bf071…

MALICIOUS

PDF

34.9 KB Created: 2020-08-31 18:30:34 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: d77e69bf89ebcd4955f5ea76b7f603c4 SHA-1: fe1e76f3eb19c2408ff84210fa95216237a91d9a SHA-256: a79bbf7de92bf0715f33d3826ff19500676b2356f4ca8be08af144a7f5d8f970
152 Risk Score

Malware Insights

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

The PDF was flagged as malicious due to a critical heuristic identifying it as a redirector link to known malicious infrastructure. It also contains a link farm with numerous external PDF links, many hosted on static.usrfiles.com. The embedded document body text, though heavily obfuscated, contains the primary malicious URL. The primary intent appears to be directing users to malicious sites through a deceptive link farm.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 4

  • PDF links to known malicious redirector infrastructure critical PDF_MALICIOUS_REDIRECTOR_LINK
    PDF contains a clickable URI to redirector infrastructure used by a known malicious PDF SEO/adware delivery campaign. These documents typically rely on user interaction and redirect chains rather than a PDF parser vulnerability.
  • 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.
  • 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://ttraff.cc/wix?keyword=joyously+unrestrained+answers
    • https://static.usrfiles.com/ugd/f967ac_17fa7f48b4704f77885c2779a8bd2d1f.pdf
    • https://static.usrfiles.com/ugd/6da380_618520f9836441efa96cff3c177f9c65.pdf
    • https://static.usrfiles.com/ugd/6f7357_07f84d4108704e7e9925c59ebff9a329.pdf
    • https://static.usrfiles.com/ugd/221f3a_7b054dcfbda142098b3073bd0a901af3.pdf
    • https://static.usrfiles.com/ugd/538d67_89319156b6564100b18f19cd475fe5d5.pdf
    • https://cdn.shopify.com/s/files/1/0430/7006/2753/files/15959324564.pdf
    • https://cdn.shopify.com/s/files/1/0435/6240/1947/files/10345686735.pdf
    • https://cdn.shopify.com/s/files/1/0438/2723/2918/files/tijebomawar.pdf
    • https://cdn.shopify.com/s/files/1/0435/3146/8951/files/chaitanya_bhagwat_in_bengali.pdf
    • https://cdn.shopify.com/s/files/1/0430/5338/3833/files/putitikegiporekeg.pdf
    • https://static.usrfiles.com/ugd/b8c837_b0618a34573440f1a81cb9f089fdd66b.pdf
    • https://static.usrfiles.com/ugd/7d21c0_76169dc7a1794001bfa624601b9cd5f9.pdf
    • https://static.usrfiles.com/ugd/2c608b_9c580d2496234658a61230b7c1f4bc35.pdf
    • https://static.usrfiles.com/ugd/0511f5_6cc4553b960643449b0f58d06f9eeffc.pdf
    • https://static.usrfiles.com/ugd/6116da_08c73d28c8474c48813a95c4bb255381.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/

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off00004bd4.bin
466d2627f25a247342b4f133f55473d532d6715e876238d999c3443319528378
pdf-font-stream PDF embedded font (sfnt) at offset 0x4BD4 5000 bytes
font_01_sfnt_off00005cf8.bin
2e6af7aa32ff48dbe46e11b34889e457449badae8aabbe751fedfb4452eb4101
pdf-font-stream PDF embedded font (sfnt) at offset 0x5CF8 9944 bytes